[evlatests] Mystery temperature swings

[Jim Jackson]

We have a Campbell Scientific data logger we have used in the 
antennas for similar measurements.  I believe Doug Gerrard has it and 
probably knows the most about setting it up.

There are also some small USB temperature loggers around.  These run 
on batteries, look like a small thumb drive and you plug them into a 
USB port to dump the data.   I don't know who has them - they were 
being used in a few antennas to monitor the HVAC.

Do any of the nearby Cisco network switches have temperature 
monitoring?  I think some of the Cisco boxes around here do. If so, 
you might check them to see if they show the same thing.   James 
Robnett or Fred Dunn would be the best to ask about that.

Jim Jackson


At 10:27 AM 10/16/2008, Kevin Ryan wrote:
>The WIDAR Prototype Correlator (PTC) is in a half-height rack sitting
>in a corner in the outer screen room in the old VLA correlator room.
>It contains 5 boards each with 5 or 6 temperature sensors.  While
>developing software to monitor these temperatures, I've noticed a
>weird oscillation that occurs for a ~ 2-hour period roughly centered
>around midnight local time.  I've asked Ray Ferraro and Bob Broilo
>about it but they did not know of anything that would cause it other
>than that Ray stated that the temperature in that corner is affected
>by the doors opening and closing.
>
>So now I'm asking more people for ideas.  A graph of the temps on one
>board (they are all similar) over the last two days can be seen here:
>http://www.aoc.nrao.edu/asg/widar/temps/mystery-ptc-temps.jpg
>
>The swings from normal daily activity are apparent starting around
>0600 - presumably from the door opening and closing and use of the
>boards for testing - but what about those oscillations around midnight?
>
>It is certainly possible that this is not being caused by ambient
>temperature swings at all; like something going on on the boards
>themselves or possibly even the data gathering system itself.  Can we
>place a recorder near the PTC to monitor its ambient temperature for
>24-hours?
>
>Kevin
>
>
>_______________________________________________
>evlatests mailing list
>evlatests at listmgr.cv.nrao.edu
>http://listmgr.cv.nrao.edu/mailman/listinfo/evlatests