Experimental Physics and
Industrial Control System

Kevin Peterson via Tech-talk <tech-talk at aps.anl.gov> · Tue, 29 Mar 2022 16:24:43 -0500

Bernhard,

With ACCL=2.0 the desired acceleration would be 410 steps/s^2, but the

driver hard-codes the minimum acceleration to 4000 steps/s^2:

https://github.com/epics-motor/motorPhytron/blob/master/phytronApp/src/phytronAxisMotor.h#L21

The minimum acceleration is enforced here:

https://github.com/epics-motor/motorPhytron/blob/9acb974257dc61512017f18f9b823be0495e948d/phytronApp/src/phytronAxisMotor.cpp#L705-L706

I thought the problem might be due to an acceleration time that is

significantly longer than the poll period, which might result in the

controller still decelerating when EPICS sees the limit is hit, but that

doesn't explain the behavior you're seeing.

Does the motor record that fails to home properly have a nonzero

backlash distance (BDST) or a non-zero retry count (RTRY)?

There are only four places in the motor record code where moves are

commanded. One is where normal moves and retries are commanded. The

other three are related to backlash correction.

Kevin

On 3/29/22 09:06, Bernhard.Kuner wrote:

Hallo Kevin,

thank You for the help to understand what happens in the motorRecord,
nasty  beast this record!

The homing type is here on the positive end-switch "Mn.m+". Poll period
0.5s but ACCL=2.0

There was a bug in the phyMotion software if you use the positive
end-switch, but there is an update from phytron and now it works if you
give this command by the phyLogic software.

Ok, You say the record recognises a motor action to be done by
pC_->motorStatusDone_  This is set in the poll routine by the command
"Mn.m==H". In the log you can see that there is no "M1.1==H" with the
answer "E" for done after hitting the end-switch and before the new move
comand occurs. So we suppose a problem in the record.

By the way, we have a support for the phytron IO modules. There I
introduced support for stringout -in Record to communicate with the

motor controller. If you send a home command this way, it works as

expected.

Bernhard

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System