Richard Dif Cont Test 04/02/2010


Today turned out to be a nice sunny day, so I got a final day of logging the controller in after all.


I added logging of the two sensor voltages, and relocated the logger collector temperature sensor right next to the one for you controller.  They are both siliconed to near the outer edge of a fin about half way up the collector.


I've got to get to my packing, but a couple quick observations:

- No sign of the anomaly I thought I saw the first day with the switch off coming at too high a voltage difference.  So, maybe it was noise from the probles on the meter.


- Turn on differential in the morning is 1.52V - 1.35V = 17 mv 
Turn off in late afternoon is 1.69V - 1.595V   = 9.5 mv


Note that I powered down the controller and powered it back up again without thinking to reset the turn on differential -- so, maybe it was set to 4F?


I'm guessing that one of the two logger channels is reading a few mv high or low, as the turn off differential on the first day as measured with the volt meter was spot on.


- its pretty neat how it avoided turning off the pump for passing clouds a few times even though the differential got down pretty low -- smart controller :)


- It looks to me like a big cloud rolled in right at the end and ended things with a bang -- collector temperature drops like a stone.


- Interesting how fast the collector temperature is coming up just before pump startup in the early morning.


- Overall, it looks good to me.

The loggers were all set to 1 second reading interval.


Here is the full day plot:


Lines top to bottom:

black             Collector temperature F

Green            Collector sensor voltage Volts

Light purple     Top of tank liquid temp F

Heavy Red      Collector return temperature F

Light purple     Bottom of tank temperature F

Heavy Blue       Collector supply temperature F

Green                 Dif controller tank sensor voltage Volts


The square wave black line is motor on when its up, and pump motor off when it down -- its a logger mounted right on the pump motor.


This used every logger I have but one :)



Blow up of the Morning Startup:






Blow up of the afternoon shutdown:




Gary April 2, 2010