The CJC sensor is located on the TBX-68T between the two longest connectors and labeled RT1. It is a 5k Ohm(@ 25 C) NTC Thermistor not a IC sensor, so when the temperature increases the resistance will decrease. This thermistor follows the Steinhart-Hart equation found on page 3-20 of the NI4350/4351 User Manual. There is a VI in LabVIEW found in the Functions Palette>DAQ>Signal Conditioning Menu called Convert Thermistor Reading.vi that has the appropriate constants to convert the thermistor resistance to a temperature. When you measure the resistance make sure that your range is above 5500 Ohms. You will also need to make sure that IEX0 switch on the TBX-68T is turned off if you are not making any other resistance measurements. This switch routes the current sou
rce to the CJC thermistor when no other transducers are using the current source.
Do you still get zero readings on the thermocouples if you use a custom CJC instead of the built in?
