Recommended hal Setup for CSP Servo Drives

Hi everyone,

I am finally at the point of setting up the hal after an entire rewire of my cabinet. This got me wondering regarding the setup in linuxcnc hal for servos that are in CSP mode.

Setup: Delta A3 servos, connected via linuxcnc-ethercat Deasda driver (refered to as A3)

I would like to work out what the best setup in terms of hal components is to control an axis via CSP and EtherCat.

joint.0 provides motor-pos-cmd and vel-cmd, furthermore, it requires motor-pos-fb. Question now is: Where does the fb come from?
I currently use lcec.0.A3.enc-pos-abs as direct feedback from the drive.

Is this the right way? Should I involve a PID loop somewhere in this? (Asking, because mesa pncconf adds one even though there is no feedback other than the computed position from the stepgen).? How would I expand this if I where to use external encoders (e.g. linear scale)?

(Actually, the questions apply to CSV as well).

Thus far I was always quite sure about my setup, now I am a bit lost. Any input is greatly appreaciated.

fb comes from the encoder so it sounds right to me
Most of us build our hal files by copying a template.
You can copy mine 
github.com/rodw-au/linuxcnc-cia402/tree/main

I don't think PID is required

Thanks Row,
This is similar to earlier test setups of mine (albeit with cia). What makes me wonder though: Why did you keep the PID in the servo thread?

Cheers,
Guido

It was in the template I followed but I never used it.