EPICS Controls Argonne National Laboratory

Experimental Physics and
Industrial Control System

1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  <20102011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024  Index 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  <20102011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
<== Date ==> <== Thread ==>

Subject: Re: Analog Input records, Stream Device, and INVALID Alarms
From: Dirk Zimoch <[email protected]>
To: Dave Reid <[email protected]>
Cc: [email protected]
Date: Tue, 20 Apr 2010 11:58:22 +0200
Hi Dave,

StreamDevice sets record to INVALID state when there was a communication problem (timeout, errors reported from asynDriver, parsing errors). Whenever the device support is not able to fetch the valid value from the hardware the record becomes INVALID to signal that the value is not trustworthy. The STAT field and probably error messages on the IOC will tell you more about the reason.

This should not break the processing chain. The ai record should have finished its processing being INVALID and processing should continue with the FLNK, monitors, etc.

Normally the record recovers when the record is processed the next time and the hardware sends a value. How do you process the ai record? It may help if you describe your processing chain.

An input record has no IVOA field because it does not do any output actions. To do something similar you can read the value with an ao or calcout record with MS in the input link (DOL or INPA) and use IVOA of that record. It depends on what you want to do in case reading the value fails.

Best regards,
Dirk


Dave Reid wrote:

I have a database that communicates via RS-232 to a vacuum gauge controller. I do this by setting up an Analog In record, that has the DTYP set to "stream". These Analog In records are part of a processing chain in the database.


What happens is that one of my AI records goes into the "Invalid" alarm state, and this breaks the processing chain, and the only way we have been able to recover from this is to reboot the IOC.

So the questions are:
1-Why are we getting into this alarm state? Is this something that the stream device support is doing?
2-How does one recover gracefully from an "Invalid" alarm state?
3-Why is there not an "IVOA" field for input records?


Thanks....

dave



References:
Analog Input records, Stream Device, and INVALID Alarms Dave Reid

Navigate by Date:
Prev: Re: writing to aao crashes ioc Dirk Zimoch
Next: Re: writing to aao crashes ioc Benjamin Franksen
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  <20102011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
Navigate by Thread:
Prev: Analog Input records, Stream Device, and INVALID Alarms Dave Reid
Next: Asyn Question Szalata, Zenon M.
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  <20102011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
ANJ, 02 Sep 2010 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·