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Entry  Thu Aug 1 03:34:35 2013, Chloe, DailyProgress, ECDL, Assembling ECDL 
    Reply  Thu Aug 1 18:33:12 2013, Chloe, DailyProgress, ECDL, Assembling ECDL tempsensor.PNG
       Reply  Fri Aug 2 18:15:06 2013, Chloe, DailyProgress, ECDL, Assembling ECDL possible_tec_mount.PNG
          Reply  Mon Aug 5 18:47:04 2013, Chloe, DailyProgress, ECDL, Assembling ECDL heating.PNGcooling.PNGnoise_beginning.JPG
             Reply  Tue Aug 6 19:48:19 2013, Chloe, DailyProgress, ECDL, Assembling ECDL 100_0079.JPG
                Reply  Wed Aug 7 18:13:21 2013, Chloe, DailyProgress, ECDL, Assembling ECDL 
                   Reply  Thu Aug 8 18:43:44 2013, Chloe, DailyProgress, ECDL, Assembling ECDL 100_0081.JPGcool_bridge.PNGheat_bridge.PNG
                      Reply  Fri Aug 9 18:01:47 2013, Chloe, DailyProgress, ECDL, Assembling ECDL cool_bridge2.PNGheat_bridge2.PNG
                         Reply  Tue Aug 13 18:13:35 2013, Chloe, DailyProgress, ECDL, Assembling ECDL 
                            Reply  Thu Aug 15 18:53:45 2013, Chloe, DailyProgress, ECDL, Assembling ECDL 100_0104.JPG
Message ID: 1273     Entry time: Thu Aug 1 18:33:12 2013     In reply to: 1272     Reply to this: 1277
Author: Chloe 
Type: DailyProgress 
Category: ECDL 
Subject: Assembling ECDL 

Today I tried to set up the TEC on the actual assembly. When doing so, Tara pointed out that I needed to have a separate temperature sensor to monitor the TEC, and to use to calibrate the PID gain on the TEC controller. 

I built a simple temperature sensor with a 10k thermistor. The temperature can be determined by measuring Vout and determining RT. Once RT is determined, this can be converted into a temperature using the information on the data sheet for the 10k thermistor. The schematic is attached. I chose the value for R0 based on what would maximize the difference in Vout for a 1 degree C fluctuation about room temperature (25 C) which is what will be used to tune the PID gain. I chose Vin based on what would make the signal have fluctuations of about 500 mV, which is what is needed to be readable on an oscilloscope. Once I built this circuit, I tested it. It is sensitive to temperature changes, since the output voltage changed when I covered the thermistor with my hand.

Tonight I am going to incorporate changes Tara suggested for my progress report. The updated version will be put on the SVN. Tomorrow I will try to the temperature sensor I built today to calibrate the PID gain on the TEC controller. 

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