Experimental Physics and
Industrial Control System

GAGET Alexis via Tech-talk <tech-talk at aps.anl.gov> · Wed, 2 Nov 2022 09:41:57 +0000

Hi,
To get all information about record I use the "obsolete" following page (that is quite updated anyway ...) : https://wiki-ext.aps.anl.gov/epics/index.php?title=User_Documentation
I haven't found better documentation about it for now:
For your case :
https://epics.anl.gov/base/R7-0/4-docs/calcRecord.html#Expression

CALC can be practical but for limited cases, in your case you can use an "aSub" (C subroutine) or imbricated CALC or also ALARM mechanism (the cleaner way in my opinion).
I think using ALARM you can even get a CALC record without any CALC field expression, something like that, the MS means maximized severity, and your calc will take the upper ALARM level. (MINOR if one of the INP is beyond its limits) (https://docs.epics-controls.org/en/latest/guides/EPICS_Process_Database_Concepts.html) 

record(ai, "$(detector)_wib$(crate)0$(wib)/vcc") {
    field(HIGH, "5.2")
    field(LOW,  "4.6")
    field(HSV, "MINOR")
    field(LSV,  "MINOR")
}
Etc ...

record(calc,"$(detector)_wib$(crate)0$(wib)/calc")
{
      field(SCAN,"5 second")
      field(INPA,"$(detector)_wib$(crate)0$(wib)/vcc MS")
      field(INPB,"$(detector)_wib$(crate)0$(wib)/v1 MS")
      field(INPC,"$(detector)_wib$(crate)0$(wib)/v2 MS")
      field(INPD,"$(detector)_wib$(crate)0$(wib)/v3 MS")
      field(INPE,"$(detector)_wib$(crate)0$(wib)/v4 MS")
}

I haven't tested it, but it should work

Cheers

Alexis GAGET
CEA Saclay - DRF/Irfu/DIS/LDISC

-----Message d'origine-----
De : Tech-talk <tech-talk-bounces at aps.anl.gov> De la part de Meddage, Varuna via Tech-talk
Envoyé : mardi 1 novembre 2022 16:08
À : tech-talk at aps.anl.gov
Objet : calc type record question

Hi,

I have following "calc" type record in one of my .db files.

===============================================================

record(calc,"$(detector)_wib$(crate)0$(wib)/calc")
{
      field(SCAN,"5 second")
      field(CALC,"((A>=4.6&&A<=5.2)&&(B>=4.6&&B<=5.2)&&(C>=1.75&&C<=1.80)&&(D>=3.2&&D<=3.4)&&(E>=0.7&&E<=2.0))?1:0")
      field(INPA,"$(detector)_wib$(crate)0$(wib)/vcc")
      field(INPB,"$(detector)_wib$(crate)0$(wib)/v1")
      field(INPC,"$(detector)_wib$(crate)0$(wib)/v2")
      field(INPD,"$(detector)_wib$(crate)0$(wib)/v3")
      field(INPE,"$(detector)_wib$(crate)0$(wib)/v4")
      field(DESC,"")
      field(HIHI,"")
      field(HIGH,"")
      field(LOW,"")
      field(LOLO,"")
      field(MDEL,"-1")
      field(ADEL,"-1")
      field(OOPT,"Every Time")
      field(PREC,"6")
}

===============================================================

When I run the EPICS, then I get an error message saying "String is too long" complaining about the expression, I inserted inside the "CALC" field in this record. But when I reduced the number of input PVs of this record from 5 to 4 and rewrite the expression inside "CALC" field, then there is no error.

Is there maximum number of input PVs, that I can use inside a "calc" type record ?

Any help to understand this issue is highly appreciated.

Thanks

Varuna Meddage

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System