40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  Cryo Lab eLog  Not logged in ELOG logo
Entry  Wed Apr 18 16:52:48 2018, rana, Misc, General, temperature 
    Reply  Wed Apr 18 20:00:36 2018, johannes, Misc, General, temperature labtemp_trend.png
       Reply  Sat Apr 21 16:59:04 2018, johannes, Misc, General, temperature 
          Reply  Mon Apr 23 10:07:07 2018, johannes, Misc, HVAC, lab temperature 
             Reply  Tue Apr 24 11:42:11 2018, johannes, Misc, HVAC, lab temperature 
                Reply  Thu Apr 26 22:13:13 2018, johannes, Misc, HVAC, lab temperature EPICS channel added AD590_readout.PNGtemp_trend_first_hour.png
                   Reply  Mon Apr 30 10:40:51 2018, johannes, Misc, HVAC, lab temperature EPICS channel added Screenshot_from_2018-04-30_10-40-17.png
Message ID: 2029     Entry time: Thu Apr 26 22:13:13 2018     In reply to: 2023     Reply to this: 2030
Author: johannes 
Type: Misc 
Category: HVAC 
Subject: lab temperature EPICS channel added 

There are now EPICS channels that record the lab temperature - measured by an AD590 I received from Andrew. The readout circuit is the following:

The OpAmp is a LT1012 in single supply configuration. The AD590 is a temperature-dependent current source which delivers 1uA/K. The 10kOhm transimpedance resistor R1 converts that to 10mV/K, and the non-inverting amplifier has a gain of 2 with a lowpass at 15 Hz. This gives a conversion factor of 50 K/V to scale the output back to temperature. I connected the output to channel X1:AUX-ACROXT_AI_15 and created EPICS records


which convert it into the corresponding units. The resolution we get this way is (20 V) / (60000) * (50 K/V) = 16.7 mK. I added instructions for frame builder to log the channels to /opt/rtcds/tst/x1/chans/daq/EPICS.ini. The real-time system was in use, so I didn't want to interfere with anything and haven't restarted the framebuilder process yet, but at the next opportunity it will start logging the lab temperature.

Restarted daqd at 10 am Friday morning. First hour of data:

ELOG V3.1.3-