Hi everybody,
I am new here. Hope I can ask something to the community.
I have an Optimum BF20 installed stepper-motors on four axis, designed power-electronics and everything is working pretty fine with linuxcnc.
Now I want to connect the spindle as well. I am able to read in the spindle-speed by using the signal used by the rpm-meter on the machine (there is an initiator collecting four signals per revolution). I am also able to set the spindle-direction by switching some relays. Is there an easy way how to set the spindle speed? I found a lot of information how to set up PID, I think this is the easier part. My problem is, that the potentiometer connected to the motor controller for controlling the speed is floating at roughly 150V AC - hurts a lot .
I found some information that I need a 0-10V signal to set - ok I can do this from a pwm-signal and a low-pass filter. But how do I connect this to my floating 150V AC?? I made some trials with an optocoupler, but this is a big sh**, it's not linearly enough
I'm afraid of destroying the controlling when forcing it to ground
Does someone have some experience with this?
Thanks a lot Schorsch