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<== Date ==> <== Thread ==>

Subject: CA monitoring weirdness for status/severity
From: "Hogben, Colin H" <[email protected]>
To: "[email protected]" <[email protected]>
Date: Mon, 07 Aug 2017 10:58:32 +0100
Hi,
Here at JET, I'm developing bridges (both directions) between EPICS Channel Access and our home-grown Object Monitoring System. I've come across what to me seems like unexpected behaviour, which I can demonstrate with standard CA tools.

First I start softIoc with the following database:

  record(ao, "chah:ao") {
    field(HIGH, 10)
  }

Next, I monitor the HIGH field:

  gen-pub-11:~ $ camonitor chah:ao.HIGH
  chah:ao.HIGH                   <undefined> 10 UDF INVALID

My first surprise is that the HIGH field is reported as undefined, when it clearly has the value I configured. But it gets weirder. I now do a

  caput chah:ao.HIGH 11

and the camonitor spits out an update:

  chah:ao.HIGH                   <undefined> 11 UDF INVALID

However, if I start a new camonitor, I get

  gen-pub-11:~ $ camonitor chah:ao.HIGH
  chah:ao.HIGH                   2017-08-07 10:30:55.033976 11

So is it undefined or not? I find it surprising that the last output from camonitor should differ depending on when I start it.

Any illumination welcome!
--
Colin Hogben
Professional Software/Control Engineer
CODAS & IT Department
United Kingdom Atomic Energy Authority
Culham Science Centre
Abingdon
Oxfordshire
OX14 3DB
Tel : 01235 464948
Web: www.gov.uk/ukaea

Replies:
Re: CA monitoring weirdness for status/severity Johnson, Andrew N.

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