Martel Electronics 235 - Manual (Page 53)

OBSERVE THERMOCOUPLE POLARITY. THE RED V/TC TERMINAL OF THE
CALIBRATOR IS THE POSITIVE TERMINAL.
The calibrator should be connected to the device under test using the
same type wire as the thermocouple being simulated. This will cause
any difference in temperature between the calibrator’s reference
terminals and the terminals of the unit under test to be compensated
for automatically.
The ranges, resolutions, and accuracy of the various thermocouples can
be found on page 86.
Output functions
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