Experimental Physics and
Industrial Control System

Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov> · Fri, 5 Aug 2022 16:15:39 -0700

On 8/5/22 14:14, Mikhail Yurov via Tech-talk wrote:

Hello everyone,

A) I am trying to pass several (DOUBLE) constants to my aSub record via INPA-U link fields.
I am new to EPICS and follow the app developer guide's makeBaseApp.pl example.

After modifying the dbSubExample.db (with no other changes) to
record(aSub,"$(user):aSubExample")
{
    field(INAM,"myAsubInit")
    field(SNAM,"myAsubProcess")
    field(FTA,"DOUBLE")
    field(NOA,"10")
    field(INPA,"$(user):compressExample CPP")
    field(FTB,"DOUBLE")
    field(NOB,"1")
    field(INPB,"123")
}
I expected that $(user):aSubExample.B value would be set to 123.
What I get back instead is
caget $(user):aSubExample.B
$(user):aSubExample.B           0
while the INPA works as expected. The dbpr shows these links as
INPA: CA_LINK $(user):compressExample CPP NMS                INPB: CONSTANT 123

I am using EPICS R7.0.6.2-DEV.
The only semi relevant thing that I was able to find was the discussion of this bug
https://bugs.launchpad.net/epics-base/+bug/1699445 <https://bugs.launchpad.net/epics-base/+bug/1699445>

Am I doing something wrong or is it expected behavior?

I don't think you are doing anything wrong, nor is this expected behavior.

This isn't a repeat of lp:1699445, though I think it is a bug related to
constant inputs.  In this case specific to aSub.

As a workaround, you could put the 4x alarm levels in 4x "ao" records,
and link them into the "aSub".

B) I intend to use this aSub record as an alarm status for the input waveform record of doubles and have INPB-E as an
equivalent to the HIGH LOW HIHI LOLO fields. The goal is to set the appropriate alarm status to highest severity if any element of
the waveform will fall outside these limits. I was just wondering if something similar has been already implemented?

No there isn't currently any built alarm calculation for arrays.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System