7i77 ground vs. servo amp ground

Nope, Linuxcnc is ok. I'm also happy so far with the way the 7i77 works... it seems a lot easier to understand configuration wise than the 7i37 is.

I am running the limit switches directly to the drives, so I have a second level of safety in case something were to go catastrophically wrong with the control PC. Once I have the soft limits set in Linuxcnc I should never hit the hard limits, but it'll be nice to have them there.

I was having some issues with the way the drives define "active" on their input pins, but I have it worked out now. I think I even found a configuration that will work without relays - active high with the limit switch pins wired NC to ground. The shutdown pin has an internal pullup resistor that was confusing me before.

Erik

Just to finish off with what I did, I got everything working once I got the grounds all solidly connected.

The limit switches are connected as NC unidirectional, IE I can reverse away from a limit switch if needed. I managed to find a config that worked for this without relays - basically I had to switch from the default limit handling for the BA20 and use active high, then use the limit switch loop to tie the inputs to field ground. Because the ba20's inputs have an internal pull up, this is the only way to use NC limit switches.

I've just about got the encoder settings tuned and I'm connecting other peripheral devices like the sensor for oil level in the way lube pump and the limit switch that senses back gearing engaged.

Next up is connection of the air valves for the power draw bar and the WJ200 VFD that controls the spindle... I'm going to go with RS485 control, possibly with the new driver in pre 2.6 for that.

Then onward to the mpg, probe, and other fun.