Experimental Physics and
Industrial Control System

"Pearson, Matthew R." <[email protected]> · Wed, 6 Aug 2014 20:15:19 +0000

Hi Ron,

This shouldn't affect the asyn motor drivers, since they tend to wrap velocity commands in with a move function. So the driver controls the order in which the commands are sent, rather than the motor record.

Cheers,
Matt

On Aug 6, 2014, at 4:08 PM, Ron Sluiter <[email protected]>
 wrote:

> Correction...
> 
> When the application tries to set base velocity at or ABOVE the slew velocity of the previous move, a command error occurs.
> 
> Thanks Kurt
> 
> On 8/6/2014 2:59 PM, Ron Sluiter wrote:
>> 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
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System