Experimental Physics and
Industrial Control System

Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov> · Wed, 18 Mar 2020 15:25:02 -0700

FYI. passing NULL instead of a field address to db_post_events()
will post to every subscription on the record regardless of field.
Trying this should give a clear indication if the only problem is
the wrong field address.

I guess the other variable is event mask.  SO

> db_post_events(pscal,NULL,0xf);

should post to every subscriber to this record regardless of field or mask.

On 3/18/20 12:02 PM, Mark Rivers wrote:
> Could this be a problem with EPICS_CA_MAX_ARRAY_BYTES?  What if you do:
> 
> 
> camonitor -#20  det1.SPCT
> 
> 
> ________________________________
> From: Siddons, David <siddons at bnl.gov>
> Sent: Wednesday, March 18, 2020 1:51 PM
> To: Mark Rivers; Michael Davidsaver
> Cc: EPICS Tech-Talk
> Subject: Re: monitors on array variables
> 
> Hi Mark,
> Yes, I did that. THis is essentially an expanded scaler record. In updateCounts I have:
> 
>         Debug(5, "updateCounts: posting scaler values %d\n",0);
>         /* copy and post spectrum values */
>         for (i=0; i<4096; i++) {
>                 if (mca[4096*pscal->monch+i] != spct[i]) {
>                       spct[i]=mca[4096*pscal->monch+i];
>                       }
>          }
>          db_post_events(pscal,&pscal->mca,DBE_VALUE);
>          db_post_events(pscal,&pscal->tdc,DBE_VALUE);
>          db_post_events(pscal,&pscal->spct,DBE_VALUE);
> 
> etc,
> 
> It gives this output:
> ../zDDMRecord.c(818):updateCounts:   called by process()
> ../zDDMRecord.c(830):updateCounts: got counts[] 0
> ../zDDMRecord.c(838):updateCounts: posting scaler values 0
> ../zDDMRecord.c(866):updateCounts: exit 0
> 
> Running camonitor on det1.SPCT reads the initial values and waits. Triggering a change (by changing monch) results in nothing. It just sits there. I can verify that the values have changed by doing a caget, or a dbgf on the console:
> 
> peter@peter-Latitude-E7240: ~/$ caput det1.MONCH 0
> Old : det1.MONCH                     5
> New : det1.MONCH                     0
> peter@peter-Latitude-E7240: ~/$ caget det1.SPCT[1:20]
> det1.SPCT[1:20] 20 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> peter@peter-Latitude-E7240: ~/$ caput det1.MONCH 5
> Old : det1.MONCH                     0
> New : det1.MONCH                     5
> peter@peter-Latitude-E7240:~/$ caget det1.SPCT[1:20]
> det1.SPCT[1:20] 20 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
> 
> 
> I guess I'm doing something dumb, but I can't see it.
> 
> Pete.
> 
> 
> 
> 
> ________________________________
> From: Mark Rivers <rivers at cars.uchicago.edu>
> Sent: Wednesday, March 18, 2020 2:25 PM
> To: Siddons, David <siddons at bnl.gov>; Michael Davidsaver <mdavidsaver at gmail.com>
> Cc: EPICS Tech-Talk <tech-talk at aps.anl.gov>
> Subject: Re: monitors on array variables
> 
> Can you put some debugging to be sure db_post_events is actually being called, while at the same time running camonitor to see if gets an update?
> 
> 
> 
> ________________________________
> From: Siddons, David <siddons at bnl.gov>
> Sent: Wednesday, March 18, 2020 1:09 PM
> To: Michael Davidsaver; Mark Rivers
> Cc: EPICS Tech-Talk
> Subject: Re: monitors on array variables
> 
> .....and I have, in cvt_dbaddr():
> 
>   case zDDMRecordSPCT:{
>       paddr->pfield = (void *)(pzDDM->pspct);
>       paddr->no_elements = 4096; /* One spectrum for real-time display */
>       paddr->field_type = DBF_LONG;
>       paddr->field_size = sizeof(int);
>       paddr->dbr_field_type = DBR_LONG;
>       break;
> 
> 
> Pete.
> 
> 
> ________________________________
> From: Michael Davidsaver <mdavidsaver at gmail.com>
> Sent: Wednesday, March 18, 2020 12:54 PM
> To: Mark Rivers <rivers at cars.uchicago.edu>; Siddons, David <siddons at bnl.gov>
> Cc: EPICS Tech-Talk <tech-talk at aps.anl.gov>
> Subject: Re: monitors on array variables
> 
> On 3/18/20 9:47 AM, Mark Rivers wrote:
>>> by analogy waveformRecord has
>>>> db_post_events(prec, &prec->val, monitor_mask);
>>> note 'val' not 'bptr'.
>>
>>
>> The mca record has worked with no changes in 3.14, 3.15, and 7.0.3 with these lines:
>>
>>
>> mcaRecord.dbd:
>> recordtype(mca) {
>>         include "dbCommon.dbd"
>>         field(VERS,DBF_DOUBLE) {
>>                 prompt("Code Version")
>>                 special(SPC_NOMOD)
>>                 initial("1")
>>         }
>>         field(VAL,DBF_NOACCESS) {
>>                 prompt("Value")
>>                 special(SPC_DBADDR)
>>                 pp(TRUE)
>>                 size(4)
>>                 extra("void *val")
>>         }
>>         field(BPTR,DBF_NOACCESS) {
>>                 prompt("Buffer Pointer")
>>                 special(SPC_NOMOD)
>>                 interest(4)
>>                 size(4)
>>                 extra("void *bptr")
>>         }
>>
>> mcaRecord.c:
>>     if (MARKED(M_VAL)) db_post_events(pmca,pmca->bptr,monitor_mask);
>>
>> So it is posting monitors on the bptr field, not the val field, and it seems to work fine.
>>
>>
>> It looks like Pete is doing what the mca record does, but it is not working.  Why?
> 
> Ah, there is a second piece to the puzzle.
> 
> db_post_events() must be called with whatever address is in DBADDR::pfield
> which by default in this case is '&val' but this can be changed in the
> cvt_dbaddr callback.  Indeed waveformRecord used to do this.
> 
> https://github.com/epics-base/epics-base/commit/92d52cc415599b7dffa7df1f23d5ba8227fb4d3a
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System