[Dsg-ft] Chiller temperature problem

[Raffaella De Vita]

Hi Amanda,
thanks a lot for the update; we have been looking at calorimeter 
temperature strip charts in the last days and we guessed that the tests 
on the interlocks were still giving the same weird behavior. We have a 
few questions:
- when you ran tests in the EEL, what was the chiller temperature set 
point? was the chiller connected to the detector with fluid going 
through the full circuit?
- since the analog card was installed we believe by Brian some time ago 
(when we bought the chiller we did not get the analog interface), if 
there is another one available, would it be possible to try replacing 
it? is this a LRZ 912 module?
- have you checked that the analog card is still plugged in properly? 
I'm wondering if it got partially unplugged during transportation to the 
hall.
If it is simpler, we can have a meeting by phone or bluejeans to discuss 
about all this.

In parallel, the back up solution of cutting power is fine with us. We 
can also look into buying another chiller if no other solution can be found.
Thanks,
     Raffaella


Amanda Hoebel wrote:
> Hi,
>
> Tyler, Pablo, Pete, and I have been investigating the temperature problem with the chiller. When "analog input" is enabled, the temperature either increases or decreases rapidly. We have tried to debug this problem and have had no success. We are puzzled by this problem because all features worked as expected when the system was in the EEL building. We believe that the chiller or the Analog Interface card or both are malfunctioning and need to be looked at by the manufacturer.
>
> The SVT had two Lauda chillers bought by Hall B engineering, both of which developed many problems and were unreliable. So, after many repairs, they were replaced with another brand. We suggest the chiller for the FT be replaced as well, because we are concerned that in time, like with the SVT Lauda chillers, even the key parameters that the chiller is outputting for the FT might not work.
>
> In the interim, we can hook up a Bira box that will allow the hardware interlocks to cut power to the chiller instead of turning off the pump with the analog card. Let us know what you plan to do.
>
> Regards,
> Amanda
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