Re: Motor Module, Deferred Movement, .VAL field set to .RBV after motion

[Ron Sluiter <sluiter@aps.anl.gov>]

Hello Jacob,

What version (VERS field) of the motor record are you using?

The folks at Diamond are the experts in the use of the motor record 
deferred move function. I defer to them on this topic.

Ron

On 6/29/2016 1:32 PM, Jacob DeFilippis wrote:
> Hello,
>     I am working on implementing a multiple axis synchronized motion 
> using the motor module's asynController base class (model 3). The move 
> function is set up such that  it stores the .VAL to variables inside 
> the physical controller when the deferredMove flag is 1, and when 
> there is a transition from 1-> 0 on the flag I issue the controller 
> command that moves the motors synchronously to the commanded target.
>
>     My problem is when the move completes the .VAL field is set to the 
> .RBV field.  This happens when the .DMOV is returned to 1. I tracked 
> down the cause, which is found in motorRecord.cc in function  
> postProcess(motorRecord * pmr) line 762 (In the github repo). It 
> executes "pmr->val = pmr->rbv" . I am unsure why this postprocess is 
> occurring.  Is there anything extra I should implement in my function 
> that issues synchronized motion?  or possibly something extra in the 
> polling function. Is this because the RTRY field is set to 0?
>
> An example of the bad behavior:
> SMOTOR:AXIS:1.VAL                 2016-06-29 11:05:24.259733 4
> SMOTOR:AXIS:1.DMOV            2016-06-29 11:05:24.474977 1
> SMOTOR:AXIS:1.RBV                2016-06-29 11:05:27.892752 3.0181
> SMOTOR:AXIS:1.DMOV            2016-06-29 11:05:27.892752 0
> SMOTOR:AXIS:1.RBV                2016-06-29 11:05:30.090092 3.4665
> SMOTOR:AXIS:1.RBV                2016-06-29 11:05:32.287451 3.9155
> SMOTOR:AXIS:1.RBV                2016-06-29 11:05:34.484984 3.9993
> SMOTOR:AXIS:1.VAL                 2016-06-29 11:05:34.484984 3.9993 
> <--My problem
> SMOTOR:AXIS:1.DMOV            2016-06-29 11:05:34.484984 1
>
> My motor record
> record(motor, "$(P):$(M):$(ADDR)") {
>   field(SCAN, "Passive")
>   field(DTYP, "asynMotor")
>   field(DISS, "NO_ALARM")
>   field(DIR, "$(DIR)")
>   field(VELO, "$(VELO)")
>   field(VBAS, "$(VBAS)")
>   field(VMAX, "$(VMAX)")
>   field(URIP, "No")
>   field(PREC, "4")
>   field(EGU, "mm")
>   field(MRES, "$(MRES)")
>   field(OUT, "@asyn($(PORT),$(ADDR))")
>   field(TWV, ".1")
>   field(ASG, "MC_MAINT")
>   field(FOFF, "Frozen")
>   field(PRIO, "HIGH")
>   field(OMSL, "closed_loop")
>   field(RTRY, "0")
> }
>
> My function that triggers synchronized motion
> asynStatus Axis::processDeferredMoves()
> {
>   asynStatus status;
>
>   /*resets controller flag*/
>    status = resetFlags();
>    if(status) goto skip;
>
>   /*sends command to start synchronized motion*/
>    sprintf(pC_->outString_,GOSYNC);
>    status = pC_->writeController();
>
>    skip:
>    setIntegerParam(pC_->motorStatusDone_, 0);
>    setIntegerParam(pC_->motorStatusCommsError_, status ? 1:0);
>    callParamCallbacks();
>    pC_->wakeupPoller();
>    return asynSuccess;
> }
>
> Thanks in advance,
> Jacob