[evlatests] Mystery temperature swings

[Bryan Butler]

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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