PM25MV CNC Mach 3 Spindle control question

[yz400fer69]

I was curious if anyone has converted a PM25 CNC using mach 3 for spindle control. I am curious if there is a wire diagram, or pictures, video or explanation anywhere as to how it should be wired.

Unfortunately there is no jumper pins on the board like the G0704, so I will have to cut the pot wires and use those.

Thanks
Dave

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[yz400fer69]

Anyone?

[CS900]

It should be fairly easy to map out the current wires with a multimeter. I haven't cracked mine open to look, but I assume its a standard 3 wire pot inside. I say chop the sucker. worst that happens is you have to splice them back together.

[yz400fer69]

It should be fairly easy to map out the current wires with a multimeter. I haven't cracked mine open to look, but I assume its a standard 3 wire pot inside. I say chop the sucker. worst that happens is you have to splice them back together.

Opened things up last night and turned motor on, tested the pot output at full speed (5v). Spliced into the 3 wires that are going to the pot, got my BOB configured and I am having an issue. The spindle turns on/off, and my 0-10v port is tuned for 5.0v at 2500 RPM. I have set up my spindle pullies but when I change the RPM in mach, the motor rpm does not change (although the voltage output does).

Messed with it for a bit, and then wired the POT back in but the pot does not control the speed either - it is all (full speed) or nothing (motor doesn't spin at all). When the pot is below full, the motor turns off completely.

Any ideas?

[CS900]

how are you controlling the 0-10V signal with mach3? spindle break out board?

[yz400fer69]

I have a C11GS breakout board. I have my isolated 12V supply going into the inputs of the breakout board, the ground from the POT wired to the ground of the 12V power supply, and my "wiper" wire going to the 0-10V output of the C11GS BOB.

[yz400fer69]

Spent some more time on it last night and I have it working well now. Speed up, speed down, m03 and m04 commands work as expected.

[CS900]

awesome. what was the problem?

[Skippyman]

yz400fer69,

That's great that you got it working. Any chance you can post a wiring diagram? I'd like to do the same with my PM25.

Skip

[nar]

I have a new PM25mv and was gearing up to control the spindle speed from my BOB. Didn't seem to work, so got in there with a voltmeter to try to understand what's up.

I don't know if I believe the readings, but it seems that the pot is adjusting an AC voltage from the controller board. That could explain the very odd results I'm getting.

There's no way my (or any) BOB will put out AC voltage to control a spindle motor.

Anyone out there getting similar readings? In the meanwhile I've implemented a simple relay control (in the F-OFF-R circuit). Pretty easy, at least I get spindle on/off. I can dial in the speed by hand.

Sure do wish they'd publish a schematic...

Neil

[yz400fer69]

Hi Neil,

I was able to get my machine 100% controllable with Mach3 and a C11GS BOB. I purchased a separate / dedicated 12V power supply to control the 0-10 (spindle speed).
I used 2 of the 3 relays to control the M3/m4.

Send me a few pictures of what you have to dburt520@gmail.com and let see if we can figure it out.

Thanks
Dave

I have a new PM25mv and was gearing up to control the spindle speed from my BOB. Didn't seem to work, so got in there with a voltmeter to try to understand what's up.

I don't know if I believe the readings, but it seems that the pot is adjusting an AC voltage from the controller board. That could explain the very odd results I'm getting.

There's no way my (or any) BOB will put out AC voltage to control a spindle motor.

Anyone out there getting similar readings? In the meanwhile I've implemented a simple relay control (in the F-OFF-R circuit). Pretty easy, at least I get spindle on/off. I can dial in the speed by hand.

Sure do wish they'd publish a schematic...

Neil

[nar]

Hi Dave and thanks for the reply. The BOB I have does indeed have a separate 12v supply, and provides a 0-10v dc output controlled by spindle speed S commands. I have confirmed that this aspect does indeed work.

Here is a small excerpt from the "schematic" that PM provides:


I experimentally determined which side of the Speed pot was the negative terminal (ground, or so I thought), cut the line to the wiper (middle terminal) and then connected my 0-10v BOB output between the ground lead and the newly isolated line that previously went to the wiper. I expected the motor speed to follow the DC voltage coming from the BOB. It didn't.

I then re-connected the original pot and measured the voltage between the wiper and the ground terminal and got some VERY strange readings. In DC-reading mode my meter was distinctly not happy, the readings jumped around like crazy. I then switched to reading AC voltage, and then the readings were stable if a bit puzzling, ranging from about 5vAC to 8vAC as I turned the knob.

I'm not yet convinced that my connections were good, I will go back and repeat the above with fresh wiring. In the meanwhile, I'd really like to know what worked for you. Also, what is the vintage of your PM25, perhaps we have different controllers?

Even if I could make this work, I'm leery of controlling speed with a BOB that does not support Charge Pump safety (are you using this feature?).

Neil

[Djabi]

Has anyone figure out how to control the spindle direction and speed? I'm planning to work on this next couple of days and I'll appriciate any pointers.