Experimental Physics and
Industrial Control System

Matthias Clausen <[email protected]> · Fri, 24 Mar 2006 06:12:20 +0100

Of course we are also using the alarm handler...

It seems that you want to achieve a reliable service which will not be
shut down just because the X-Terminal wend down on which you are running
your alh which collects all the alarms - true?

So the first step was to add the Master/Slave mode to alh.

Now you can run several instances of the alarm handler (with the same
configuration file). This is good - so you can allow that one of the
alh's will shut down. Another one will take over and write the data to disk.

But - if all your systems reboot - or at least those running your alh's?
Ideally you would want to run alh from the command line during system
reboot.

Well we've actually created an alh version from which we stripped all
the X-Windows stuff.

But - in this case it's really a completely new program! alh IS X-Window
and highly dependent from lot's of X-Window features (like the main
execution loop). This version never seriously went into production.
So here's your solution:

Create one or more vnc sessions on your server machines and start your
main alh instances in Master/Slave mode on these machines during startup.

We are starting the main alh instances at least on two machines each in
an individual vnc session.
For the future we want to change the alh message stream from opt-in (as
it is now) to opt-out - any alarm will be sent from the IOC to an alarm
queue. This way you will run a system process in the background which
makes sure that any alarm from an IOC (independent of any configuration
file) will be written to e.g. Oracle or a file.
See attached drawing ...
-Matthias

Ernest L. Williams Jr. wrote:

Hi everyone,
Two questions:
(1) How many sites used the EPICS AlarmHandler.
(2) Has anyone changed the EPICS AlarmHandler to run in daemon mode or
as a service?
This would be a useful mode when the logging option is used.
So, basically we would need a commandline option to enable this and give
us an alhLogger, ah?

Thanks,
Ernest L. Williams Jr.
SNS Control Systems Group
ORNL

--
------------------------------------------------------------------------
Matthias Clausen                         Cryogenic Controls Group(MKS-2)
phone:  +49-40-8998-3256                Deutsches Elektronen Synchrotron
fax:    +49-40-8994-3256                                    Notkestr. 85
e-mail: [email protected]                           22607 Hamburg
WWW-MKS2.desy.de                                                 Germany
------------------------------------------------------------------------

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System