ATS 2140-M Series, Instruction Manual

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Section 8: Accessories
8.1 Thermocouples
8.1.1 Thermocouple Batch Calibration
The system is set up to use any standard NIST-specified thermocouple type. Simply by selecting, during
the setup procedure, the type of thermocouple wire used, the temperature readout will be correct for
an ideal perfect thermocouple. Because no thermocouple ideal exists, it is common practice to calibrate
the actual thermocouple and provide a chart of actual temperature, indicated temperature, and offset.
The calibration information can be entered with an identifying Batch name. Every time a thermocouple is
made from this particular batch of wire used, the system will correct temperatures using this calibration
information. Completing this calibration process will ensure that temperatures are corrected across
different batches of wire. See the instructions below on how to create a batch.
If uncalibrated thermocouples are used, select the Zero Offset Batch Name, and the system will assume a
perfect NIST Thermocouple.
Typically, the thermocouple is tested at several temperatures over the useful range of the thermocouple
wire type and a chart is provided as a calibration record (see below). Sometimes an error is reported, as
in the following example. At other times, the program will present the error as a correction factor, which
will return the temperature to the NIST profile.
True Temperature (°Celsius) Measured Temperature Offset/Deviation
200 199.40 +0.60
400 399.50 +0.50
600 599.60 +0.40
800 800.10 -0.10
1000 1000.00 0.00
1200 1200.20 -0.02
NOTE: The Actual Temperature is the sum of the Measured Temperature and the Offset.
The system will simply add the measured temperature and the offset. If the previous offsets were
entered into the batch file, the correction would be opposite of the desired effect.
The operator must, therefore, examine the calibration report carefully and make sure the sign of the
correction factor is entered properly.
NOTE: Care must be taken to ensure the test temperature is within the calibrated range. If the measured
temperature drops below the minimum or rises above the maximum, a correction factor will not be
applied.