Experimental Physics and
Industrial Control System

"Mark Rivers" <[email protected]> · Fri, 12 Dec 2003 09:22:44 -0600

> The OMS VME58 card, which is normally used in EPICS for 
> motion control, supports such synchronized moves, but this is 
> (to my knowledge and experience) not supported via EPICS motor record 
> and device support.

I have written EPICS software to do coordinated motion with the Newport MM4000/MM4005 motor controller.  This controller is more sophisticated than the OMS58, but even the OMS58 can handle what you need to do.  The software is at:
http://www.cars.uchicago.edu/software/epics/trajectoryScan.html

It's been on my long-term list of things to do to write a version of this software for the OMS58.  It would let people running diffractometers with OMS58 controllers collect data "on-the-fly" even if the motion involves multiple motors with non-linear relationships.

I also agree with Mohan and others that simply synchronizing 2 EPICS motors with standard software (e.g. fanout record) will probably work fine.  If the consequence of lack of synchronization is very serious (e.g. crushing vacuum chamber) then there should probably be a PLC or hardware based backup to kill motor power if the tilt gets to be too large.  We do that with a 6 ton high-pressure device that needs to move a large amount vertically, but which must not be allowed to tilt very much.

Mark Rivers

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System