Re: Question about asynMotor record, limits

[Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>]

Hi Boris,

The problem is that the software limit checking is done in the EPICS motor record, not in the driver.  The motor record does send those limits to the driver, because in some cases the controller can also act on them.  But writing those values to the controller as you are doing does not set them in the motor record.  Your program should set the limits in the record, not in the driver.

Mark

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Borys Lysyansky via Tech-talk <tech-talk at aps.anl.gov>
Sent: Friday, April 21, 2023 5:33 AM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Question about asynMotor record, limits

 

I have the following problem:

I have my asynMotor record with the following lines in
motor.substitutions:

{P,     N,   M,        DTYP,        PORT,             ADDR,  DESC,          EGU,   DIR,  VELO,  VBAS,  ACCL, BDST,  BVEL, BACC,  MRES,  PREC,   DHLM, DLLM, INIT}
{PREFIX:,  1,  "WL",         "asynMotor",  MyController,  0,  "motor $(N)",  nm,    Pos,  .0,   .0,    .0,    0,     1,    .2,    1e-6,     6,       17,     2,  "0"}

During the program run I would like to change the motor limits, which are now 2..17 with
the following code:

auto status1 = m_pAxes[0]->setDoubleParam(motorLowLimit_, newLowValue * 1e6);
auto status2 = m_pAxes[0]->setDoubleParam(motorHighLimit_, newHighValue * 1e6);

Both obtained status are asynSuccess. I have also checked the result by
calling

double lowLimit = 0, highLimit= 0;

getDoubleParam (0, motorLowLimit_,     &lowLimit);
getDoubleParam (0, motorHighLimit_, &highLimit);

It was also correct. However, I would expect that the new low/high limits

should have impact on commands

caput PREFIX:WL.VAL someValue

However, the program behavior here is somehow strange.

Could you, please, explain me it.

With best wishes,

Boris