Messages

161

General Mach Discussion / Re: Settings or machine problem

« on: December 05, 2006, 06:19:29 AM »

Hi,  Hood is right. Although a power supply of 75v would be better, It seems by your explanation in the email this will not sort your problem immediately. You said that when the axis miss steps the steppers moan.

Are you saying that when the problem occurs, all the axises stop at the same time (for how long) and then start working again normally? This is the big question because if that is so we can eliminate some of the things it might be.

Your port and baud settings are OK. As are the current resistors. The mounting of the Gecko units should be OK for steppers under 3amps although heat transfer paste between the Gecko unit and the mounting would be better in the long term if you are using the machine all day every day. But don't worry about this for now.

Shielded cable has the earth/ground wire on the outside of all the other wires made like a lattice (similar to TV aerial cable or audio cable)
It acts like a Faraday cage and keeps stray signals from getting in or out of the cable long it's length. All of your signal wires should be shielded ( wires to the computer and the step and direction on the gecko's)

I hope I've answered most of you questions but to get back to the problem I need a better explanation of this moan from the steppers or perhaps a video of this problem happening.

Does the moan sound like a low vigorous hum?

Regards
John

162

General Mach Discussion / Re: Settings or machine problem

« on: December 04, 2006, 04:35:16 PM »

Hi,  I've been wracking my brains on your problem, and discounting any problem with your computor port voltages if the missing steps happen on all of your axis and not just one the problem may lie with using a single power supply with all axises/axis (plural). As you have capacitors rated at 35v your power supply must be lower than this.

Also does the power-supply  supply enough current when all drives are running at max stepping speed?

The way to sus this will be to measure the supply voltage when all drives are active but not stepping, then run a program that uses all the drives and ramp up the stepping speed. If the voltage drops then youv'e maxed out the current capability of the supply.

To get really good stepping rates with stepper motors, a supply of 75 volts is required.

John

163

General Mach Discussion / Re: Help! Please! this Chaos has to stop!

« on: December 04, 2006, 12:04:23 PM »

Hi, I noticed in the above pic you are using Gecko drivers, Are the drivers mounted on heatsinks with heat transfer paste.
The drivers should not be very hot if your steppers are not. There is something wrong there. Find out what amps per phase the steppers are and check the limit resistors for the geckos.

Regards

164

LazyCam (Beta) / Re: Pimp my Lcam

« on: November 27, 2006, 03:06:31 PM »

I'm with Graham, I'm sure there are a lot of lathe machinists out there using Mach and would like the benfit of Lcam.

I still code all by hand and use of the lathe wizards is very helpful but I still find that the finished billet never looks as it should in the tool path window even though the code is correct which makes it difficult to make small changes to the code and see it visually before committing to a test cut.

One thing could make a big difference, being able to fix the billet diameter for the display.

Here's hoping that Lcam for the lathe will eventually become a reality. 


Regards to all.

165

Macros / Re: Using the serial port for a toolchanger macro

« on: November 17, 2006, 03:05:11 PM »

Hi Dave, I haven't made the PCB yet for it, I've been so busy with work. The code for the micro is done and part of the PCB design. I've left the electrics in the toolchanger alone as the PCB replaces the existing one in the box and has alot of other ins/outs on it.

I've used opto-isolators between the micro port pins used, so the 3 opto-sensor wires from the toolchanger sort protection and the voltage drop. The motor control is supplied by an L298 bridge with a current sensing op-amp back to the micro so when the motor reverses onto the stop, the current will increase to a cutoff point and tells the micro to cut power.

The reason to do it this way comes from first getting a faster motor with gearbox to replace the old lot. I had a good Maxon motor/gearbox from an ebay sale a while ago and tried it direct on the worm drive.

It was turning the tool carousel at least twice as fast. Great! I'll make a new mounting plate and drive dog to the worm. I then measured the stalling current to find it was well over 3 amps so some kind of current limiter was needed.

I see what you mean with the 'job done' single code, I didn't see that before and it makes sense now you've mentioned it. Many thanks again, a slight mod to the micro code and the macro then.

Regards
John

166

General Mach Discussion / Re: Driver watchdog triggered

« on: November 16, 2006, 03:16:35 PM »

Hi, I see what you mean. Your computor speed seems fine. I have never had the error whilst the machine is working only when the screen was updating the new file I loaded.


Cheers

167

General Mach Discussion / Re: Driver watchdog triggered

« on: November 16, 2006, 01:03:54 PM »

Hi, I have found that this happens on computors that are under 1ghz. I guess windows is trying to update the screen and taking control away from Mach3 which Mach3 dosn't like too much.

I upgraded my processor from 733mhz to 1.3ghz and the problem disappeared.

Cheers

168

General Mach Discussion / Re: DC Spindle drive question, What to do with it!

« on: November 05, 2006, 04:55:06 PM »

Hi Graham, If your controller has a 0-10v for speed regulation you can connect one of those converters to run your controller from Mach3.

From the circuit you posted it looks like there is a 0-10v connection, measure the voltage on the 2 wires (high voltage precautions taken) and adjust the spindle speed, if the voltage changes from 0 to 10v then this is ideal.

The first converter uses step and direction signals from Mach and the second one can use a verity of ways.

The second converter can use PWM from Mach and this is ideal for using G96 on a lathe.

Have a read of there literature on the converters.

cheers
John

169

General Mach Discussion / Re: DC Spindle drive question, What to do with it!

« on: November 05, 2006, 03:48:43 PM »

Hi, What you need is something like this at http://cnc4pc.com/Variable_Speed_Control_Board.htm or http://www.homanndesigns.com/DigiSpeedXL.html



Regards
John

170

General Mach Discussion / Re: Serial port inputs and outputs

« on: November 05, 2006, 03:29:09 PM »

Hi, You might be interested in a macro I have posted in the downloads section of the forum which uses the serial port to communicate with a microcontroller to operate a toolchanger.



Cheers