can't find stepgen signal

I can't figure out how to generate a stepgen signal from the 7i85s for the Z axis. I'm sure this is a novice mistake I'm making, but I'm just not sure what else to try.

I have a 7i92 7i77 for the XY servos 7i85s for the Z stepper. The 7i77 is connected to the 7i92 by RS232 cable and the 7i85s is connected to the 7i77 by RS422 CAT5 cable. I am running the 7i92_7i77_7i85sd.bit firmware. All cards appear to have power and their pins show up in the HAL Configuration tool in LinuxCNC. Based on the attached hmid_output, I'm expecting the STEP signal to come from 7i85s pin TB2-11 and the DIR from TB2-13.

When I try to move the Z-axis while measuring voltage on these pins, I don't see any voltage output even though HAL Configuration shows the velocity-cmd changing. I probed many other pins on the 7i85s in case I just had the wrong ones, but all I seem to get is a constant 5V or 0V.

What am I doing wrong? Thanks!

The hal file has the stepgen set into position mode:

setp hm2_7i92.0.stepgen.00.control-type 0

it should be:

setp hm2_7i92.0.stepgen.00.control-type 1

for velocity mode

Also the P term for the stepgen should be 1000, not 50

Thanks for the suggestion. I made both these changes, but still no STEP/DIR signal coming from the 7i85s pins. I'm working on drawing a wiring diagram of my setup to help with the debugging. Any other ideas in the meantime?

Well this seems odd since you would normally connect the 7I85S to P1 of the
7I92 with a flat cable (HDR26 to DB25M):

"7i85s is connected to the 7i77 by RS422 CAT5 cable."

ok, I was under the impression I was supposed to use the RS422 smartserial connection. I'll order one of these cables and give it a try.

This worked, thank you!

So the solution was to use an HDR26 to DB25M cable from the 7i92 to the 7i85s, rather than wiring the 7i77 to the 7i85s through the RS-422 interface.

Yes, the RS-422 connection on the 7I85S is an interface for add-on sserial I/O cards