Emco Compact 5 PC auto tool changer

ArcEye wrote: OK, we have been a cross purposes.

Until now, you have not actually said that you have an ATC complete with original motor AND a Nema 17 stepper.

I could not work out why you were taking so much interest in a board to operate a motor you didn't have.

Yeah, I should have been more clear at the start.

About 80% of the info I pasted in regarding the board went completely over my head. I included mostly because I thought it might turn out to be of interest to others.

ArcEye wrote: So long as you have details of what the inputs and outputs do, it will be possible to control it with linuxcnc.
I am surprised there are no sensors and it would no be beyond the wit of man to add at least one, to mark Tool 1 position at least.

But worst case scenario would be that the operator tells the component what the current tool is at startup and it can work out the rest from there.

I think I have the details. Just don't know how to use them yet and have no present urgency. I was just hoping someone would reply and say it's already been done.

FWIW, I found examples of EC5 ATCs that had sensors added, but I think all of them also had a stepper.

I'll come back to this and report any progress after I get further with the basics.

Thanks for the replies.

My concern for using a stepper would be consistency and holding force. The DC gear motor uses full reverse power to stall the changer against the pawl. A nema 17 motor most likely will not have the same holding torque, since it is not geared down. On top of that, the stepper will only have maximum holding torque at its fixed step position. If you try to stall the stepper against the pawl, most likely it will not be ideally aligned with that fixed step position, so it will be in a weakened torque position--and might even bounce back a full step. OTOH, maybe the worm gear makes it moot, as long as you can align it adequately.

ArcEye wrote: But worst case scenario would be that the operator tells the component what the current tool is at startup and it can work out the rest from there.

It looks like it would be easy to also add a proximity sensor to detect the pawl position, which would be much better than a simple time-delay.

The most likely scenario for pawl-breakage is the cutting tool hitting the chuck, or some other overload scenario. I would consider it a useful mechanical fuse and resist strengthening it.

it occurs to me that all toolchanger sequences are made up of a set of standard behaviours in various orders. The typical toolchanger is a state machine running a hard-coded sequence.
I wonder how hard it would be to define the set of all states, and allow someone to "loadrt toolchanger sequence=acbabdf"

krlynn. is it possible to make a high resolution Picture from the Toolchanger Board front and back.
I have a C5CNC with the newest Software and want a toolchanger for it. For that purpose I bought a small dividinghead
which I want drive with a DC motor and a self build adapter board.
But, if you have all, what you need, why don't you use it. The toolchanging of the C5 has nothing to do with the toolsparametres. The user must give as much toolchange pulses, like the changer should switch. Thats always a short time the motor runs with full power until its over the stopper. Until that the motor runs continuously with very reduced power against the stopper.

this is exactly the same as the orac
although i dont see any positional opto's by the picture , although thats hidden at the other end
and the bottom plate , if their fitted

the holding torq is the fact that it reverses against the stop pawl , so the force is not taken by the motor
the only down side is the toolchanger can only rotate one way through positions
controlling the motor is easy with a few relays for run and forward /rev and to run a full wave rectifier in forward and a half bridge in reverse , crude but it works

Any news on this thread? Did you get it working?

Seems like an h-bridge with one direction pwm'd down a bit would be ideal. Depends on the current of the motor of course.

Just starting a project to CNC a Compact 5 myself using the original components. I want to get a tool changer working too.