National Instruments SCC-TC02 用户手册

temperature measurements. To make this conversion, complete the 
following steps:

1.

Measure the thermocouple voltage.

a.

Read the thermocouple channel on the E/M Series DAQ device 
V

 [CH(X)].

b.

Calculate the thermocouple voltage by using the following 
formula:

where

 is thermocouple voltage.

 is E/M Series DAQ device voltage.

This step provides proper scaling for the thermocouple amplifier in the 
SCC-TC0X.

2.

Measure the reference-junction (cold-junction) temperature.

a.

Read the thermistor voltage [AI (X

+8)].

b.

Convert the thermistor voltage to cold-junction temperature using 
the formula in the 

3.

Calculate the cold-junction compensation voltage by converting the 
cold-junction temperature from step 2 to a thermocouple voltage. Use 
the polynomial expressions applicable to the type of thermocouple you 
are using.

4.

Apply the cold-junction compensation to the thermocouple reading 
by adding the cold-junction compensation voltage from step 3 to V

.

5.

Calculate the thermocouple temperature by converting the voltage 
result from step 4 to a temperature. Use the polynomial expressions 
applicable to the type of thermocouple you are using. This calculation 
gives you a linearized temperature measurement.

Polynomials are from NIST Monograph 175.

If you are using an SCC-TC02 with an uncompensated SCC panelette, 
temperature gradients between the module and the junctions on the 
panelette affect the accuracy of the measurements.

100

---------------------

=