[evlatests] Mystery temperature swings

[Doug Gerrard]

Kerry Shores and I have already discussed setting up the Campbell 
Scientific datalogger to monitor the temperatures.  We are planning on 
setting it up next week once we know where the monitor points need to be.

Doug

Jim Jackson wrote:
> 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
>>
>>
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