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

  • X1:AUX-LAB_TEMP_K
  • X1:AUX-LAB_TEMP_C
  • X1:AUX-LAB_TEMP_F

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.

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

ELOG V3.1.3-