Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Sherwood on November 18, 2020, 05:33:37 PM
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I've blown my controller. When I opened the controller up I found a capacitor rattling around ... unused, not soldered in, must have been solder shop quitting time and the Mrs had cooked a good meal. I have a 3 axis router with Lin Engineering 5718L 03D steppers and US Digital E2 optical kit encoders, limit switches and run it via a parallel port on Mach3. All these are in good condition. I'm looking for a suitable DIY controller kit with the entire kit and caboodle to run the mill efficiently. Do any of you know of a suitable kit and supplier? I am retired, do not have very deep pockets but still would like something of quality. A beer pocket and champagne taste so to speak. Look forward to your suggestions.
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you write your Controller is blown, and also that everything is connected/running via a parallel port on Mach3.
so witch cntroller is blown?
some Pictures would be helpfull to get to the entire Problem.
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I hope this jpg arrives, TPS. My computer, running Windows XP, is dedicated to Mach3 and is attached to the CNC via circuitry as per attached jpg. Each of the x,y and z axis stepper motors has 5 wires, blue, green, red, black, white and brown; each motor plugged via a 5 wire plug into a 'Motor' connector into the circuit board. Each US digital E2 optical kit encoder has 5 wires, red, green, bare, white and black, plugged into a 5 wire 'Encoder' connector. The limit switches are plugged in via a connector with red and blue wires. The circuit board is connected to a power supply via two white plugs, one with two green wires and the other with a black and green wire. The circuit board is connected to the computer via a 25 pin Parallel port cable to the computer's printer port.
The TIP120 transistor connecting the X axis motor's black wire to the PIC16F84A-201/P microchip has failed twice, while the transistor connecting the X axis motor's red wire to the microchip was not installed but loose in the circuit box. A friend soldered it onto the board. I did not know that one transistor was not installed till after the first failure. The burnt out transistor was replaced with a new one and the other was soldered in, and the machine ran well for a day when the new black wire transistor burnt again. All motors run well on the Y and Z channels, but the X channel is ratz. I think new circuitry would be required but I do not really know what to do next. Your advice would be greatly appreciated.
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My attempts to send attachments result in errors, TPS, is there another way to do it?
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witch error is showing up, sometimes it helps to rename the file to be unique.
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Try again
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My apologies, the transistors are attached to the DM7400N semi conductors, not the PIC microchips.
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if the power Transistor for the x-Motor has blown twice i would start with the Motor itselv.
maybe your friend can measure the resistance of the Motor.
if you have two Motors of the same type you can compare.
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Will do. I've also requested the tech specs from Lin Engineering as I do not know what each of the 5 wires are for. Let you know when it's done. Thanks
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The circuitry.com file shows a circuit for unipolar stepper motors. 5 wire connection is a common configuration for unipolar motor. Unipolar motors are slower and less powerful than bipolar.
https://www.oyostepper.com/article-1076-Some-differences-between-bipolar-and-unipolar-stepper-motor.html
If you need to replace more TIP120s use TIP122. It has a voltage rating of 100V instead of 60V for the TIP120. This will help if your failures are caused by voltage spikes.
TPS's suggestion of swapping motors will help troubleshoot the problem.
One of the motor wires will read the same resistance to all the other wires. Color codes vary but that common winding center tap is probably the white and brown wire.
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if i follow the wirring diagram it is a 6 wire Motor, witch is also quite normal for a unipolar Motor.
anyhow there is no current protection in this circuit diagram, so if the Motor resistance (sorry dont know the right english word) is somehow shortend it will burn the TIP120.
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Yes TPS, I'll have to learn to count, it is a 6 wire motor. My friend will be here sunday or monday to compare X stepper versus Y and Z stepper resistances. We live quite remotely here so have to travel quite some distance to meet. I've attached a jpg of the power supply to the circuit, that might show if it has surge protection. We certainly have power surges in this area. There is a trip button on that box that seems to pop out fairly often, so that could be it. I will also install a Power Shield between the CNC and 240V power point to prevent surging.
I have connected all 3 motors to the Y and Z channels and they behave very well but all three motors behave badly on the X channel.
By the way, the circuit board has an A axis channel; could I use it to drive the X axis motor?
I will install TIP122 transistors from now on, thanks for the colour coding info as well MN300.
Will be back once the motor resistances have been tested.
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When I read your earlier post about having 5 motor wires I assumed the last wire was white and brown. If there are really 6 wires then 'color code 1' under '6 lead wires' would seem to apply.
https://lin-web.s3.amazonaws.com/downloads/products/hybrid-stepper-motors/Lin%20Engineering%20Catalog%202020.pdf
You asked if the A axis channel could be used with the X axis motor. They seem to be identical so if you can setup the software to address it that should work. Remember to transfer the encoder wiring. Note that the diagram shows that unused encoder inputs should be grounded.
As a last resort you could try swapping encoders between axes. This may entail some risk of damage or incorrect installation so I hesitate to suggest it.
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This motor was made by Lin Engineering for MaxNC who went out of business some 10 years ago. I've questioned the brown wire with Dave from Lin Eng; as far as he knows it should be the colour code 1 for unipolar motors, but that has a yellow and not a brown wire. The question now is whether or not the colour configuration has been changed by MaxNC, and should that matter.
I'll try the A axis channel for the X axis motor once they have been tested for resistances. Earthing the appropriate X axis Encoder pins is as easy as changing an appropriately wired plug supplied by MaxNC from the A Encoder connection to that of the X Encoder. So I'll plug the X motor into the A motor channel and the X Encoder into the A Encoder Channel .... that would work, wouldn't it. Would I then swap the X axis info and the A axis info in Mach3 Config motor Outputs and Input Signals, and would I need to change other setting in Mach3?
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You can swap X and A axis
now you should have in Config -> Ports&Pins -Motor Outputs
X-Axis should use PIN 6 and 7
A-Axis should use PIN 2 and 3 if it is enabled
use PIN 2 and 3 for X and disable A
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Thanks TPS, yes, those are the values in 'Motor Outputs' and I will make the changes.
Please confirm though; no changes at all to 'Config - Ports and Pins - Input Signals' and 'Config - Ports and Pins - Output Signals'?
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Also, which of the 6 wires would be the centre tap
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If 'Color code 1' in the table mentioned earlier is correct white and yellow are the center taps of the two windings. They should both be connected to a terminal on the board motor connector.
In a 5 wire motor they would have been connected internally to one wire leading out of the motor.
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Thanks MN300, but the colour code is not exact as there is no yellow but a brown wire. Looking at TPS' highlighted pic of the X Motor contact (Nov 19), 1=Blue, 2=Green, 3=Red, 4=Black, 5=White and 6=Brown=Earth.
Considering the above, which would be the centre taps or, how to determine them.
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The terminal with the number 5 in TPS's drawing is the center tap.
As I mentioned earlier you can determine the center tap with an ohmmeter, it's the one wire that measures the same resistance to the others.
The brown earthing wire is not counted when determining if it's a 5 wire and 6 wire motor.
I can't find a Lin Engineering diagram for a 5 wire motor. Is there a chance two wires are connected together somewhere between the motor and the board connector?
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Thanks, so that means that the resistance between wires 5 and 1, 5/2, 5/3 and 5/4 would be the same, while the resistances between other combinations (i.e. 1/2, 2/4 etc) would differ.
I did read somewhere in Lin Engineering that the hybrid 6 wire 5718L series motors (my motors) can be connected as either a unipolar 6 wire or bipolar 5 wire but cannot find the references anymore. Will go looking.
I'll check the wire harness to see if wire config has been changed between the motors and the board.
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I am waiting to hear what the winding resistance is. Also a few voltage checks would be of interest. With the drives enabled would you please measure the voltage from ground to pins 1,2,3 and 4?. If you have a basic stepper drive two pins will be the nominal supply voltage, about 17.5V and the other two will measure about a volt.
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Hi MN300
My friend with the multimeter, but most importantly, 'know how', will be here most likely Monday, possibly tomorrow. We live remotely here so have to travel some distance to meet. I'll have all the data then. Will definitely also look at the voltages as suggested by you. Also the harness configuration.
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Hope this gets there
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Yup, it did.
I checked the harness. The brown wire is a separate circuit board to motor casing/CNC frame earth and does not come out of the motor. The motor is a standard Lin Engineering colour code 1 with a yellow wire (pls view last attachment). The white and yellow wires are combined and insert into TPS' 5th pin into the board.
I have not as yet found the reference to wiring the 6 wire 5718L motor to 5 wires; still looking.
So does that mean that pin 5 yellow and white are the centre taps?
Also, does the motor now function as a bipolar?
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Found the reference to wiring 6 as a 5 wire
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just for swapping the axis that is all.
to have a "deeper" look into your configuration pls post your Profile XML file.
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My attempts at attachments keep on showing errors, I'll try again
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*********
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Worked this time. I have to thank you (TPS) and MN300 for your time and effort, it's invaluable. I'm on a steep learning curve and couldn't do it without you.
You have my kindest regards
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Your motor control circuit is a unipolar constant voltage type. Most CNC applications use bipolar constant current.
https://www.motioncontroltips.com/what-is-constant-voltage-drive-for-stepper-motor-and-when-is-it-used/
While your motors may be able to be run in the constant current mode the motor control circuit is only unipolar. Unipolar motors are usually used in applications like printers where low cost is important and high speed is not needed. Often those motors are only energized while stepping and depend on the magnetic field of the motor to hold position when stopped. That's why I asked about the voltage readings.
You would get an improved performance from the motors with a better drive. However that's a major cost. There are many posts by joeaverage with information about the available choices.
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anyway, had a look to your Profile file. nothing Special in there, so swapping X and A should be running like suggested.
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today i had a look to your Motor setting's, i think a couple of the setting's are not "real", but this is a Point later on the road.
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Yes, TPS, that would be good to look at because when all was 'running well' before it ran at a snail's pace.
The X, Y and Z resistances 5/1, 5/2, 5/3 and 5/4 range between 1.4 and 1.6 ohm.
The voltages between pins 6 (earth) and 1, 6/2, 6/3, 6/4 and 6/5, with the power connected and switched on but NOT with the computer attached, are all between 17.4 and 17.6 V. There are no connections between pin 6 and other pins that are below 17.4 V.
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Your readings suggest the motors are pulsed rather than powered continuously.
If you were to apply 17 volts to a 1.6 ohm winding continuously it would draw over 10 amps. You may have seen the note on the circuitry drawing showing the max supply input current is 4 amps. 3 motors times 10 amps would be 30 amps, double that if half stepping mode is used.
Also if continuous power is applied to a winding it would receive 170 watts (10 amps times 17 volts). You have not reported any great clouds of smoke, making that possibility very unlikely.
https://www.electronicshub.org/wp-content/uploads/2017/03/full-step-one-and-two-phase-ON.jpg
Full stepping can be done with momentary pulses. Half stepping requires continuous power to hold in the half step positions.
10 amps also exceeds the the current rating of the TIP120. When voltage is applied to an inductor it takes time for the current to build up. The correct length pulse could allow enough current to move the stepper but not exceed the maximum.
The TIP120's are likely failing for one of two reasons. One is if the maximum pulse current is too high. There's little we could change to help that beyond reducing the supply voltage which would reduce power and limit speed.
Another problem is heat build up in the transistors. The more pulses per second, the more heat needs to be removed.
MACH 3 may be moving the motor faster than the original controller did causing more heat. Did the failures happened after long high speed moves?
Reducing the maximum speed may be a way to work around the problem. Better airflow or a fan would keep the transistors cooler.
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Much to learn.
Originally, the CNC was built to be run on a Mach version called MaxPath42 but I installed Mach3 instead. The machine has never been used to do a job as I was learning to understand the processes. I got as far as setting up the configs, motor tuning, jogging, setting Soft Limits, loading up G Code and "Cycle Start' dry runs in Mach3. It was then that the TIP120 burnt out ......smoke galore. The X Channel had only 3 out of 4 TIP120 installed as the 4th one was loose in the circuitry box. We installed both the loose and a replacement TIP120, tried again and after some 4 hours the same thing happened ..... again plenty of burning plastic, with a very hot X axis motor. The Y and Z channels and motors were fine.
The machine jogged at what to me was a good speed, but when in 'Cycle Start' mode, at an absolute snail's pace.
I have emailed Dave from Lin Engineering to see if the readings are within specs and for more info on motor characteristics with this wiring configuration; I expect an answer hopefully by tomorrow. It'll be interesting to see if the motors are functioning within specs.
So what I understand you are telling me is that with these readings, the motor would draw a current that can not be met by the circuitry without causing some damage to the TIP120 unless the pulse length is controlled. Would that be a circuitry function or an original setting in the MaxPath42 config, which I may not have picked up in the Mach3 settings? If circuitry, no wonder MaxNC went bust.
Heat build up could be a problem with temps here in the good land of Oz reaching the high 30s Celsius, so opening the box an applying more airflow can be arranged.
Limiting or reducing speed further than it already is in 'Cycle Start' mode would maintain a snail's pace or bring it to a virtual stand still. This issue may be related though to the issue TPS has just raised yesterday re the Motor settings not being 'real'. Could we go into that further, TPS?
I would prefer to wait with the trial run till I've received all info, just in case I blow the A Channel now used as the new X Channel up.
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for a correct Motor Tuning we Need to know how the Motor are connected to the machine.
direct via ballscrew ? via teethbelt ?
the we Need to know what one Rotation of the Motor is the real distance of traffel?
than we can further on to get the correct Settings for Motor Tuning.
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The lead screws are directly attached and in direct line with the motor shafts so one turn of the motor (200 steps) is one turn of the lead screw. The X and Y lead screw pitches are 2.55 mm each and the Z pitch is 1.61 mm. There is some error in this reading as my calipers are quite cheap and loose. The error may be 0.05 to 0.1 mm. I will reduce the error tomorrow as lighting is not great in the shed at night.
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2.55 mm/rev is suspiciously close to 2.54 mm or 0.100 inch. At 200 steps/rev travel would be 0.0005 inches per step.
The Z axis would be 0.000317 inches per step, not as good a match to imperial units.
I tried to find specifications for the maximum feed speeds but had no luck.
A wild guess, back of the envelope calculation says 1000 mm/min is the maximum X or Y speed. That's far less than your MACH settings.
I think the pulse width is programmed in the PIC, not accessible to the user. I estimate it to be about 0.250 millisecond.
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Dave from Lin Engin confirms what we know so far but adds that 'If the motor windings get overheated the insulation on the windings can begin to break down over time leading to shorting or performance issues'. Could be possible that has happened since the TIP120 burnt out; but the motor ran cool before that. What is 'shortening'?
I have averaged the Z lead screw pitch over a few distances and come 1.606 mm, so 1.6 mm is not too far off. This lead screw has the smallest diameter.
MN300, 1000 mm/min travel, should that be 100 mm/min? TPS looked at this issue on a different post and we tested the metric distance travelled against the line G1X100 F100 starting X at 0; 100 mm or 10 cm took exactly one minute. I must say that I do not really understand the issue with the Mach settings, would either of you please explain them to me.
If the required pulse is determined by the PIC120, would replacing it with a PIC122 change the pulse duration and strength? How would that affect the motor?
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Perhaps I missed something. Does the X motor now run hotter than it used to before the TIP120 failure?
"Shorting" in this case would mean the insulation between the copper wires inside the motor has broken down allowing adjacent wires to touch so the current can take a shorter path. The motor current would increase causing heating of the motor and transistor.
It's hard to measure low value resistance accurately with a multimeter. I assumed the range of 1.4 to 1.6 ohms was from measuring error. If not that could be an indication of a shorted winding.
I am guessing the highest reasonable speed for X and Y is 1000 mm/min. In your test G1X100 F100 you set the speed at 100 mm/min (F100).
It would be very useful to know the intended maximum feed speed so you can remain within the safety limit. Perhaps Dave from Lin Engineering could supply that information.
When I said your settings are higher than 1000 I was referring to to the information in the images of the motor settings.
Before we knew about the low resistance of the motors I was more concerned about voltage spikes. Except for the voltage rating the specs of the TIP120 and TIP122 are the same.
I think you may be confusing the TIP120 transistors with the microcontrollers PICnnnnn. (I can't read the exact number)
The PICs each have a step and direction input and drive the 4 TIP120s for their axis. There are also 3 signal lines common to the 4 PICs. One is probably an enable, other is possibly a fault output.
If the system is running happily with the transistors replaced maybe running below the maximum feed speed will be enough. The Z axis max will be proportionally lower as it has a different leadscrew pitch.
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I only noticed a hot X axis motor the last time the TIP blew up. The Y and Z motors were cool. I did not feel the X motor temp the first time the TIP blew up.
All three motors measure a resistance of 1.4 ohm across 5/1, 5/2, 5/3 and 5/4. So if the X motor is shorted, then the Y and Z would be as well ..... I hope not.
I have sent another email to Dave, but he seems very reluctant to give specifics on this motor as it is a proprietary product. I have asked him for the name of the manufacturer for whom they manufacture this product, hope he'll give it to me.
Yes, I was confusing the TIP120 with the PIC16F84A-201/P. Good to know I could still swap the TIP120 with a 122.
The motor settings have always been a mystery to me. How is it possible for instance for 200 steps (1 full revolution, 360 degrees) to move the X axis 2.54 mm (screw pitch) and yet the 'X Axis Motor Movement Profile' states that the 'steps per mm' is 39.2343239, which is approx 5.1 mm per full revolution. I've always just accepted it as a Mach3 internal mystery. Now if, as TPS says, the settings are not 'real' than the velocity, acceleration and other settings would also be unreal. What are the generally expected values in motor tuning; how do I arrive at correct values?
Unless you have real misgivings and would like me to check the resistances or anything else with a different instrument, I will assume that the motors are still functioning normally. So then the only issue to be resolved before I 'fire up' is the speed; maybe in the Motor Tuning setting ...... I need help there. The 'steps per (mm)' in the 'X Axis Motor Movement Profile' window are arrived at automatically by 'Calibrating the Axis' under the 'Settings' tab in Mach3. I follow the steps after activating the 'Steps per Unit' button, and the calculator inserts the 39.---- value. I do this a few times to reduce the error as far as I can and then tweak the acceleration and velocity till the gantry movement is smooth. Is this the correct procedure; could there be an error elsewhere in the settings??
And then there is the 'working' speed' ... it seems so very slow. Is that because it is a unipolar slow machine?
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200 steps divided by 2.55 mm = 78.4313725 steps/mm, twice the 39.2343239 value you're using. The lower value would make sense if you have a two start leadscrew. (double thread) If that's the case my estimate of max speed would double.
Can you look at the G code and see what feed speeds have you been running?
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The 78.---- value makes sense. I've only been playing with roadrunner.tap, the file that comes with Mach3. I am so far not up to speed with what the codes mean. There is an F60.000000; would that be it?
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Aaaaah, MN300, just got educated on thread starts .... thanks for that. Took the other 2 motors off and lead screws out and had a look at the ends of all the lead screws. Both the X and Y lead screws have two thread starts and the Z lead screw has 4 thread starts.
So the steps per mm for the X and Y axes are 200/2.54=78.74 divided by 2 (thread starts) = 39.37 steps per mm.
For the Z it is 200/1.6=125 divided by 4 (thread starts) = 31.25 steps per mm
Fairly close to the present profile figures.
So X and Y speeds double and Z speed quadruples.
How should I configure the axes motor movement profiles; just enter the steps per minute as calculated?
And what velocities and accelerations would be best; tune them so that the motors and gantries run smoothly?
Are there other config adjustments to be made?
Now to Feed Rate; once again a steep learning curve. Please correct me if I'm wrong.
So the G code for Feed Rate is F, say F20, F60, F1500 etc, and the F value is always per minute: i.e. in my case F60 is 60 mm per minute or F125 is 125 mm per minute etc.
Is that correct?
So I can set the Feed Rate (F value) to reflect the speed my motors can handle and that is why you are questioning which max speed they can handle .... is that correct?
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Normally a hobbyist will tune a stepper by finding the acceleration rate or speed that make the stepper stall or lose steps and setting the limits considerably lower. Those values depend on the mechanics of your mill and later the tool loading. It should be safe to experiment with acceleration rate but too high a speed may pop more transistors. That's why knowing the original feed specs would be good.
Once you know the limits, the values you use to actually do useful work are determined mainly the material being machined and the tool. References like the Machinery's Handbook or the Engineers Black book will help you to find appropriate spindle speed and feed rates. The G code generator program that converts your drawing to G code uses such information.
Find online tutorials that you are comfortable with and watch YouTube channels related to CNC. Here is one example.
https://www.youtube.com/user/saunixcomp
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I'll reset the stepper values and set the max speed at 1000 as you suggested and re-assemble the machine for a trial run. I'll follow up all your suggestions. Dave was not able to give me the info required so I'm flying blind on original feed specs.
Will let you and TPS know how things went.
Much thanks and appreciation.
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1000 was based on a conservative guess at the maximum stepper speed with a single start lead screw. That would be 2000 with the 2 start leadscrew.
The speeds you actually use for machining will probably be lower but being able to jog at a higher speed would be convenient.
The penalty for going too fast seems to be only the cost of a TIP122 so after you have had a period of problem free running you could raise the speed.
Check the motor temperatures so you have an idea of what's normal and can tell if it increases to much under harder use. The 5718 series motor has a Maximum Case Temperature of 176 °F. Around 130 °F it's hard to keep a finger on an object. Of course an IR thermometer is a better way to check. They're not very expensive these days.
A quick blow fuse in the center tap lead should protect the motor from overheating in case of a shorted transistor. Start at 1 amp and increase it if they blow during normal operation.
Take a picture of the end of the circuit board with the TIP120's. Maybe there is a way to add a better heat sink.
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will do all that.
Following the same rationale, could I set the Z axis speed at 4000?
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Let's try
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Test run not successful for X Axis
The A axis and X axis pin numbers were swapped in Config - Ports and Pins - Motor Outputs. The X axis now has Step Pin 2 and Dir Pin 3
I entered the updated Motor Tuning values with X and Y veloc as 2000 and Z veloc as 4000.
X axis does not function, Y and Z axes function well. Nil smoke, nil motor heating
Is there another setting in (maybe) Ports and Pins that has to be altered?
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I've swapped the X motor to the Y channel and Y motor to the new X (A) channel; the X axis motor runs well on the Y channel but the Y motor does not run on the new X (A) channel.
So the A channel is not being picked up as the new X channel by the computer / Mach3.
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You calculated Z and Y to be 39.37steps /mm and Z to be 31.25. That puts Z traveling about 25% faster -2500mm/min. I had to guess at several factors so my number could be well off, I chose the conservative answer.
When troubleshooting a problem a good method is to consider what has changed. In this case it's changing to MACH 3 software. Inadvertently selecting too high max speed seems to be a possibility.
Your photo just showed up. I notice the part number on the board is MAXNC CL 10108C. The circuit diagram is for 10108A. I don't see any obvious differences in the parts used, maybe the PIC program is the difference.
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I'll start with 2500mm/min for Z in Motor Tuning.
I still have MaxPath42, which seems to be a MaxNC renamed Mach3 version R3.033. I'll reinstall it and see if it makes a difference. Might make the A channel work.
Yes, the actual board is a 10108C, not A, but I looked for differences and could not find them.
As it is almost impossible to read the part numbers on the .doc, I could not verify if there had been a part update.
I have not been able to find a circuit diagram for my C model.
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I re-installed MaxPath42 software (Mach111 version R3.033), copied the license into the C/Mach111 file, rebooted and opened the software. Made the X/A axis pin changes to Config - Ports and Pins - Motor Outputs updated the values in Motor Tuning, saved everything and for luck's sake rebooted again.
Turned on the CNC, started the software (also did this in reverse in different trials) and tested the motors by jogging.
The X gantry does not move but the Zero X DROs change values as if movement is taking place.
The Y and Z motors move the gantry all but a few centimetres before the error 'Limit Switch Triggered' shows and the movement stops, even though no physical limit switches were triggered.
I'm at my wits end.
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Should any of the config tabs with A axis values be updated now the A channel is used for the X motor: Input Values, General Logic Config - Angular Properties and Active Plane of Movement, Motor Home and Soft Limits?
Also, there are other references to the A axis in MaxPath42 and Mach 3 that seem quite fixed; so can I actually use the A channel to drive the X motor?
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sorry, was off a few days.
can you pls post the actual XML file, will have a look tomorrow.
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This was the last Mach3 xml before I re-installed MaxPath42
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This was the last xml after MaxPath42 (Mach111) was installed
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Hello again people, Dave from Lin Engineering said that the stepper is especially manufactured for a flexible hose company. I looked into what flexible hose companies require steppers for and found they use them for peristaltic pump manufacture. I looked for pumps with a similar winding resistance to mine and found that many of these pumps have a recommended speed of 0-600 rpm
So I'll play it more cautiously and set the X and Y speed at 500 and the Z speed at 625
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Stuffed that one up.
For X and Y axes say 500 revs/min equals 500 x 200 = 100000 steps/min equals 100000/39.37 steps/mm = 2540 mm/minute.
For the Z axis: 2540 plus 25% = 3175 (31.25 steps/mm)
I'll leave them at your suggested settings of 2000 mm/min for the X and Y, and 2500 for the Z axis, nice and safe.
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ok tryed to find an answer for the question:
why are we not able to run X-axis on the A channel?
here is the answer: https://www.machsupport.com/forum/index.php?topic=202.0
sorry did not know about this.
that means you have to get the X-channel back working.
i would start with the Change of the DM7400N, maybe the burnt TP120 has also destroyed the Output
of the DM7400N.
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Thanks TPS, good to know we're all still learning. I'll reset the pins first in MaxPath (MaxNC Mach111) and do a trial run, then I'll re-install Mach3 and see what the difference is.
The Y and Z axes were running much better in Mach3 than MaxNC Mach111.
I'll report back once that is done.
Then, if there are further X axis problems, I'll try to replace the DM7400N
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Both trials with MaxNC Mach111 and Mach3 were unsuccessful for the X Axis. The problem is the circuitry. as all motors work well on the Y or Z channels apart from Limit Switch issues
I have decided to call it quits with this circuit board as the actual board is also damaged with the first Capacitor replacement.
It also seems that other people have had similar problems with MaxNC circuitry ...... no wonder MaxNC went bust.
I've been flogging a dead horse now for some 10 months and it has been enough.
I want to have a CNC that actually works.
I'll start another post with the question: does anyone know of a good but not too expensive DIY contoller/driver for either my existing or new motors
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If you want to stay on cheap side, buy TB6600 drivers and 5 Axis Mach3 breakout board (LPT) in well known Chinese supermarket.
My homemade CNC ruter has that configuration and cost for the above was cca. 40€. Add ti that a power supply and you are good to go.
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ZASto, I'm an absolute newby feeling my way blind in the dark.
Does this configuration support encoders and limit switches, and does it have good installation guides?
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Encoders for what purpose?
Parallel BOB: https://www.aliexpress.com/item/32955122211.html?aff_platform=portals-tool&aff_trace_key=c4172a430fe64741bab993f937ba5642-1606473628831-00379-_ePNSNV&tmLog=new_Detail
TB6600 stepper driver: https://www.aliexpress.com/item/1005001493127765.html
Mach3 running on a bit older computer with Win XP, or as a last instance Win 7 32-bit
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To answer your configuration question about encoders, most hobbyist CNC machines are open loop. They don’t feed back the position to the controller with encoders.
The equipment ZASto suggested should be a bit better that what you have but has little extra for adding more features. Also you will need a power supply for the steppers. The stepper drive photos show they can use 9 to 42 volts. The higher the voltage, the more torque and speed you will get from the motors.
Here are a number of things to consider before you select your new equipment. I am including features you may want in the future. There are many posts discussing
specific pieces of equipment.
Type of Interface to PC BOB
Parallel - 1 port, limited number of Inputs and outputs.
USB, Ethernet - Multiple ports, some have an External motor controller
http://support.machsupport.com/en/kb/articles/what-is-an-external-motion-device
Electrical Isolation from the PC protects circuits from damage and interference. Isolation between the interface and the steppers and spindle is important too. The drives in ZASto’s link are optically isolated.
Many interfaces need a power supply, usually 5 volts.
Equipment to be interfaced
Limit and home switch inputs – more IO ports allows separate input of switches to help with troubleshooting.
E-Stop input
Stepper motor drives
Relays for Spindle On/Off - direction, Coolant, etc
Analog output for spindle speed
Stepper motor drives
Motor current, speed
Stepper motor power supply
Current setting for your steppers – we will need to determine that later
Optional equipment
Probe – set tool height
MPG – manual pulse generator to manually move the axes
LASER
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I have looked at the specifications for motors with a the same frame size and similar holding torque and resistance. Their amps/phase is around 2 to 2.5 amps. If you apply too much current the motor will run hotter and the magnetic field will saturate give you no further improvement in performance. Too little current will reduce the torque but still be much better than the current system.
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Hello again MN300.
You speak from an assumed level of knowledge that I do not posses. This is fine by me, but that requires much research and homework on my part just to understand your terminology. To do so successfully, I would be asking quite some questions to consolidate my understanding and would like to have them answered individually, otherwise I'm left hanging ... that basically means mentorship on you part; would you be willing to do that?
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Just to get my mind straight:
The 'Interface' is the device that is connects the 'Controller' to the computer via a parallel port, USB or ethernet cable, such as a BOB.
The 'Controller' is a collection of devices (hardware) that comprise circuitry that facilitates functions such as:
Limit and home switch inputs – more IO ports allows separate input of switches to help with troubleshooting.
E-Stop input
Stepper motor drives
Relays for Spindle On/Off - direction, Coolant, etc
Analog output for spindle speed
Probe – set tool height
MPG – manual pulse generator to manually move the axes
LASER
and there are 'Power Sources'.
Both the 'Interface' and the 'Controller' hardware has to be built to allow particular software such as Mach3 or 4, or any other chosen software.
The Computer, Power Sources, Interface and Controller have to be electrically isolated. In fact, there are Interface and Controller components and parts of their circuitry that should not have a common current flow. 'Energy or information can still be exchanged between the sections by (other) means such as capacitance, induction or electromagnetic waves, or by optical, acoustic or mechanical means' (wikipedia), and these 'means' are built into all the devices.
I would like to maintain all the functions my CNC has at present, inclusive of MPG, as a minimum. I'll also keep my motors and their Encoders as they seem to be working well at present. My router does not have a coolant facility, but who know, might need it in future.
Please advise which Windows O/S would be most stable for Mach3. I presently run on Vista, but maybe another would be more stable?
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Just to tangle the strings a little bit :)
Controller is, in case you are using parallel port, your computer running Mach3 or similar software which generates Step/Dir signals. In case you are using USB or Ethernet devices, these are controllers as they are generating Step/Dir pulses derived from data that your computer sends in form of PVT (Position Velocity over Time).
BOB: in case of parallel port, a dumb piece of electronic circuitry for interfacing between parallel port and motor drivers and various switches (Home, Limit, Probe, ...). In case of USB/Ethernet, those controllers are BOBs at the same time.
Mach3/4 are open loop controlling programs so you can not use encoders that are mounted to the motors.
If you want to use MPG with Mach3 without external controller, you will need a second parallel port and some "brains" to be able to use it (I do have it on my machine).
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Strange thing is, ZASto, The original circuit board fitted between my computer and the CNC has encoder plugs and the encoders were plugged into them. If you go back a few pages on this post you'll see the circuit diagram. Are you telling me that Mach3 made no use of that info, or that the encoder info was not fed back within that circuitry to fine tune the stepper to prevent stalling? I'm so confused.
Also, my 6 wire motors are configured into a 5 wire Unipolar manner. Should I change the wiring config to Bipolar? And should it then be series, half coil or parallel? I have to fully understand these concepts first to even make a choice.
Could you send a labelled diagram of your set up and all the functions it provides to the CNC? I need some visual input.
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-in your Special case (MaxNC controler board) the PIC is reading and handling the encorder, and only the PIC,
Mach3 knows nothing about this Encoder.
-in a good tuned stepper System it is normaly not necessary to use encoder's
-anyhow there there are stepper Motor drivers on the market witch can handle Encoders. then they are
closed Loop. Leadshine is only one example:
http://www.leadshine.com/ProductSubType.aspx?type=products&category=closed-loop-steppers&producttype=closed-loop-stepper-drives&subtype=general-closed-loop-stepper-drives
but also here, only the stepper drives reads/handles the Encoder, not Mach3
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Thanks for the link TPS
I have just found 'CNC Router Source' - http://www.cncroutersource.com/homemade-cnc-router.html and will read my way through that. Seems to give a good overview of all the control and driver criteria.
ZASto's set up seems simplicity itself and I do like simplicity. I just have to come to terms with my 6 wire stepper motors, their technical specifications, whether or not to use them as a uni or bipolar setup, if bipolar then series, half coil or parallel or even if I should totally replace them; whether or not to use the encoders and how to connect the limit switches and router / spindle. I also have to decide if I want the option to install some extra functions in the future, as MN300 suggested. Will I update Windows, and if yes, which Mach version would be the best to use on that O/S; will I use the parallel port, USB or an ethernet cable; will I use the computer as the main controller or use an external controller etc. etc.
Cost will determine most decisions but I need to first educate myself.
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The CNC Router Source was a good find!
Yes, simple is good. It will get you running and give you the experience to decide what to do next.
The stepper drives in ZASto's earlier post look like good value for money but I would do further research before committing to the no name breakout board. The chinglish description in the AliExpress site is hard to interpret. Compare that information to the manual for a similar BOB.
https://www.cnc4pc.com/pub/media/productattachments/files/c11g-r9_user_manual_2.pdf
If ZASto has used it and can support you then it sounds like a suitable device. Does your computer meet the requirements for using that board?
The stepper drives are for bipolar motors. Ignore the center taps on your steppers and connect the ends of the windings to the drive.
We need more information to decide if/how the breakout board can control your spindle. The picture of the breakout board shows a relay but I would hesitate to run mains power through it. Does the spindle have a variable speed drive?
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The BOB that I use is perfectly suitable for a beginner and intermediate user.
Nothing special on it. It has a possibility to "control" 5 stepper motors or 4 motors + spindle.
As you can see from schematic, if jumper is placed on dedicated pins it controls the relay which can be used for switching spindle On/Off. PWM is available at the terminal P1 buffered from pin1 of LPT port and as 0-10V at dedicated output near relay output.
So it is Mach3 that controls spindle THROUGH BOB ;D
Another thing, this BOB needs two power supplies. One 5V connected to PC 5v and PC GND and a second one, 12-24V (if stepper supply is not higher than 24V it can be used), for input side (Home/Limit/Probe).
Chinglish? Attached manual is quite easy to understand.
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Thanks to ZASto for providing the missing documentation. I looked for links in the AliExpress item but could not find them or a model number with which to search the web.
It's good to see the 12 to 24 volt side of the circuit is isolated from the parallel port. This includes the 12V switch inputs, the relay common, and the 10V analog output. The TB6600 stepper drive is opto-isolated completing the isolation between the parallel port and the rest of the CNC controls.
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I use the same BOB with Mach3 and with Arduino running GRBL (when playing with 2.5W laser module). Just unplug cable from LPT port and plug it to Arduino BOB that I made.
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Thanks for all your input, people.
My computer is a ACPI x 86, 2 x Intel(R) Core (TM) 2CPU 4300 @ 1.8GHz each. Memory a paltry 2046MB. It runs Vista, which during it's time was regarded as a giant virus.
I can install XP if that would be better.
My router is a Bosch 1617 EVS, 120V, 60Hz, 12A and 2.25HP. It's power supply is a stepdown transformer 240 to 115V. The Router was supplied with the CNC and US rated. So was the CNC. It is a variable speed but manually controlled
I now have the opportunity to gear control componentry to 240V mains.
I have looked into the TB6600 steppers and ST-V2 BOB. The BOB is regarded as one of the 5 best for Mach3 while the TB6600 presented quite some problems in the early 2010s. Problems such as overheating and not supplying the rated current. That seems to have been resolved but it still seems to be a case of buyer beware of cheap imitations.
BUT, I've committed and bought the stuff from a reputable Oz supplier.
?What is a jumper and a PWM? I looked it up online but could not find a ref as to what they actually are, only that the are used.
So now I wait till the goods arrive.
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A jumper is a short wire or clip connecting two point of a circuit. They typically enable or disable functions or set the configuration. The jumper in the BOB diagram enables the signal on the port pin 17 to operate the relay as opposed to providing a digital output.
PWM is pulse width modulation. The off and on time of a constant frequency signal is varied to encode an analog value. It's a way to transfer a numeric value using just one output. In the case of the spindle speed 10% on time is converted to 1 volt output, 50% = 5 volts etc.
Did you buy the power supplies?
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Good to know.
No, I have not yet bought the power supplies. I have a shed full of those little AC/DC adaptor transformers that power TVs, amplifiers, laptops and a variety of other electrical devices that I thought might be suitable - could be mistaken. I have here for instance a Toshiba N17908, AC 100V, 50-60Hz, 1.5A to DC 19V, 4.74A, or a Simsukian with an output of 9V DC and 1.5A .... would that be a suitable approach, and what Voltage and Amperage parameters should I look for?
By the way, could the Bosch router speed potentiometer be replaced by another devise that can be activated by Mach 3?
So I will be running the steppers in an open loop config, without encoders; should I expect missing step and stalling difficulties and what should I do to minimise or eradicate the chances of these happening?
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As ZASto lives in your part of the world (Vanuatu) he can better recommend a local supplier for the stepper supply. I'm 17 time zones away from you, GMT-6.
The presence of a USB type connector on the BOB for the 5V power indicates it's expecting the type of small supply you mentioned. Just make sure it's 5V.
You may want to purchase a cheap digital multimeter. Once you learn a few basics it will be useful for setting up and trouble shooting.
I would have to see information about your drive to know if it's possible and is it's safe to connect it to the BOB. The relay and analog output share a common with the switch inputs. The drive could put a hazardous voltage on the switch wiring. There is equipment you could add to isolate the drive if that's a goal.
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The BOB purchased is the ST V2 and the Drives purchased are the TB6600 and I've purchased a digital Digitech multimeter to play with.
ZASto, would you please tell me what power supplies you use to power these devices?
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@MN300: Actually my TimeZone is GMT+1 :)
To be on topic, PC side supply can be a simple USB cable from computer connected to USB connector on BOB.
The other power supply depends on your motors. I use 24V / 240W MeanWell switching power supply and on PC side 5V 15W also MeanWell power supply. I prefer a separate power supply for 5V side.
Power rating on 24V side is determined by your motors and oversized supply will be happier when it is not loaded 100%
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ZASto, Sorry for misplacing you. Your profile lists your location as Vanuatu. Google maps puts that in the South Pacific near Australia.
Your power supply selection sounds good. Four motors (who knows the future) times 2 windings = 8 windings. 3 ohms times 2.5 amps squared times 8 = 150 watts. I would expect the actual motor current to be less.
Sherwood, Here is a bit of explanation about the magic the stepper drives do. If you add up the motor currents, 8 times 2.5 amps, you get 20 amps. A 24V/240 watt supply can only provide 10 amps.
The system works because the stepper drive contains a switching power supply that efficiently converts the incoming voltage and current to whatever is needed to establish the selected current.
At the maximum expected current setting, when the drive is stopped, the voltage on a winding will be 7.5 volts.
Voltage = 2.5 amps times the resistance 3 ohms. (both sides of the 1.4 ohm halves plus a bit for wiring loss).
In this example the output of 7.5V at 2.5A (18.75 watts) is converted from an input of 24V at .78A (18.75 watts).
Actually the conversion is probably 80% efficient so the input current is closer to 1A. Times 8 windings = 8 amps from the 24V supply.
When the drive is stepping the current changes with each step. When the inductance of the winding sees a change in current it creates a back voltage which resists that change. The drive momentarily raises the voltage applied to the motor to overcome this and speed up the rate of change. 24V is about 3 times 7.5V so the current rises 3 times faster. Motor torque is related to current so this allows a motor to have more torque a high speeds.
My max current estimate of 2.5 amps would produce a lot of heat in the motors. Your system should run well at 1.5 or 2 amps.
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Yep, I follow the formulas mathematically; conceptually somewhat hazy but that will settle.
What do you think of some of the cheaper ebay transformers from China at about AU$20 to $25. I bought a 240 - 110V step down transformer from China quite some time ago and it's still working.
Also, the 5V power supply, any particular wattage to consider?
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You seem eager to learn but was my mention of stepper magic too much, too soon?
I think the BOB will draw less than 250mA (0.250A) from the 5V supply. A USB 1.0 or 2.0 port can provide up to 500mA.
While checking the manual for info on this issue I noticed they show the 5V USB jack connecting to the computer. I don't see a reason that shouldn't work if there is a spare port.
Any small power supply intended to emulate a USB port's DC will do the job too.
The 24V power supply is not a place to cut corners. ZASto has suggested a supply known to work, best to stick with that.
Most power supplies these days will accept AC mains voltage from about 100V to 240V. There should be no need to involve a stepdown transformer.
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Yes MN300, challenging
As far as the stepper electronic magic is concerned, I'm reading and comprehending more.
I see how you arrive at all the values. I see how the 24 V power source sets up the stepper winding's potential energy (PE) and how the stepper drive is basically a switch that raises the PE levels (Voltage) required to start the Flow of electrons (Amperage) to generate the Power (Wattage) required to rotate the stepper motor 1 step at the time.
Question: Was the 2.5 Amps per winding or per motor (2 windings)?
Question re: "When the inductance of the winding sees a change in current it creates a back voltage which resists that change" How does that occur, is that an opposing electromagnetic force?
I'll have a good view of the entire process depending on the answers to those questions.
I'll provide the 5 V and 24 V of the BOB with a reliable separate power supplies.
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This tutorial covers back EMF and the relationship of current and voltage.
https://www.electronics-tutorials.ws/inductor/inductor.html
Stepper current is specified in amps per phase (winding)
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I have been looking at how the BOB board connects to the rest of the system and see a problem with the stepper drivers. The TB6600 stepper drivers have opto-isolator inputs. The input signal current is a minimum of 8 mA. This is far more current than a normal logic input would require. The signals from the parallel port are buffered by SN74HC245 Octal Bus Transceivers. The datasheet says the output current of that device is 7 mA. That’s not to say it can’t provide more, but the voltage out may be lower than the level that is guaranteed to work with the input of other logic ICs. While this may be marginal design my main concern is with the enable signals.
Unlike the other signals, the enable signal, Pin 14, connects to 3 buffers. There are five 4 pin connectors provided for connecting to the stepper drivers. X and Y are connected to one output, Y, A and B are connected to the second. The third output goes to the P14 terminal. If the 4 pin connectors are used as intended the output shared by X and Y will have to supply 16 mA. As there is no A or B, the Z axis doesn’t have to share.
A solution would be to connect the enable of either X or Y to the Pin 14 terminal.
Another alternative way to wire would be to use the P terminals. The step and direction signals, P2 to P9 plus P16 and P17, also appear on the terminal strip. The 3 stepper drivers could be wired to the terminal strip instead of the 4 pin connectors. The driver enables would connect to P14 and the enable pins of the X (or Y) 4 pin connector and the Z connector. I think the connectors advertised as DuPont connectors would fit onto single pins of the 4 pin connectors. Many hobby sources carry these. Here is an example.
https://www.ebay.com/itm/40pcs-Dupont-Male-to-Female-10cm-Jumper-Wire-Connectors-Lead/254793576268?hash=item3b52e16f4c:g:bPAAAOSwASBdJbQJ
This method also gives you a way to connect if the mating 4 pin plugs do not come with the BOB.
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HC245 are very happy driving TB6600 drivers, I had 0 (zero) problems with them.
Don't look at the voltage levels, optocouplers in TB6600 are not logic gates. LED on the input side of the optocoupler is an "animal" that is fed by current, not voltage. Usually nominal forward voltage for these LEDs is around 1.2 - 1.3V.
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Good tutorial, thanks
I'll let you two come to terms on the issues raised by MN300, in the mean time I'll read up on the componentry and processes mentioned.
If necessary, could always obtain a more suitable BOB.
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I can't argue with your successful use of the BOB board. As I said, the IC specs define use in a logic system and the IC will put out more current if overloaded. It would be interesting to know the actual voltage being delivered to the opto input or better yet the current.
Hopefully the designer of the stepper driver left a safety margin between the minimum current that will just trigger the input and the minimum operating level in the spec. I don't have the information to decide if you are operating in the area between or are over the 8 mA minimum.
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Once I have the items, will I be able to provide you with the voltage and current to the opto input?
So you are saying that the BOB IC (is this the SN74HC245 Octal Bus Transceiver?) needs to put out more current than it is rated for, to bridge the communication gap of the TB6600 opto coupler. So if I connected them as ZASto does, what is the worst that could happen, BOB blows up or TB6600 blows up ....... or both??? What damage could occur if the BOB IC was overloaded??
Do either of you have circuit diagrams of both the BOB and the TB6600? If Yes, could you attach them? I'd like to follow the processes.
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Better information may come with the items but I wouldn't count on it.
If damage were to occur it would be to the SN74HC245. Another possible problem would be if the opto-coupler is just barely being turned on. Then it would be more susceptible to noise and could be the cause of missing steps. Since there is an unused buffer why not use it?
ZASto has provided the information for the BOB in a previous post.
https://www.machsupport.com/forum/index.php?topic=43939.msg282588#msg282588
Here is what I found for the TB6600.
https://www.mcielectronics.cl/website_MCI/static/documents/TB6600_data_sheet.pdf
Have you planned a clean place with good ventilation to mount the new equipment?
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Can the voltage and current be measured with my you beaut QM1529 Digitech multimeter?
Since I won't have encoders attached I'd like to reduce the chance of missing steps in every way.
How would you see the TB6600s hooked up to the BOB, your before mentioned 1st or 2nd alternative?
If afterwards it somehow caused an issue, I can always connect the units as ZASto did
Suitable equipment location is available
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Well, I use this BOB for years without any glitch.
We can widen this discussion on "are parallel port electronic components capable of driving opto couplers", but please don't do it.
My first BOB was without any buffering, LPT pins directly connected to optos in motor drivers and switches connected directly to LPT pins.
That was in early days me dealing with CNC.
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Good to hear from you ZASto, I have no doubt that you have not experienced any glitches.
Being the adventurous type, I would not mind trying it as per MN300's suggestion, but any difficulties and I'll default your way.
From the BOB circuitry diagram you attached some time ago, it seems to my untrained eye that the BOB has 6 opto couplers and the diagram states that they are for pins 10, 11, 12, 13, 15 and the 6th for the spindle control maybe?? What is the significance of that as related to using pin 14?
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Pin 14 is one of the buffered outputs, no different from the others except that it is used to control more than one device. Here is a description of the BOB that might be informative.
Pins 10, 11, 12, 13 and 15 are the inputs for the limits switches or whatever you chose to connect to them. The switches are powered by a 10 volt supply regulated down from the 24 volt supply. Their connection to the parallel port inputs is isolated through 5 of the opto couplers.
The 6th opto coupler connects pin 1, an output from the parallel port, to the circuit that changes the PWM spindle signal to analog. In the BOB diagram just to the left of the 6th opto-isolator there are two triangle symbols. These the sections of the SN74HD245s that buffer pin 1. Those sections and the 10K resistor are also shown on the left side of the diagram as IC2 and the resistor attached to pin 1.
Other outputs from the parallel port are not opto-isolated by the BOB. They are buffered by the SN47HC245 ICs and connect to the terminal strip. Stepper signals also connect to the 4 pin connectors. The opto couplers in the drivers isolate them from the parallel port and the 5V supply.
Pin 17 can be jumpered to operate the relay. That circuit is on the middle right of the diagram. The resistor and SN74HC245 section are also shown on the left like the analog circuit. The relay common is shown connected to the 24 volt common. That seems a bit strange as relays are often used to isolate circuits.
The relay, the input switches and the analog output share the same common which is isolated from the parallel port, the buffered outputs and 5 volt common. The parallel port receives ground from the PC. The 24 volt common should be separately grounded for safety, especially if the connections to the limits switches are not protected.
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Here is a start on a wiring diagram. We can improve it when we learn more about the power supplies and any features you want to add. If you decide to use the 4 pin connectors instead of the terminals for the stepper drivers I could revise it for that.
I couldn't see the legends for the BOB relay terminals in the available information. Also it would be useful to verify the relay common is connected to the 24V common.
If the stepper motor windings are run in twisted pair and kept well away from the other wiring it will greatly reduce the change of problems with noise. Of course the spindle motor wiring need to be separated too.
https://audiouniversityonline.com/twisted-pairs/
The 10 volt powered opto-isolated inputs give you better noise rejection than the usual 5 volt BOB wiring.
If the four wires to the stepper driver inputs are twisted together that will reduce noise pickup too.
When you decide where to mount the new equipment you will be able to determine if longer wires will be need.
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Thanks for the road map to the circuitry, makes what I'm seeing more meaningful.
Twisted pairs are good, follow the reasoning from the link
I will have to dismantle the harness as there are now encoder and central tap wires in it that will not be used. Should I remove the encoders from the motors?
All other motor wires will need to be extended by 50 cm to 60 cm, will that affect information travelling between the motor and control?
I'll follow the 'User Manual of 5 Axis BOB' wire attachment with the MN300 alteration. How do I identify Stepper Pulse and Direction wires?
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Did you draw that circuit diagram MN300? :)
You could make a tute out of the sherwood cnc saga; must be plenty other newbies who would like to install ZASto's combo.
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The drawing was made with the classic version of ExpressPCB software. I've used it for well over 10 years to design PCBs.
Let me discuss the most rigorous method of wiring. To get some idea of cost I found an eBay site with cable that looks to be a reasonable prices. This is just to get a general idea and not a recommendation. I know someone who bought inexpensive cable only to find out it was copper plated aluminium and not suitable for his use.
https://www.ebay.com/itm/RVSP-2-4-6-8-10-12-14-16-20-Core-Double-Twisted-Shielded-Cable-485-Signal-Wire/254397336055?hash=item3b3b4349f7:g:JE8AAOSwgqZdrqCW
Motor wiring would be done with shielded 2 pair cable.
4 core 0.5 mm2 5 meters US $13.30
Stepper drivers would be connected with 3 pair shielded cable, one pair for each of the three optos.
6 core 0.2 mm2 5 meters US $11.02
Limit switches would be connected with twisted pairs, individually shielded or grouped into one cable as the physical configuration requires.
More of the 6 core or 2 core 0.2 mm2 5 meters US $5.87
24 volt power would connected with loosely twisted hookup wire to each stepper drive from a distribution terminal block. This is because if they were daisy chained the first part from the supply would be carrying all the motor current and need large conductors. I should change the drawing to reflect this.
There would be many commons and shield grounds going to the same places. On a industrial machine we would use lots of terminals the cost of which adds up fast. For hobby use they could be spliced together. You may have to learn how to solder.
This is a a belt and braces approach to the job. You might get away with extending the existing wiring with whatever scraps of wire you can find but...
Short runs need less protection so you may not need the expense of all that shielding but I don't know the details of your mill. I'd like to hear about the mill and what materials you have on hand. Who are the reputable vendors in your part of the world? Can your friend make recommendations?
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Here is item I forget to mention. If your E-STOP switch has two contacts we should use one to interrupt the 24 DC to the steppers.
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Prep time, OK;
I'll use the 4 pin connectors instead of the terminal, I've decided to use cable, I know where I will install the equipment and will measure the cable length required for the Motors, the three TB6600s, the Limits Switches; I'll use a terminal block to connect the three TB6600s to the 24 V power supply. I do not have an E Stop switch
I will visit Jaycar electronics to purchase the lot. If they do not have it I'll source it online most probably from Maker Store. The E Stop shall have 2 contacts.
I have been soldering for a few decades now but will purchase an iron or tip that will allow for finer work.
The CNC mill is a basic set up; table, X,Y and Z gantries with lead screws directly attached as extensions to the stepper motor shafts. It has two Limits Switches for each axis. I have no relay and the Bosch motor/spindle is mains connected, and only has a manual dial RPM potentiometer built into the router casing. It has a 3 pin plug - mains earthed.
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Here is a second draft of the wiring diagram.
Stepper input signal wiring changed to use the 4 pin connectors. Do you have a place to buy the cables or the materials?
Second limit switches added.
Wires grouped to indicate cabling.
Second E-STOP contact used to break AC mains to the 24V supply and the spindle.
Optional Relay added to start and stop the spindle under MACH control. The selected relay has a test button so the operator can run the spindle manually.
I would prefer to use a major supplier for some parts like the relay and socket. Minimum order value or minimum for free shipping might make that impractical. Candidates are element14, Mouser and Digi-Key.
Maker Store may have the best price on cable but one item has aluminium conductors, others don't specify. That's something to check before ordering.
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I'll cost all the required items from the 3 suppliers you mentioned; they have good Aust online stores so all good.
Had a look at the E Stop switches and was surprised by their cost Aus $ 50 to $300 and more.
Will discuss item specifications with you prior to placing the order.
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Wow :O Are those switches made from outback gold nuggets?
https://www.aliexpress.com/item/4000184386889.html?aff_platform=portals-tool&aff_trace_key=0036ea43b7c74e19a3a4f66000fae4eb-1606981590519-06439-_dVh6yw5&tmLog=new_Detail
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I'll cost all the required items from the 3 suppliers you mentioned; they have good Aust online stores so all good.
Had a look at the E Stop switches and was surprised by their cost Aus $ 50 to $300 and more.
Will discuss item specifications with you prior to placing the order.
Hey Sherwood, fellow Aussie here. Cairns, Nth QLD.
I've been watching this topic but haven't waded in because you've been getting an amazing amount of input from others.
I just thought I'd chime in and direct you to the Emergency stop switch that I use on my home made router.
https://www.jaycar.com.au/latching-emergency-stop-switch/p/SP0786
It can be set up as NC or NO contacts.
Not sure if anyone has mentioned this before, but I'd also fit a 0.1Uf capacitor across each of your limit and emergency switches.
This solved an electrical noise issue that I and some others have had with our set ups.
https://www.machsupport.com/forum/index.php?topic=26182.0 (https://www.machsupport.com/forum/index.php?topic=26182.0)
These guys might be of help to you.
https://core-electronics.com.au/search/?q=0.1uf (https://core-electronics.com.au/search/?q=0.1uf)
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0.1 uF caps are not needed if switches are NC.
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Wow :O Are those switches made from outback gold nuggets?
Parker Schnabel and his Team is coming over to mine the Gold for the contact's. .)
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With ZASto's combo and MN300's rumba; how can I loose. I've come across pure talent here.
Thanks for the info fellas, will lob into jaycar with the purchase list as well. Save myself some money but won't forget the copper plated aluminium.
I'll check to see if the switches are NC or NO
TPS, have you just come rolling in from a party, stood next to some guys shrouded by smoke?
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I used to design controls for industrial equipment, $50 for an E-STOP switch would not have been out of line because a switch intended to last for decades of hard use costs money. However we are in the hobby world where things are much more relaxed. If something has crashed or is smoking having the second E-STOP contact to interrupt the power to the motors is not a bad idea. The E-STOP switches found so far have 1 NO and 1 NC contact but we need 2 NC's. Major vendors sell the contacts and the operators ala carte so you can make what you need. At this point the cheapest option might be to buy two and move a contact.
ZASto is quite right about no need for capacitors on NC switches that only open in emergencies. Additionally The 10 volt levels into a relatively high current input (the optos) will be fairly immune to noise. Your machine is small and you should be able to keep power wiring away from the signal wiring. These all reasons you should not need caps.
Here are some cables from Maker Store. Could you contact the store to find out if they are all copper? I imagine they are but aluminium wires that break under vibration would be no fun.
Limit switches - https://www.makerstore.com.au/product/2-core-cable-70-2/
Motors and maybe stepper driver inputs - https://www.makerstore.com.au/product/shielded-4-core-cable/
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It's kind of people not to point out the mistakes in the last drawing. Errors are bound to creep in. All the more reason for you Sherwood to go over it and ask about anything that seems wrong or you don't understand. Also it's amazing how much you forget after a year or two. The more detail we put in the easier it will be to repair or upgrade the system later.
I was going to use a solid state relay for the spindle but decided not to. It would have meant using P17 which is shared with the onboard relay, that's why the relay jumper was OFF. However I'm using the small onboard relay to control the spindle relay so it needs to be ON.
A copy and paste error affects the text for the limit switches. i forgot to go back and change "X AXIS LS" to Y and Z on their lines.
Some items will require more input to finish the drawing.
Details of the power supplies. I have drawn components in as semi-pictorial manner to make them clearer to beginners.
There should be a mains switch. Is there something now?
Verify the BOB relay common is connected to the 12-24V common.
Notes about where to use shielded cable.
Notes about shield grounding points. Generally they go to the ground of the equipment sourcing the signal.
Final selections for motor current and micro-stepping.
We'll catch up with these in later revisions.
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Buying quality is preferred, but Yep, true, in hobby world dreams meet the purse strings.
I looked at the Limit Switches, they stop current flow when activated .... that's NC, isn't it. If yes, it's a little counter intuitive as you can not walk through a closed door :-\.
The cables attached to the motors and switches are "Black Box Corp 6/C Type CMR (UL) c(UL) 75C E116394; is that a suitably shielded cable or best totally replaced?
In relation to the spindle control; I would prefer to initially keep my present set up, which is mains power and manual speed control by adjusting the potentiometer built into the spindle motor casing. I would certainly like to upgrade the spindle control to a computerised one as a future project.
A request for specs to determine quality, for all the required items yet to be purchased has been sent to a few suppliers. Awaiting a reply.
I saw the # X Axis LS and yes, did not understand .... will speak up next time.
I'll give you the specs of items (to be) purchased as they arrive.
What Mains Switch are you talking about, MN300, the wall switch for the 240V power supply?
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A main disconnect switch is turns off all the power when you're not using the machine. For you that could even be unplugging the power cord.
You machine worked at one time so the wiring must have been adequate.
The physical layout of the machine will determine the length of the cables and how hard it will be to keep good separation between the motor cables and the other wiring.
You may be able to reuse the encoder cables for the stepper driver inputs.
I looked back at the photo of the motor cable. It looks like it's 6 conductor unshielded. Buying new cable from Maker Store for the stepper motors shouldn't break the bank.
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?
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OK, it arrived. That's the CNC; didn't know if the attachments would work this time.
Everything associated with the CNC including the computer is run via a dedicated power board. No piggybacking of any sort. One switch to turn it all on and off.
I can suspend the power cable for the Bosh overhead and well out off the way of other cables. The Limit and Motor cables will run through the drag chains, but once they exit I can truly separate them. Variations to the theme will be seriously considered.
Is a 0.4 mm 4 core cable suitable or is 0.5 mm minimum requirement. I'll replace all the cables as then I will not have to splice or fit contacts to extend them. One length of cable from the motors and switches to the TB6600s and BOB. Max length is for the Z axis motor and limit switches; 4 meters each. Each drag chain is approx 1.5 m and the distance from the end of the last chain to the best position for the control is 1 m. The last distance may be whittled down to 0.5 m, but I prefer the more distant position.
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The discussion about 0.1 uF capacitors and limits switches made me think about the noise immunity of an input connected to a normally closed switch, With the switch holding the input to ground it would take a very strong noise signal to cause enough voltage to falsely trigger the input. If the switch is operated the system shuts down and any noise that might get through during that state is of no consequence. This would explain why unshielded limit switch wiring was OK.
That would not be the case for a home switch that might be open during part of the normal axis travel. However you don’t use home switches.
I would still suggest using shielded twisted pairs for the motors when you rewire.
The cables from the BOB to the stepper drivers will be short and can be kept away from the motor cables so in this machine shielding will not be needed there.
This power supply is available from Digi-Key and Mouser. LRS-350-24. They also have the relay and socket on the wiring diagram.
I sketched the main components in CAD and made an arrangement that minimizes wiring and keeps different signals separated. The rectangle I drew around it is 300 mm x 270 mm. The depth needs to be 80+ mm to accommodate the stepper driver cabling. The enclosure you provide should be larger to allow for possible future additions.
A really proper box with an interior panel for mounting the components is a bit past your budget.
https://www.digikey.com.au/en/products/detail/hammond-manufacturing/EJ12146/2568630
Even a plastic version is not cheap.
https://www.digikey.com.au/en/products/detail/bud-industries/NBF-32026/2328539
https://www.digikey.com.au/en/products/detail/bud-industries/NBX-32926/2676759
I’ll leave finding an affordable alternative up to your imagination.
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I follow the noise rationale
Every cable on my CNC is UNshielded. I will replace all with shielded twisted pair cable; as said before - not too expensive.
Pls advise though, is 0.4 mm 4 core suitable for the steppers or should it be 0.5 mm precisely?
The 24V power supply I've ordered is a direct equivalent to the LRS-350-24 but 400 instead of 350W.
Thanks for the layout drawing. I'm installing everything on the outside of my wooden computer hutch. 15 mm thick ply and a further 200 mm away from the nearest computer cable. Should be nil noise. I've decided to put it there as there is maximum chance of air cooling. The system is in a shed, which during summer times hits 42 degree C.
Some questions:
"I was going to use a solid state relay for the spindle but decided not to. It would have meant using P17 which is shared with the onboard relay, that's why the relay jumper was OFF. However I'm using the small onboard relay to control the spindle relay so it needs to be ON".
; I do not really understand this, MN300, where is the small onboard relay?
On the BOB connectors; what do CW and EM stand for?
On the 24 V Power Supply; what do L and N stand for?
Just below is a squiggle with F1 and 2A; what is the squiggle and what do F1 and 2A stand for?
On the 230 VAC; this is mains power, is it not? What does the E stand for?
On the TB6600; what do ENA and VCC stand for?
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Y or N; 4.5 V 500 mA instead of 5 V power supply?
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0.4 mm2 is OK.
What's the model number of the 400W supply?
When the temp gets into the 30's blow air over the stepper drivers. The maximum ambient temp for the motors is 50º C.
In one corner of the BOB photo there is a blue box. That's a small relay that is activated by a signal on P17 when the jumper is installed. I have used it to switch 24V to the optional relay for spindle power.
The different pieces of equipment use different names for the same signals.
DIRECTION = DIR = CW (CLOCKWISE) ENABLE = ENA = EN PUL = CLK (clock) = STEP
L = LINE, the wire that carries 240 volts N = NEUTRAL , The wire that returns the current from the 240 line. It is connected to earth at the source. If it loses that connection to it could be energized by the 240 line through the connected devices and be hazardous. That's why a separate earth connection is used as the safety ground. E = EARTH This line is connected to exposed metal parts to prevent them from being energized if accidently connected to voltage.
The squiggle is a fuse named F1, value shown is 2 amps but that might be increase when I see the supply info.
VCC = voltage, common collector. It's the supply that powers the logic. That's the 5V supply in this case. The name is a carry-over from the early days of logic IC spec's.
No to 4.5V
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Thanks for the answers; illustrative.
24 V power supply from Geekcreit S400-24
I have a 240 V as well as 24 V computer fan; which would be the best to fit, considering 'noise'.
value shown is 2 amps but that might be increase when I see the supply info; by 'supply info' you mean the specs of the Geekcreit S400-24?
5 V it is
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Neither fan should cause a noise problem, use the one that moves the most air.
Yes, the fuse is for the 24V power supply.
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I have been revising the wiring diagram, adding information on the selected 24V supply and some notes. I’m sure it’s not finished yet but I’ll attach what I have so far to help with the following discussion.
Here are some PDF file links for reference.
Microstepping
https://motion.schneider-electric.com/technology-blog/stepper-motor-basics-half-and-micro-stepping/
TB6600 stepper driver manual
https://forum.arduino.cc/index.php?action=dlattach;topic=558523.0;attach=266385
I added notes with suggested starting values for stepper current and microstepping. After the machine is running we can change them to your final settings.
I chose times 4 microstepping to improve the smoothness of the stepping. This decreases the mm/step and increases the steps per second rate from MACH 3 by the same factor. If the higher rate is problem we will have to reduce it.
A more careful reading of the manual revealed my assumption about the ENA input was incorrect. In fact powering that input turns off current to the motor! I think it would be more correct to call it a disable input.
One of the connection options shown is to not connect anything to the ENA terminals. This would leave the current on at all times. The disadvantage of this is that the motor would consume about 40 watts of power in standby. However once the machine is zeroed you wouldn’t want to turn off the current. Doing that would result in the motors pulling to the nearest full step position. Unless you spend a lot of time with the machine powered and idle not using the ENA inputs makes sense.
By the way, this explains why overloading the BOB enable outputs is not a problem. No current is taken from the BOB when the motors are in use. If there is a failure it would be the inability to turn off the current.
I realized a quirk of the BOB board makes it possible to use an E-STOP switch with only one NC contact. The 24V supply powers the opto couplers for the inputs. Turning off the 24V has the same effect as opening the normally closed E-STOP switch. With this method the BOB’s E-STOP input would be wired directly to GND.
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Thanks MN300, I'll pore over the micro stepping article and TB6600 manual.
Drove the distance to Jaycar today, lousy customer service but came back with the following:
E Stop - https://www.jaycar.com.au/latching-emergency-stop-switch/p/SP0786
5 V power supply - https://www.jaycar.com.au/5v-dc-3a-slim-power-supply-7dc-plugs/p/MP3480
Terminal block for 24V supply from BOB to TB6600s
but no cable. "Look in the catalogue" was the reply, at a cost of just under $6.00; so ordered the cables from a very helpful person at Makerstore P/L - awaiting delivery.
Also received by post: BOB and 3 TB6600s. I opened the driver up to see if it truly had a TB6600 chip, and it does.
I'll read up on the ENA in the manual to follow your rationale and I see what you mean re the EStop if it is as per attached pic
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I see the microstepping now. The 1.8 degrees is determined by the number of 'teeth' of the permanent magnet on the rotor, the step is activated by an electromagnetic field in the stator. Direction is determined by polarity with change of direction determined by change in direction of current applied to the stator. Rate and step size of rotation is achieved by playing multiple windings (Min 2) off against each other in terms of current strength, direction and sequence. I'm still to fully understand Phase Current Waveform.
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The power supply you selected has 3 terminals each for V+ and V- , you can connect the stepper drivers directly to the supply. Some of those terminals will be shared with wires to the BOB, also for the relay if you choose to control the spindle. The terminal strip you bought may be useful for other wiring like the AC mains circuits and E-STOP.
Is the cable you ordered for connecting the power supply to the TB6600s?
You stated earlier that you would like to use the 4 pin connectors for stepper driver signals. To do so you need cables with the mating plugs attached. Have you found a source for them or the materials to make them? It would be easier to use the cables from the now unused encoder and wire to the BOB terminal strip.
You mentioned phase current waveform. It can be explained with Trigonometry and vectors. If you graph a vector rotating through 360 degrees you get a sine wave. This is like a stepper motor moving from one pole to the next. The current in one winding would be the sine, the other the cosine. Together the two currents create a rotating magnetic field that pulls the rotor in a circular path. The vector sum of the currents is always the same while as resultant position changes.
https://upload.wikimedia.org/wikipedia/commons/8/89/Unfasor.gif
This animation may help. The sine being generated is the position of the rotating vector in the X axis. If the Y axis position was graphed it would be a sine wave 90 degrees out of phase. These two waves represent the currents needed to make a rotating field.
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Here is another revision of the wiring. Unless you decide to use the BOB terminals instead of the 4 pin connectors it could be the version you will use to wire the machine. After the machine is setup and running we can make the final revisions.
This version uses a single E-STOP contact and does not use the stepper enable signals.
I imagine you will use a power strip to distribute the mains power so I have added that. The spindle would plug directly into the power strip if you choose not to install the optional relay.
Jaycar and Maker Store don’t have the fuses and fuseholders needed so I used element14.
Fuseholder
https://au.element14.com/littelfuse/01500332h/fuse-holder-6-3x32mm-15a-500v/dp/2748639
Fuse
https://au.element14.com/bel-fuse/3sb-5-r/cartridge-fuse-slow-blow-5a-250v/dp/2844478
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The wiring diagram will make the job easy, thanks. I've started stripping the CNC of its harness and am working on the mounting board. I thought I'd mount all components proud off the surface by some 5 mm to allow maximum airflow around the objects ... should help with cooling on hot days.
I have a 5 amp trip fuse, good condition and works with a range of DC voltages, can use that instead of buying a new one.
The supplier for the BOB does not have the female connectors and none are supplied with the BOB, so I'll follow your suggestion and use the decoder cable.
Thanks for the animation, explains a lot
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I have a 5 amp trip fuse, good condition and works with a range of DC voltages
Is your 5 amp trip fuse suitable for 230 VAC?
Attached is a revision connecting the drives to the BOB terminals.
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250V VAC Max
I've attached the LS harness diag, can you make sense out of it?
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I could make some guesses but unless we're trying to reuse those wires I don't see much point in spending time on it.
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I was hoping that the harness might have each axes' limit switches wired in series and able to be hooked up as is, but it doesn't seem to be an in series wiring method. I'll cannibalise the cable for other applications if suitable.
The link you sent me on Nov 30, https://www.mcielectronics.cl/website_MCI/static/documents/TB6600_data_sheet.pdf, states at the end of it's last page that resistors have to be fitted with 12 and 24 V supplies to the TB660, "to ensure control signal current is 8 mA to 15 mA" Does that apply to our use of the TB6600?
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The BOB outputs to the TB6600 come from the 5 volt logic, no resistors required.
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OK, how about the 24V into the TB6600 through connections 6 (VCC) and 5 (GND). That's all fine?
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The 24 volts into pin 6 is correct. It used to power the motor and is also reduced to power the internal logic. The TB6600 has opto couplers to isolate its circuits from the inputs.
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Does anyone sell it on Amazon?
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Hello Ydsccfd, if you're talking about the TB6600, look at the links on ZASto's comment dated Nov 27. They are for a BOB ST V2 and stepper driver TB6600. You'll find some good attachments re those two components from him and MN300 over the last 6 or 7 pages.
I've attached the stepper wiring and colour code jpg, MN300. Would I be right to assume that the Red wire connects to the TB6600 terminal 4, Blue to 3, Green to 2 and Black to 1?
The Limit Switch harness is finished and tested with the multimeter - all good. The switches are connected in series as per your wiring diagram. Still to be attached to the BOB.
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Your motor wire are correct.
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Mounted BOB and TB600s (that sounds sadistic) and wired them to each other. There was no bloodshed. :o
Tomorrow I'll make mounting brackets for the 24V power source I received today and if poss also wire it to the BOB and TB6600s.
Must also make a housing for BOB, thought of a plastic food container just large enough to fit it. Screw the lid to the board, fasten the BOB on the lid and place the box over the top. I'll put some slits in the box for airflow.
There are E Stops between P10 and ground in the Limit Switch array, as well as between the Geecreit and the mains. Will I fit them both or will the 240V one suffice?
I'm still waiting on the motor cable - covid speed.
Hope you and all keep well.
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One E-STOP contact in the mains line to the 24V power supply will do. P10 should be wired to ground which will tell MACH3 everything is OK. When the E-STOP switch interrupts the 24V the BOB will not be able to send ON signals from the inputs to the parallel port.
Rather than just a housing for the BOB can you box for all the components? Either make something or use a large storage bin. Then add large screened holes to the top and bottom.
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Start up notes:
Before applying power double check the wiring, especially the power and ground. A mistake with those can damage your equipment. Mixed up signal wiring will keep the system from operating correctly but is less likely to damage anything.
Set up MACH according to the ST-V2 instruction.
Note: The wiring diagram connects the breakout board and stepper drivers as common anode.
Disconnect the 24V from the TB6600s. Disconnect the 5V wire from the 5V supply to the BOB.
Power on the system and check that the wire from the 5V supply measures +5V to the BOB PC GND.
Turn off power and connect the 5V supply.
Turn on power and use the MACH3 diagnostics to verify the limit switches work. The E-STOP input should trip when the E-STOP switch is pushed. Power off when done testing.
Connect the 24V to one TB6600. Set its switches to
Microstep = 1 S1 = on, S2 = on, S3 = off
Current = 1.5 S4 = on, S5 = on, S6 = off
Power on and immediately measure the voltage on the motor windings.
One winding will have 4.5 volts from the - to the + terminal. The meter may show either polarity. (4.5V = 1.5A times 3 ohms, the total winding resistance.)
This test shows the switches are set correctly. It’s sometimes hard to be sure which switch position is off or on.
Turn power off and connect the 24V to the other TB6600s. Set the switches as shown on the wiring diagram.
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Still waiting on the stepper cables, everything else installed, wired up and tested. All voltages as per expectations, nil flame and nil smoke.
I set the microstep switches and tested B-B+ and A-A+ voltage as 23.8 V. I do not know how that translates once the steppers are connected.
The computer has not been attached to the BOB as yet;
Question: should I at this stage, or wait till the steppers are attached.
I have set the Mach3 values as per the BOB User Manual.
Question: As I do not have spindle control, should I 'Disable Spindle Relays' under 'Config' - 'Ports and Pins' - 'Spindle Setup'?
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You may connect the computer, the limits switches can be checked with the MACH3 diagnostic screen.
In fact you can run commands with the MDI or even G code. It's an open loop system so it won't miss the steppers.
The PUL signals should read 0 volts from their plus to minus terminals when there is no motion. It might be easier to get the meter probes on at the BOB terminals, That would be from the PC +5V to the PUL output for each drive.
The DIR signals can be checked too, they change with the direction the steppers are told to move.
You don't need the spindle but if you enable it you should see the LED on the BOB light and hear the relay click. Then you'll know it's ready if you ever want it.
The full 24 volts on the motor terminals is expected when nothing is connected. When the motor is connected the voltage will be the current times the resistance. 1.5A times 3 ohms = 4.5V This is assuming you have set x1 microstepping. At others setting the current changes with the position.
I don't see E-STOP wiring in the photo, I assume that's coming or somewhere out of view. Turning off the 24V should signal E-STOP to the PC, one more thing you can check now.
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I'll do all that and follow your leads
The E Stop is wired under the board, between the board and the plastic container floor - pic attached
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Connected all components, finalised Ports and Pins setup and looked at the following:
Voltages across Pul+ and Pul-, and Dir+ and Dir- are 4.7 V on average. So does the system senses that there is motion? An incorrect setting or something?
In Mach3 Diagnostics 'Time in int' under the 'Jog On/Off' button rolls from 5.2 to 7.8. I do not yet know what that means.
The Z limit switch inputs do not register; will have to examine the connections from switches to BOB.
X and Y register as expected
X cable still in transit.
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We wired the TB6600 as the ST-V2 pdf showed, that's common anode wiring. Did you check the boxes for Dir Low Active and Step Low Active as shown in the Motor Outputs diagram?
Did you try to change the DIR signal by using the MDI or JOG to run the motor in both directions?
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Yes, all boxes ticked for common anode under 'Motor Outputs'
Jog signals functional by hot keys and onscreen jog device. Have not yet tried MDI but will.
My shed's power has shorted after 3 days of constant rain finding its way through a leak in the shed's tin roof and into the wiring. So no electricity being used there at the moment and the project is at standstill for as long as it takes to safely turn the power on again. Then fix the leak.
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Let's trust the ST-V2 documentation. The TB6600 DIR and PUL inputs are likely reversed the same way the ENA was.
Too bad about the leak, I hope it dries out soon. There was about 1/2 inch of snow here yesterday.
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What could result from such a reversal, real time direction contrary to coded direction?
Really enjoying the rain after some 6 years of drought and fire but must first find the leak to fix the leak. It's a very slow drip that follows the rafters from somewhere.
A white Christmas this year?
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Reversal of the DIR would result in the motor running the wrong direction. That's not a big deal since the direction is easily swapped and depends on the mechanics of the system anyway.
The TB6600 steps the motor on the leading edge of the CLK pulse. Its minimum CLK pulse width is 2.2 microseconds. If MACH3 outputs a 5 microseconds pulse and the signal is reversed the trailing edge becomes the leading edge to the TB6600 and the step happens 5 microseconds later. I think you could live with that much delay.
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All NC limit switches (L/S) working, M1=X, M2=Y and M3=Z. They registered in Mach3 Diagnostics with the LEDs continuously lit. The LEDs would switch off only when a L/S was activated, i.e. circuit opened. And then all at once that reversed. Now the LEDs light up only if the L/S is activated .i e. circuit opened. Is this normal or did some current reversal take place in the BOB?
Should the Mach3 'Diagnostics' 'Output 1' LED light up. How could I test normal output signals.
Still waiting on motor cables; has been sent I'm told.
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attached a small script to test Outputs.
copy it into C:\Mach3\macros\ y o u r Profilename
useage MDI/code:
M777 P1 Q1 -> Switches Output 1 ON
M777 P1 Q0 -> Switches Output 1 OFF
M777 P2 Q1 -> Switches Output 2 ON
M777 P2 Q0 -> Switches Output 2 OFF
.
.
.
.
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Thanks TPS, copied it to the CNC profile in macros and entered the script. Output 1 responded by flashing the LED in 'Diagnostics' with the P1Q1 code. P2Q1 had no visible effect anywhere in 'Diagnostics'.
Would I be correct to think that the Q1 and Q0 of the code designates the On or Off state of the output; so would I be right to think that P3 would designate the 3rd Output? Or do they designate the BOB P2 to P7 Outputs?
Lots of Questions: What really, are the 'Outputs'; the motor Outputs, the BOB Outputs P2 to P7?
What is actually tested; the Mach3 software's ability to conduct this particular diagnostic process or does this diagnostic actually test all outputs?
Should I leave all outputs in an 'On' state? i.e. P1Q1, P2Q1 etc?
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it is only switching Mach3 Outputs, witch are assigned in Config -> Port's&Pin's -> Output Signals.
i would Switch them all off after testing.
Yes P Parameter is for Output Number
and Q Parameter for state of the Output.
if also will only Switch Outputs witch are enabled in Config -> Port's&Pin's -> Output Signals.
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That's good, so in my case it's 'Output Signals' - Output#1 - enabled is ticked - Port#1 - Pin number 17 - Active low is crossed; one output only ....Output#1.
Question - do the pins 1 to 17 that are printed on the BOB correlate with the parallel port pins? Also, the BOB Pin17 seems not to be connected to anything, so what is Output#1 used for?
I received the cable this pm, made the harness and attached it to the motors. I'll connect it to the TB6600s tomorrow, turn it on and hope smoke is a past experience.
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according to the documentation ZASto has posted in Reply #77
pin17 can be used for b-axis direction (witch you don't Need) or for
the relay, witch you may Need in future for spindle on.
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The pin numbers in the documentation do correspond to the physical pin numbers of the parallel port.
The 5 input pins 10, 11, 12, 13 and 15 have the identical circuitry. The assignment of functions, X LS, Y LS, etc is the conventional standard used in the CNC world. You could chose to rearrange them as long as to change the MACH3 screens to match.
The 12 output pins are a bit different. While they all are buffered and appear on the terminal strip, several have additional circuitry.
Pin 1 also connects to the PWM to analog converter used for spindle speed.
Pin 14 has 3 buffers so it can drive multiple stepper enables.
Pin 17 can be jumpered to the relay usually used for spindle enable.
Pins 1, 8, 9, 16 and 17 are not used by your application and could be used for additional functions. For example, Pin 17 and its relay could be used to operate the chip vacuum as the coolant function of MACH3.
Start up and test the steppers one by one. The Y axis appears to be the heaviest and will determine the max speed of the system.
https://www.machsupport.com/forum/index.php?action=dlattach;topic=43939.0;attach=54790;image
Remember the 1.5A current setting is a guess, check for overheating as you tune the motor. Changing from 1.5A to 1.0A will halve the heat. (Watts = current squared times resistance)Since you will be operating in a hot environment you could begin at 1.0A and see if it gives satisfactory performance.
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Thanks for the info
I set the TB6600 current switches to 1 Amp and connected cables to motors one by one, and tested for function and effect before connecting the next one.
All motors jog; the motors and gantry are quite noisy. I'll clean and grease the rails and Z Axis gantry v joints to quieten them but I think most noise comes from the X and Y motors.
X motor - direction is reversed, the motor emits a fairly loud beacon type signal when stationary and is warm.
Y motor - direction is reversed, it emits the same signal but not as loud and is also warm.
Z motor - direction is correct, it emits a soft very high frequency signal and is as cool as a cucumber.
The system requires fine tuning; where to from here?
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Turned the system on again after the last post and the Z axis is also reversed. I must have dropped my attention the last time or can the software reverse the Z direction to normalise Z motion with that of the X and Y axes? ???
The motor noises have reduced somewhat but the same frequencies are still there.
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I haven't see a picture of the TB6600 switches so I don't know how clearly they are marked. That's why I suggested measuring the voltage with the microstepping set to 1 to verify they are set correctly. If you are sure of the settings change the microstepping to 4 will make the operation smoother. That will change the mm/step also.
I don't know why the direction changed. Perhaps changes you made earlier don't take effect until you rebooted the program.
Changing the tick in the Dir Low Active column on the Motor Outputs page will change the direction of the axes.
The stepper driver controls the current by chopping the voltage to the motor like PWM. That could be the source of a high pitched noise.
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The switches are well marked and the states, and their switch positions, very visibly printed on the TB6600 casing. I'll change microstepping to 4.
I'll 'untick' and therefore 'cross' the 'Dir Low Active' boxes of all 3 axes to reverse their direction.
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The Y axis reversed its motion this time.
I now have the X and Z 'Dir Low Active' crossed and the Y 'Dir Low Active' ticked to run the axes in the right direction.
TPS, could this be a Mach3 software issue? It's not a wiring issue; might the TB6600s make the change?
The X and Z motors have quietened on the microstep 4 setting whilst stationary. The Y motor is noisy. I'll see what the situation is if I revert back to the last microstep setting.
It's getting dark, so Ill adjust mm/step and acceleration, and test microsteps tomorrow.
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"normaly" the Software will not Change stettings. "maybe" you missed the Apply button?
if you Change microstepping to 4, just multiply your step's per by 4.
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The motor may sound louder if something in the drive chain is loose. See if pulling on the carriage reduces the noise.
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Yes, that is a possibility, TPS, but I'm quite pedantic with my processes and check, and double check, each step to be taken. I'll go through all the wiring again to make sure it's correctly soldered and connected to all the components. Thanks for the microstepping info, I've entered the new figures and motor smoothness has definitely improved.
I'll check the gantry drive train for looseness to reduce noise further, MN300. Just one question: could the anomaly in 'Motor Outputs' (having the Y Dir Low Active ticked but the X and Z crossed) cause problems at a later stage when I'm running code?
With Christmas almost upon us, I'll wish you all and your families a fulfilling and enjoyable time and a great new year.
I'm going to sign off now for a month or so to prepare for and share time with family, and to play with and go through the CNC work done so far with a fine tooth comb.
Thanks for your help TPS and ZASto, and for all the work you have done MN300; I could not and would not have done it without you.
Connect again in the new year. :)
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The direction which a given rotation of the motor moves an axis depends mechanical setup of the machine. The tick in the Motor Outputs page tell MACH3 what that is.
Happy Holidays to you too.
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Played with the system before the NY.
The Y channel switches the motor direction at random when the same Mach3 jogging hot key or the 'Fly Out' jog button is pressed. The Mach3 DRO keeps counting in the same direction despite the direction of the motor. i.e. press the forward jog, motor rotates in Positive (+) direction and DRO values advance Positively (+); press the same key again and motor may, at random, rotate in Negative (-) direction but DRO will still advance Positively (+).
I have swapped the TB6600s and the motors but the same happens to the Y channel. All wiring connections have been checked many times and are correct.
When interchanged, all drivers and motors work fine on the X and Z channels.
It's either the BOB, computer or Mach3.
What can I do to identify the cause?
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If I read your description correctly it says the DRO counts in the direction you command but the Y motor moves in a random direction. This could be a fault on the BOB board.
Try swapping the A axis pins with the Y axis. Change the MACH3 configuration page and move the wires from P2 and P3 to P8 and P9.
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Made the changes as you suggested but as applied to the Y axis. Moved wires from P4 and P5 to P8 and 9, and reconfigured the pins in 'Motor Outputs for the Y and A axes. The Y channel still changes the Y motor direction at random.
Changed the Y Pul (P4) and Dir (P5) connections to the X and Z channels and random direction change of the Y Motor continues.
It would have to be a Mach3 setting or the computer , wouldn't it?
I checked all the soldered joints again ... all OK.
I also checked the Mach3 settings as per the BOB installation guide ... but the Device Manager/Mach X Pulsing Engines/Mach3 Driver computer icon has a Blue question mark. The ECG Savebase BOB User Manual states that the ? should not be there. Could this be the issue and how do I remove it?
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Changed the Y Pul (P4) and Dir (P5) connections to the X and Z channels and random direction change of the Y Motor continues.
I 'm not sure I understand what you meant here.
Did you try assigning X or Z axes to pins P4 and P5 to show that hardware works?
It does sounds like you have eliminated the BOB as the source of the problem.
If you don't get help from a experience MACH3 user here you might want to start a new topic.
If there is no other alternative you could uninstall MACH3 and start again.
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That's correct, I assigned the other axes P2, P3 and P6, P7 connections and Mach3 Motor Output pins to the Y motor but the problem persists, so yes, it would have to be the Mach3 setup or the computer itself.
Before I start a new topic re BOB and driver setup in Mach3, I'll reinstall Mach3 to see if the Mach3 Driver installs without a question mark.