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

Subject: State Program misses monitored events
From: Philip Taylor <pbt@ast.cam.ac.uk>
To: Epics Technical List <tech-talk@aps.anl.gov>
Date: Mon, 8 Jul 1996 10:09:33 +0100 (BST)
Recently I have been testing a state program that
is intended to change state when a monitored
database value changes. This change may have only
a brief duration (a few millisecs only) before
reverting to a previous value. I was surprised
to discover that when the state program runs on the
same IOC as the database then it would often *miss*
the short duration states. When I ran the program
on another IOC then it never missed them, however
short the duration.

It appears that by increasing the priority of the
state program to be above that of any record 
scanning processing I can improve the situation.
This seems to show that the state program misses 
events when blocked by higher priority record 
processing.

I had imagined that the monitored events were queued
and so I could never miss one - is this not the
case when a state program is monitoring variables
local to the IOC?

Philip

------------------------------------------------------------
Philip Taylor, Royal Greenwich Observatory, 
Madingley Road, CAMBRIDGE. CB3 0EZ. UK
Email : pbt@ast.cam.ac.uk      Phone : (UK+) (0)1223-374710
------------------------------------------------------------


Replies:
Re: State Program misses monitored events Jeff Hill

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