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| <== Date ==> | <== Thread ==> |
|---|
| Subject: | Reversing the order of motor record base and slew velocity commands |
| From: | Ron Sluiter <[email protected]> |
| To: | EPICS <[email protected]> |
| Date: | Wed, 6 Aug 2014 14:59:40 -0500 |
|
I am considering reversing the order in which the motor record
issues base velocity and slew velocity commands to device support.
Currently, whenever the motor record request motor motion it first
issues a command to device support to set the base velocity and then
the slew velocity. I have no record of why that order was chosen. Unfortunately, command errors are occurring with Pro-Dex MAXv controllers when a specific application changes the base velocity. This is because the base velocity is range limited by the slew velocity value (0 <= base < slew). When the application tries to set base velocity at or below the slew velocity of the previous move, a command error occurs. I made a brief survey the EPICS motor module supported motor controllers. Most drivers either do not implement base velocity or use a fixed range. Both New Focus Model 8753 open-loop controllers and Schneider Electric (IMS) MDrive/MForce controllers are like the Pro-Dex MAX in that the base velocity is range limited by the slew velocity value. I find no motor controllers that would "suffer" from this change, so please let me know if you know otherwise. Ron |