Following errors after upgrade.

I've been running linuxcnc 2.7 on my mill for a couple years. I recently upgraded to build both linuxcnc and machinekit from source so I can test development work being done in FreeCAD Path workbench.

After building LinuxCNC 2.9, all the tests pass. When I launched the mill configuration, the script prompted for automatic upgrade which I allowed. Now the mill config starts and shows gmoccapy. But when I try to enable the machine, the Z axis moves momentarily and then throws a following error.

I assume this is related to the 2.8 joint/axis merge. Since none of the joint configuration numbers changed, it must need some additional configuration for the joints that I'm missing. Any ideas?

Working machinekit configuration: github.com/sliptonic/millstone/tree/gmoccapy

Failing Linuxcnc configuration: github.com/sliptonic/millstone/tree/linuxcnc-2.9-gmoccapy

I found a minor discrepancy between joint and axis in the max_velocity. Corrected this but it had no effect. Still get the error.

deleting all lines like:

net N-vel-fb => pid.N.command-deriv

Should fix the issue

What PCW said worked in my case.

Yep, that did it. Thank you. I'm curious what's going on here. Perhaps there should be a note on the upgrade wiki page.

is this caused by the Axis/joint conversion updater or by a new wizard config

I think it was caused by an error made by the old configuration wizard, but because of an old bug in the PID component, wasn't noticed until updating to the current version where the PID comp was fixed.

Yep that's basically it. The old PID component ignored its command_deriv input and
always calculated it internally. The new component uses the command derivative
input if its connected to a signal, and uses an internal calculation if its command_deriv
pin is unconnected. The problem is that some versions of pncconf connect an undriven
signal to the PIDs command_deriv pin, making the FF1 tuning term inoperative.

Well I'd suggest using black magic rather then a switch for this PID behavior was the real problem.
In fact I still think it should be changed.
In the very least the black magic should have checked if there was a driving pin connected.


Chris