RE: Epics motor driver dval init

[Paul-Elie GUILLOT via Tech-talk <tech-talk at aps.anl.gov>]

Hej Torsten,
I have solved the issue. On the initial motor-master, not on the motor-master-ess but I think I can do it on the motor-master-ess.
Basically, the issue comes from the fact that one is trying to read the DVAL field of the motor record before it is set according to RRBV which itself is not yet set according to REP or whatever is linked to readback.
Problem is you can't use RRBV or REP either because they are processed later.
For now, my fix is to use:
    double position = pPvt->status.position;
    double encoderposition = pPvt->status.encoderPosition;
which are set thanks to my initHookAfterInitDevSup, processing polling call before the init record.

Thanks to that I can then define:

    double position = pPvt->status.position;
    double encoderposition = pPvt->status.encoderPosition;
    double rdbd = (fabs(pmr->rdbd) < fabs(pmr->mres) ? fabs(pmr->mres) : fabs(pmr->rdbd) );
    int use_rel = (pmr->rtry != 0 && pmr->rmod != motorRMOD_I && (pmr->ueip || pmr->urip));
    int dval_non_zero_pos_near_zero = (fabs(encoderposition*pmr->eres) > rdbd) &&
                                      (pmr->mres != 0) && (fabs(position * pmr->mres) < rdbd);

Basically, just swapping the old pmr->dval by encoderposition

And

    if (initPos)
    {
        double setPos = (encoderposition*pmr->eres) / pmr->mres;

        /* Write setPos to the driver */
        pPvt->pasynUserSync->reason = pPvt->driverReasons[motorPosition];
        status = pasynFloat64SyncIO->write(pPvt->pasynUserSync, setPos, pasynUser->timeout);
        if (status) {
            asynPrint(pasynUser, ASYN_TRACE_ERROR,
                      "devMotorAsyn::init_controller, %s failed to set position to %f\n",
                      pmr->name, setPos );
        } else {
    		asynPrint(pasynUser, ASYN_TRACE_ERROR,"setposish\n");
            asynPrint(pasynUser, ASYN_TRACE_FLOW,
                      "devMotorAsyn::init_controller, %s set position to %f\n",
                      pmr->name, setPos );
        }
    }

This does indeed send the setposition according to the encoder position.
Let me know what you think.
Best Regards

Paul



-----Message d'origine-----
De : Torsten Bögershausen <tboegi at edom.se> 
Envoyé : mardi 13 février 2024 16:16
À : Paul-Elie GUILLOT <peguillot at irelec-alcen.com>
Objet : Re: Epics motor driver dval init

Hej Paul,
now I have some time to dig into the log.
Stay tuned ;-)
/Torsten


On 2024-02-13 16:02, Paul-Elie GUILLOT wrote:
> Sorry haha
> I think I see where you want to treat the rstm but I still have dval 0 
> though it is not
> 
> -----Message d'origine-----
> De : Torsten Bögershausen <tboegi at edom.se> Envoyé : mardi 13 février 
> 2024 14:37 À : Paul-Elie GUILLOT <peguillot at irelec-alcen.com> Objet : 
> Re: Epics motor driver dval init
> 
> Salut Paul,
> 
> good to here, that you made progress.
> I have been "fighting" with the DVAL/RSTM problem for weeks, and there are severe improvements in the ess-motor.
> Including traces ;-)
> 
> Suggestion a)
>     Could you step with a debugger through the code ?
> Or, may be:
>     run your code with the ess-motor version, and send the traces
>     to me ?
> 
> (Or do both ?)
> 
> BR
> /Torsten
> 
> 
> On 2024-02-13 14:10, Paul-Elie GUILLOT via Tech-talk wrote:
>> Hello everyone at tech-talks,
>>
>> Hope you are well.
>>
>> I am on the end of developing my motor driver. I am currently testing it.
>>
>> I have installed Epics on a VM on ubuntu and I am directly talking to 
>> my Hardware motor controller through TCP/IP.
>>
>> The driver I have developed is according to Model 3 Driver.
>>
>> Anyway, I was hoping to use the field of the motor record called RSTM 
>> to set the motor position (stepper counts) according to the DVAL 
>> field(encoder counts).
>>
>> The treatment of the RSTM field seems to be done in the function 
>> init_controller in the devMotorAsyn.c file.
>>
>> However, when called and the function asks for the motor record dval
>> (pmr->dval) the value is equal to 0.
>>
>> I think it is because the pmr->dval = pmr->drbv is done after the 
>> record is initialized.
>>
>> My question is then, does the RSTM field work as it is intended?
>>
>> How can I force Dval to be equal to the encoder position before the 
>> init_record?
>>
>> Thank you for your help and time
>>
>> Best Regards
>>
>> Paul
>>
>> Paul-Elie GUILLOT
>>
>> Technology Manager in Automation and Robotics
>>
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