[evlatests] Mystery temperature swings

[Ray Ferraro]

	There used to be AC power analyzer on the wall, not a temperature 
monitor. I don't believe I have an temperature recorder.
The operator could take a look. Might be hard to detect this variation 
without instrumentation. It should be noted that the outer screen room 
is on building air, though there is some leakage from the inner screen 
room sub floor to the outer screen room sub floor. Some of which, is 
exiting through a cut-out in the floor panel behind the rack.
	Ray,

Bryan Butler wrote:
> do we still have the strip-chart temp log thingie on the wall in the old 
> correlator room?  might be interesting for somebody to have a look at 
> it.  otherwise just ask the operator to go in there around midnight and 
> have a look at what's going on?
> 
> 	-bryan
> 
> 
> 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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-- 
Ray Ferraro
National Radio Astronomy Observatory
Array Operations Center
P.O. Box O
1003 Lopezville Road
Socorro, NM 87801-0387
575-835-7196
fax: 575-835-7027