linear scale feedback with Delta Servo ASD-A2-M in drive or in linuxcnc?

Hello,

Another question for my machine is about closed loop & feedback system. I will use Delta Servos ASD-A2-1021-M for XYZ which can take care about closed loop control. But when powering them off (e.g. when opening main door) they would loose their feedback position and need homing when connected 100% safe.

I would always use servo drives in position pulse input mode but how to get the best out of my feedback devices?

Options and thoughts with pro/con might be:

1) use XYZ linear scales within servo drive and powering power&logic input off when doors are open
+ optimized regulation directly in servo driver (maybe fastest response?)
+ only one rs422 receiver connected, less mesa encoder inputs necessary
- lost position when servo power off (actually a no-go)

2) use XYZ linear scales within servo drive and powering off EXCEPT drive's logic power (that is also 230V)
+ optimized directly in servo driver (maybe fastest response?)
+ position not lost when off
-(-) still connected to 230V logic and maybe unsafe! Maybe limiting power with small power 1:1 transformator helps a bit...?

3) use XYZ linear scales within linuxcnc only
+ simple connection
- maybe slower regulation because it is not optimized directly in servo driver?
- no lost position

4) use XYZ linear scales with servo drive (just incremental use) AND connecting scales to linuxcnc (saving absolute position)
+ optimized directly in servo driver (maybe fastest response?)
+ position not lost when off (using linuxcnc input for absolute position and drive input for optimized positioning - no abs. value necessary)
- two rs422 receivers connected (more cable work)
- maybe unstable due to two pid regulators?
- maybe 3) gives same performance with less effort?


Thanks in advance & best regards,
Alex

Hi/Hallo,

do you found a solution? (Hast du eine Lösung gefunden?)
I also have 3 ASD-A2 and want them to use also with linear scales.

Kind regards/Beste Grüße,
Pierre