RE: Generating a 'binary output pulse' by processing an ao record? [SEC=UNCLASSIFIED]

["LYNCH, Damien" <dly@ansto.gov.au>]

Hi Niklas,

 

It looks like when you have a constant in YY’s DOL it is only retrieved when the record initialises. Have a look at init_record() and process() in src/rec/boRecord.c. So after the first time YY processes it’s VAL will remain at 0. One solution is the following. Another might be to set the DOL of YY to a record whose value is always one and FLNK XX to YY. If you only want YY to go high if XX is non-zero you could make ZZ a calc record.

 

record(ao, "XX") {

    field(FLNK, "ZZ")

}

 

record(bo, "ZZ") {

    field(DOL, "1")

    field(OMSL, "closed_loop")

    field(OUT, "YY PP")

}

record(bo, "YY") {

    field(HIGH, "0.5")

    field(ZNAM, "Off")

    field(ONAM, "On")

}

 

Thanks,

Damien

 

From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Nicklas
Sent: Thursday, 19 June 2014 8:08 AM
To: tech-talk@aps.anl.gov
Subject: Generating a 'binary output pulse' by processing an ao record?

 

Dear all,

my name is Nicklas and I am a student at Uppsala University, Sweden, who is currently working for the research facility FREIA, which is designed for research and development of accelerators and instrumentation for accelerator based research.

 

I am new to epics so I would really appreciate some help.

Now to my question; as the subject line suggests, I need help/tips on how to generate a binary output pulse by processing an analog output record, i.e. I want the bo value to be 1 for 0.5 seconds (and then return to 0) each time the analog output is processed. My idea of the database setup was the following:

 

record (ao, "XX") {

  ...

  field(FLNK, "YY")

}

 

record (bo, "YY") {

  ...

  field (DOL, "1")

  field (OMSL, "closed_loop")

  field (HIGH, "0.5")

}

 

This works fine the first time "XX" is processed (using dbpf), but the next time "XX" is processed (using dbpf), it doesn't work.

 

Any tips/thoughts on this would be highly appreciated.

 

Best regards,

 

Nicklas Bjärnhall Prytz,

Engineering Physics Student at FREIA

Uppsala University

Sweden