Experimental Physics and
Industrial Control System

Kevin Peterson via Tech-talk <tech-talk at aps.anl.gov> · Fri, 13 Nov 2020 16:49:22 -0600

Juliane,

Having an open-loop move command is helpful, though I don't know how to

map steps + frequency to EGU, but not sufficient to make open-loop axes

work well with the motor driver. The motor record expects a feedback

position to be updated by the driver.

It would be fairly easy to write streamDevice support to allow sending

the open-loop move command from EPICS. I don't know how well this would

work if some of the axes on the MCS controller needed open-loop moves

and others work correctly with the EPICS motor driver.

Kevin

On 11/13/20 4:03 PM, Juliane Reinhardt wrote:

Hi Kevin,

we found the ASCII command to move a motor that does not have an encoder
in the SmarAct manual, p70:

Example:
MST0,100,4095,100
Performs 100 steps at full amplitude and 100 Hz on channel 0.

Is that information enough to implement that in the MCS driver for
EPICS? Would you be able to modify the driver or can you assist me in
doing that? I have not experience yet in writing the actual EPICS
drivers. I assume, we would add this option to the move command
beginning in line 502 of the current smarActMCSMotorDriver.cpp

Another naive idea would be to move the motor using the hardware's
step-count register? I tried moving using caput $motor.RVAL but that
doesn't work either. Any options to setup an RDBL Link to read positions
from or does that only over complicate things and we should rather have
the driver adapted?

Thanks for your help,
Juliane

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System