Martel Electronics 235 - Manual (Page 65)

Calibration of Thermocouple 2-Wire Transmitter
1.
Connect the calibrator as shown in Figure 2.
2.
Select mA input.
3.
Select TC output.
4.
Select the TC type.
5.
Select the appropriate temperature scale.
6.
Enter the “zero” temperature.
7.
The calibrator will now simulate the millivolt output of the
selected thermocouple at the “zero” temperature.
8.
While observing the milliamp input current in the left-hand side of
the display, adjust the unit under test for 4 mA output.
9.
Enter the “full scale” temperature.
10. The calibrator will now simulate the millivolt output of the
selected thermocouple at the “full scale” temperature.
11. While observing the milliamp input current in the left-hand side of
the display, adjust the unit under test for 20 mA output.
12. Repeat steps 6 through 11 until the desired accuracy is achieved.
OBSERVE THERMOCOUPLE POLARITY. THE RED V/TC TERMINAL OF THE
CALIBRATOR IS THE POSITIVE TERMINAL.
Application Notes
230/235 60