[Dsg-ft] Sensors not working

[Amanda Hoebel]

Hi Raffaella,

Thank you for your reply. We measured infinite resistance on the sensor cables. Let me know what you find out for the sensors. Until the sensors are fixed there is nothing we can do for them on our end. 

When cooling from room temperature, should the chiller always first go to about 10 C and then to 6 C? We can keep that in mind for future times when the chiller needs to chill from room temperature.

Thanks,
Amanda

----- Original Message -----
From: "raffaella devita" <Raffaella.Devita at ge.infn.it>
To: "Amanda Hoebel" <amandah at jlab.org>, "dsg-ft" <dsg-ft at jlab.org>
Sent: Wednesday, November 1, 2017 3:05:39 PM
Subject: Re: [Dsg-ft] Sensors not working

Hi Amanda,
> We noticed at around 2:50pm Tuesday Oct 31 the calorimeter temperature sensors stopped working. Attached is a screenshot of the hardware interlocks and the MYA temperature data. We have inspected the cables on the cRIO end and could not find a resistance indicating that the temperature sensors are connected on the detector end. Would you or anyone else know if someone disconnected the sensors somehow? It is time-sensitive to figure out this problem, as there will be more installations into the assembly and we would not be able to reach the cables.
when inspecting the temperature sensors cables on the cRio end, do you 
measure 0 or infinite resistance?
I will ask about the cables being disconnected for some reason and let 
you know.
> Also we noticed when we enable the chiller after it has been off for a while, the temperature is cooled from about 20C down past 6C. It has gotten to 5C before we turned the chiller off, since we were unsure of how cold it could get without harming anything. I think if left alone the chiller would even out to 6C but would like to know how cold we can allow for it to get to make sure it eventually returns to 6C.
I think as you said the chiller would leveled off at 6 C and, if it goes 
below 6 by 1-2 deg, that it is still ok. Usually, to avoid this when 
cooling down from room temperature, we were use to go first at some 
intermediate setpoint like 10 deg and then go to the final setpoint.

Best regards,
     Raffaella