Beckhoff: Implement AUTO_ONOFF

[DominicOram]

As a user of a Beckhoff controller I would like the option to set my axes to automatically energise/de-energise between moves or to set them to always be on. This functionality is already there in the GALIL as AUTO_ONOFF. The Beckhoff variable for setting whether the motor is on or not is BENABLE.

Acceptance Criteria

• The user can set OFF_CMD to turn the Beckhoff axis off
• The user can set ON_CMD to turn the Beckhoff axis on
• The user can set AUTOONOFF_CMD to 1 and the Beckhoff axis will turn on before a move and off again after
• The user can set AUTOONOFF_CMD to 0 and the on/off status of the Beckhoff axis will be unchanged by a move
• AUTOONOFF_STATUS and ON_STATUS also exist to show current device status
• These commands, and readbacks are available on the OPI, like with the galil

[FreddieAkeroyd]

Just to clarify, BENABLE is the on/off variable to set, but the "auto" feature needs to be done in our driver? Also is BENABLE read/write i.e. if the motor is turned off via anther route will it update to reflect the current status?

[FreddieAkeroyd]

looks like some autoonoff support is now in motor module https://github.com/ISISComputingGroup/EPICS-motor/blob/ee89b58c93fb5b2388fa28a52ac7c210de71c8b0/motorApp/Db/asyn_auto_power.db

[DominicOram]

Yes, currently we need to do the auto bit ourselves, I'll talk to Simon about whether it makes sense to put it in the PLC. Yes, it's read/write.

[rerpha]

So far what i've got is:

ISISComputingGroup/EPICS-tcIoc#10
ISISComputingGroup/EPICS-ioc#651

note: after testing if this works OK remove the print

[DominicOram]

This looks like it would work if it wasn't for #6874

[rerpha]

#6874 has solved DMOV and MOVN i believe so this may work, i'll test and put in review if it does

[rerpha]

ok, still needs some work, cant seem to get it to disable the axis now for some reason and we need to propagate it through to the GUI, so im going to shelve for now in favour of other work