That sounds like a perfect match to doing THC. Thank you, that will be what I try for my CNC plasma project.

Back on the questioning the viability for the Duet as a controller for an EDM machine. Would it be possible to have this control loop apply to more then just Z axis position but have it control movement along a path. Think if it have a analog voltage as the feedback this controls how fast the machine moves along a path. If it overshots it may need to backup. The output of the EDM power supply is an analog voltage related to the arc condition and a serial port to configuration and status information.

Interesting, so that is something that could be take a voltage as an input to one of the extra ADC pins to the control loop? If so this would eliminate the need for to buy a 3rd party THC (Torch Height Control). I would just have to have some level conversion from the plasma cutter to what the Duet could handle.

So how is a probing cycle handled? I mean it moves a direction till the controller receives some indication and backs up. Would this not work on a arbiary movement command? I know this works off of a binary input and would not be ideal for the EDM case but it may work.

@OwenD said in Negative Feed Rate:

FLCNC F2100

If it does not work out for CNC Plasma project I will likely use LinuxCNC as I have some experience with it. I really like the web interface part of the Duet because I can put some simple CAD, nesting, and CAM in the Duet web interface. I have been playing around doing this and so far has some good luck in my first couple of hours of work.

The question I had was about negative feed rates was for an EDM. I was curious if it could support that.

@NitroFreak exactly, good call. I think this would be useful for a CNC plasma that I am working on if I get a torch beak indocation.

@dc42 Wow thanks for the fast response.

Is there a way feed along a path until something is triggered to the controller and have it back up a distance? This backup distance is something that I would like to set as a parameter I could change.

Thanks,
Wylie

Hello,

Is it possible to have a value negative feed rate with the current firmware? Meaning I can play the motion path in reverse without change to the GCode.

Thanks,
Wylie