RE: asynMotorAxis

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

Mark

motorApp/Db/asyn_motor.db contains these 3 records (in addition to others).  These are all you need to get the motor record resolution, offset, and direction fields into your driver.

# Motor direction for this axis
record(longout,"$(P)$(M)Direction") {
    field(DESC, "$(M) direction")
    field(DOL,  "$(P)$(M).DIR CP MS")
    field(OMSL, "closed_loop")
    field(DTYP, "asynInt32")
    field(OUT,  "@asyn($(PORT),$(ADDR))MOTOR_REC_DIRECTION")
}


# Motor offset for this axis
record(ao,"$(P)$(M)Offset") {
    field(DESC, "$(M) offset")
    field(DOL,  "$(P)$(M).OFF CP MS")
    field(OMSL, "closed_loop")
    field(DTYP, "asynFloat64")
    field(OUT,  "@asyn($(PORT),$(ADDR))MOTOR_REC_OFFSET")
    field(PREC, "$(PREC)")
}


# Motor resolution for this axis
record(ao,"$(P)$(M)Resolution") {
    field(DESC, "$(M) resolution")
    field(DOL,  "$(P)$(M).MRES CP MS")
    field(OMSL, "closed_loop")
    field(DTYP, "asynFloat64")
    field(OUT,  "@asyn($(PORT),$(ADDR))MOTOR_REC_RESOLUTION")
    field(PREC, "$(PREC)")
}

This is how the Newport XPS driver gets these values.

> And even there: MOTOR_REC_RESOLUTION was unknown, I had to change it to MOTOR_RESOLUTION in the OUT field. Probably a version issue.

No, it is not a version issue.  MOTOR_REC_RESOLUTION is defined in asynMotorController.h.  It is different from MOTOR_RESOLUTION.  MOTOR_REC_RESOLUTION is the MRES field of the motor record.

corvette:~/devel/motor/include>find . -name '*.h' -exec grep -H -i motorrecresolution {} \;
./asynMotorController.h:#define motorRecResolutionString        "MOTOR_REC_RESOLUTION"
./asynMotorController.h:  int motorRecResolution_;

> This exhibited some surprising (to me) features. Or shall I call it bugs?

Please load that provided database and see if you have problems.  I am not convinced there are bugs, just a lack of documentation.

Mark


-----Original Message-----
From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of Koennecke Mark (PSI) via Tech-talk
Sent: Wednesday, February 12, 2020 4:06 AM
To: tech-talk at aps.anl.gov
Subject: asynMotorAxis

Hi,

I finally managed to get the resolution down into my my motor driver. It was an interesting experience. It was NOT enough to implement writeFloat64(). The resolution did not arrive. 
I had it print to me what it was doing and this was interesting:

- On initialization I got a code motorEncResolution_ with infinity value. Obviously not yet initialized. 
- No motorResolution_
- When I tried to manually set MRES, I received motorPosition_ function codes with a newly calculated
  position. No motorResolution_. 

I had to use Giles Knap suggestion with the additional DB field too in order to achieve success. And even
there: MOTOR_REC_RESOLUTION was unknown, I had to change it to MOTOR_RESOLUTION in the OUT field. Probably a version issue. 

This exhibited some surprising (to me) features. Or shall I call it bugs? 

Thanks and Best Regards,

     Mark Koennecke