I haven't worked out how to properly tune the internal PI's because I can't work out how to bring linuxCNC into open loop and then command a specific speed in LinuxCNC. I am thinking about using the internal speed command function and toggling this with push buttons. Say set it to 250, -250rpm and then I will be able to jog it back and fourth while looking at the HAL scope.
Nick. What mode are you using ie position or torque etc. Have you seen or read this:-

https://forum.linuxcnc.org/10-advanc...etailed-how-to

I am in the same boat as you and struggling with a following error when using closed loop. Changing closed to open loop is just one change in the hal file.
This is also my first time with halscope