Experimental Physics and
Industrial Control System

On Dec 6, 2021, at 2:43 PM, Daykin, Evan via Tech-talk <tech-talk at aps.anl.gov> wrote:

Hi Tech Talk,

 

I have a set of three records on my IOC which asynchronously send outputs to a hardware device, call them “A, B and C”. When one of these three processes, the other two should also process.

 

My normal idiom is as follows:

 

record(ao, "A")

{

  …

  field(FLNK, "B")

}

 

record(ao, "B")

{

  …

  field(FLNK, "C")

}

 

record(ao, "C")

{

  …

  field(FLNK, "A")

}

 

Which always works fine if the records are Soft Channels, since all three are in the same lock set and the loop is smart enough to terminate. In my case where all three go to (slow) hardware, this continues infinitely. I see here (https://epics.anl.gov/tech-talk/2006/msg00216.php)  that this was known behavior in 2006, but I’d like to see if there are any alternatives or workarounds in the following 15 or so years.

 

Thank you,

Evan

 

Evan Daykin Controls Engineer Facility for Rare Isotope Beams Michigan State University 640 South Shaw Lane East Lansing, MI 48824, USA Tel. 517-908-7678 Email: daykin at frib.msu.edu

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