Re: Phoebus alarm does not honor filter

["Kasemir, Kay via Tech-talk" <tech-talk at aps.anl.gov>]

Well, I can't reproduce this.
Under https://github.com/ControlSystemStudio/phoebus/tree/master/app/alarm/examples, there's a demo.db and associated display.
I'm running a softIoc with that demo.db, add the test_alarm PV with enabling filter "test_enable>0" to the alarm tree, and then use the demo.bob display for the following: 

1) Set test_alarm = 10, it shows up as MAJOR alarm in alarm table and tree
2) Set test_enable to 0. test_alarm is shown in gray with "(disabled)" in alarm tree, and not at all in alarm table
3) Set test_enable back to 1, and test_alarm shows back up as it looked in step 1

Did you somewhere configure the alarm server to run with the CA mask set to only pass alarm changes?
There is a preference setting https://control-system-studio.readthedocs.io/en/latest/preference_properties.html

org.phoebus.pv.ca/monitor_mask=ALARM

If you set that, the alarm server will subscribe to PVs by only listening to alarm severity changes.
That's more efficient than monitoring any VALUE changes, but also means that the PVs used in filters will only send a new value when they change alarm state.

The default is thus

org.phoebus.pv.ca/monitor_mask=VALUE

for filters to "work".

-Kay



From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Zhang, Tong via Tech-talk <tech-talk at aps.anl.gov>
Sent: Wednesday, June 8, 2022 2:37 PM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: [EXTERNAL] Phoebus alarm does not honor filter 
 
Dear Colleagues,
 
Recently, when I was working with Phoebus Alarm system to develop the alarms, I found the alarm filter does not work as expected, here is the example:
 
Let’s say ‘alm_pv’ is a non-latched alarm PV, and ‘alm_pv_filter’ is the filter PV which is used to enable/disable ‘alm_pv’;
The filter is “alm_pv_filter==1”, ‘alm_pv_fitler’ is initialized with 1, ‘alm_pv’ is set to 1 (1 is MAJOR, and 0.5 is MINOR, 0 is OK)
>From the Phoebus Alarm table, I see ‘alm_pv’ is major, and listed in the alarm table;
Now I set ‘alm_pv_filter’ as 0 to disable alarm ‘alm_pv’, I see ‘alm_pv’ is removed from the alarm table;
Now I set ‘alm_pv_filter’ as 1 to enable alarm ‘alm_pv’ again, and expected that the ‘alm_pv’ would be showing up in the alarm table again, but it was not! It does not show up, until, see next line;
Then I changed ‘alm_pv’ to 0 to make it OK, and changed it to MAJOR again by setting with 1, it appeared in the alarm table again.
 
So it seems that alarm is only triggered when the status is changed.
Is that true that what 5. described is exactly how the Phoebus alarm system works?
 
Thanks,
Tong