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Messages - chrisjh

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111
LazyTurn / Re: LazyTurn
« on: July 11, 2009, 06:44:02 AM »
Hi Guys,

I am keen to help with this development.  I am not an expert but have read the well documented manual and tried to follow the instructions as best I could.  I created a model in Solidworks and from that model created a dxf upper profile and saved it in ACAD 11/12 format.  See attached dxf.

Whenever I load the saved dxf into Lazyturn I get a greatly oversized profile.  Lazyturn allows me to change the stock diameter to any value I wish but will not allow me to change the profile diameter to anything less than the default value that Lazyturn gives it.  See screenshots below.

Regards

Chrisjh

112
General Mach Discussion / Re: Mach3 Spindle Speed Problem
« on: October 29, 2008, 08:35:01 PM »
I have done some more experimentation and Mach3 definitely has a bug in the Spindle Speed Control.  The problem has nothing to with whether you use open or closed loop.  I have tried 2 different computers using both Mach3 and Quantum with exactly the same repeatable results on my mill and my mockup of my lathe in progress.  In both cases I am using PWM to control the spindle motors.  The Mill uses a PWM to Analogue Converter Board and Motor Control Board to control the 1000W DC Brushless Motor.  The lathe uses my own PWM to Analogue Converter to control a Danfoss Microdrive VFD to a conventional 3 phase AC Motor.

I am also using a Smooth Stepper (what a great leap forward in technology, I love it).

If you are using PWM, try this to see the problem:

Command Mach3 to go to any speed (say 750RPM) via the Spindle Speed Dialogue Box or MDI

When the spindle is running, press the "Reset" Button.  You will notice a destinct drop in RPM.

You get the same results if you:

Command Mach3 to go to any speed (say 750RPM) via the Spindle Speed Dialogue Box or MDI

When the spindle is running, press the override "up" arrow twice.  You will notice a destinct drop in RPM on the first press of the arrow and then the spindle will respond normally on the second and subsequent presses.

I have monitored the PWM steam out of Mach3 with my CRO and the PWM mark to space ratio (duty cycle) changes accordingly so the problem is definitely with Mach3.

Any hints as to how to correct or overcome this would be greatly appreciated.

Regards

Chrisjh


113
General Mach Discussion / Re: Mach3 Spindle Speed Problem
« on: October 28, 2008, 10:01:27 PM »
Hi Ray,

I am currently testing all of my electronics on the bench open loop.  Thanks for the pointer in the right direction.  That would explain why the RPM box always displays "0".  I often wondered about it but now makes sense.  My intention is to run closed loop with a spindle pulse from a slotted disc or Hall effect sensor.  I will trial a fully fedback system ASAP.

Thanks and Kind Regards

Chris

114
General Mach Discussion / Mach3 Spindle Speed Problem
« on: October 28, 2008, 08:12:21 PM »
I am using Mach3 V3.041 with a Smooth Stepper in PWM mode.  Base Frequency is 1000 (but the problem persists whatever Base Frequency I use).
The problem is very consistent and it doesn’t matter what method of requesting any Spindle Speed.  (MDI using M and S commands or from any Spindle Toggle Buttons on any Mach3 Tab).

The problem with the spindle speed is as follows:

Select a speed (say 1000rpm). Spindle Override reads 1000 same as Spindle Speed and SRO reads “00”.

Toggle the spindle on.  The actual speed of the spindle always starts at a slightly higher speed than that requested. 

Pressing “Reset” under the Spindle Speed Tab always brings the speed back to correct requested speed and subsequent requests for speed changes (via Spindle Override or actual commands for a different speed) from there on are correct and consistent.

It appears that Mach3 is in some form of Spindle Override (approx +10%) when first started.  I first noticed this problem a couple of years ago but ignored it and learned to live with it with my mill.  However I and building a cnc lathe with a VFD controlled Spindle Motor and want better control over spindle speed.

Also there is another dialogue Tab under the Spindle Speed Tab labeled RPM.  It always reads “0” regardless of what I do with Spindle Speed and it does not accept any characters typed into it even though it changes background when selected. So I ignore it.  What is the purpose of this “RPM” Box and should it indicate something?


Regards

Chrisjh

115
General Mach Discussion / Re: VFD Forward/Reverse Relay Control in Mach3
« on: October 17, 2008, 08:39:43 AM »
Ray,

I tried your suggested settings and got some improved control over the Analogue DC O/P of the C23 BOB.

However with extensive trial and error, I concluded that the LM2907 frequency to voltage converter was a poor design choice.  I found that it was too sensitive to pulse width variations, Mach3 configuration variations and did not give a full range of 1 - 10VDC O/P.  Also the voltages that I did get out of it were far from linear and I never saw the same voltage out twice for the same requested RPMs.  I am trying to be diplomatic here.

I quickly realized that I was wasting time trying to get the smooth, linear control that I wanted to control a VFD, so I decided to abandon the LM2907 for a PWM approach.  I threw together a prototype PWM to Voltage converter Board designed by Paul Kelly. See http://www.cncathome.com/vfd.html  for his schematic.  Thanks Paul.

I reconfigured Mach3 for PWM Spindle control and set the PWM O/P to Port 2 Pin14 driving Paul’s design.  I trialed both 1000Hz and 2000Hz Base frequencies and concluded that either setting would be OK for my proposed lathe conversion.
My slightly modified schematic and test results  can be found at http://www.cjh.com.au/PWMConverter.pdf

Tests clearly show a linear progression from 50 RPM to 1400RPM (the range that my intended motor will run over).  Extensive testing over time ( a couple of days) revealed very consistent voltages out for any requested RPM using Mach3 as the PWM signal source.

I am now confident that this VFD control approach will work and next week will proceed with the procurement of the Danfoss VFD and Australian manufactured 3 Phase motor 0.75KW for the next stage of development.

I’ll let you know how that goes in a couple of weeks.

Regards
Chrisjh

116
General Mach Discussion / Re: VFD Forward/Reverse Relay Control in Mach3
« on: October 12, 2008, 06:55:28 PM »
Hi Ray,

Thanks for your notes on your experience .  I will need time to digest your notes and perform some experiments.

Last night I was able to successfully cofigure the 2 mechanical relays for forward and reverse (M3 operated one of the relays and M4 operated the other).

I then tried following the C23 BOB procedure for step to analogue via Pin 14 Port 1 without success.  No mater what I did the analogue O/P remained at about 9VDC.  It was getting late so I gave up with the intention of getting to trace the Step Pulses through the BOB using my CRO later today.

I'll let you know how I go.

Regards

Chrisjh

117
General Mach Discussion / Re: VFD Forward/Reverse Relay Control in Mach3
« on: October 12, 2008, 06:30:57 AM »
Ray and Jim,

Thanks for the pointers.  I was focussed on PWM because my cnc mill works with PWM.  Now that have been pointed in the right direction, I have realized that the C23 BOB indeed works on step pulses and not PWM. I am now concentrating on working out a plan for steps to be converted to 0 - 10VDC for speed control. 

I now plan to use my original idea to use the 2 on board mechanical relays for channelling the 24VDC from the VFD back to the Forward (Start) and Reverse pins of the VFD but now will use the step function through the C23 BOB to control the speed.

One thing I learned is that the Smooth Stepper firmware is smart enough to recognize errors on my part in the ports and pins configuration.  For example, it reported that I had mistakenly assigned pin 14 on Port 1 twice.  When I set up the step function for the analogue conversion on Pin 14, it complained that I had not assigned a corresponding pin for direction.  I could not see that direction was needed (the spindle direction having been taken care of by the forward and reverse relays).  However to keep the Smooth Stepper happy, I assigned an unused pin to direction.  Smooth Stepper now appears to be happy.

I will report further progress in the near future.

Kind Regards

Chrisjh

118
General Mach Discussion / VFD Forward/Reverse Relay Control in Mach3
« on: October 11, 2008, 02:26:06 AM »
I am planning a CNC Lathe conversion based on the following Electronic Components:
1.    Smooth Stepper
2.   CNC4PC C23 Breakout Board
3.   Danfoss VLT Micro Drive FC51 VFD http://www.automationdirect.com.au/Welcome/drives/Danfoss.html
4.    Mach3

All was going well until I was planning the Forward/Reverse function for the VFD.  The Danfoss VFD has "Start" and "Reverse" Input Pins which can be selected via external relay contacts.  The VFD supplies 24VDC out for the purpose of being switched to various Input Pins including "Start" and "Reverse".
I am interpreting the "Start" as being "Forward" and “Reverse” as being "Reverse".
I plan to use the PWM function within Mach3 in conjunction with the CNC4PC C23 Breakout Board to generate the 0 - 10VDC speed control for the VFD and to utilize the 2 mechanical relays to select Forward and Reverse.  According to the Silkscreen on the C23 Breakout Board, the 2 relays are associated with Pins 1 and 16 (presumably of the Port 1 Ribbon Cable Connector).

I configured the Ports and Pins within Mach3 to do this by:
1.   In the Spindle Setup Tab, enabling M3 and 4 to O/P 1, Use Motor Control Output Checked, PWM Control Checked, Disable Relays Unchecked, and PWMBase Freq to 1000.
2.   In the Motor Outputs Tab, enabling Spindle, Port 1 Step Pin 14, with no direction Pin selected.
3.   In the Output Signals Tab, enabling Output 1, and Selecting Port 1 Pin 14.

The problem I have is that I don’t understand how to associate M3 with Pin 1 (thus energizing one relay for “Forward”) and M4 with Pin 16 (thus energizing the second relay for “Reverse”).
Can anyone suggest a way to do this or am I barking up the wrong tree?


Regards

Chrisjh

119
Share Your GCode / Soft Start for Spindle Motor G Code Routine
« on: September 09, 2008, 08:34:07 PM »
Hi,

I have a Syil SX3 Mill fitted with the original Seig Spindle Control Boards.

Later boards have a "soft start" feature for the spindle speed. I personally don't like the later boards because of the slow accelation rate to spindle speed. The soft start feature appears to emulate pushing of the front panel up arrow buttons and is set in firmware. It is far too slow for the spindle to come up to full speed of say, 3000rpm.

The original boards do not have a soft start feature and this places a lot of stress on the spindle motor and belt when a speed of 3000+rpm is selected under G Code Control.

When is issue S3000 from 0 RPM, my machine instantly overshoots the requested set speed and settles back to 300RPM.

I have a soft start G Code solution which meets my requirements which I tested this arvo as follows:

(Soft Spindle Start Template)
(This routine brings the spindle up to 3000 rpm in small steps)

(CJH 27Jun08)

G00 G17 G21 G40 G49 G50 G64 G80 G90 G94
M6 T6 (5mm Drill)
M3 S750
G04 P100
S1000
G04 P100
S1500
G04 P100
S2000
G04 P100
S2500
G04 P100
S2800
G04 P100
S3000
M8 (Coolant on)
F2000
G00 Z10
G00 X0 Y0 Z3

G00 Z15 F2000

M5 M9 (Spindle and Coolant Off)

G00 X0 Y0 (Return to start position)
M30
%

The "G04 Dwell in ms" config settings under "General Config" in Mach 3 or Quantum must be selected for this code to work. I am using Quantum at the moment.

What the code does is to start the spindle at 750rpm, then waits (dwells)for 100ms (0.1 seconds), then increases to 1000rpm, then waits for another 100ms, and repeats this in 500rpm increments until 3000rpm is acheived. The speed ramp up to 3000rpm happens very quickly and smoothly without the stress on the motor and belt.

You can experiment with G04 P********* dwell times and the speed start speed and increase increments to suit your machine.

Hope is is useful to others.

Regards

Chrisjh

120
Hi All Syil X3 Mill Users,

Syil X3 Mills are Seig X3 Mills converted to cnc.

At the attachment below you will find the procedure that I used to calibrate the spindle speed of my Syil converted X3 Mill. The procedure calibrates the speed requested by Mach3 to the actual speed of the machine.

I was always annoyed that I could never attain the maximum 3400 rpm under Mach3 control. The low end wasn't too bad as delivered but the top end was miles out.

I have now adjusted my machine following this procedure and I am now happy. Of course the calibration is for speed settings with no overrides.

Hope this helps for those who like myself wondered how to do this for 12 months.

I was lucky that my machine front panel speed display was quite accurate when checked with my laser optical tacho so I did not need to adjust this. If any one knows how to calibrate the front panel rpm readout, please let me know and I will amend the procedure below so others can benefit.

Kind Regards

Chrisjh


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