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Documentation Number TCDA0997 Manual 7
B&B Electronics -- PO Box 1040 -- Ottawa, IL 61350
PH (815) 433-5100 -- FAX (815) 433-5104
Chapter 4: Calibration
Overview
The standard TCDA module is calibrated at the factory for a
temperature range of -50
°C to 200°C. With a resolution of 20mV/°C
and an offset voltage of -1.0VDC. The offset voltage shifts the
negative voltages produced at temperatures below 0
°C to voltage
greater than 0VDC. The TCDA modules that have modified
temperature ranges are not calibrated at the factory. The user must
calibrate these modules. The calibration process described below is
the process used at the factory. The calibration process for a
different temperature range is similar, but the values will differ.
The non-linearity of the thermocouple over the -50
°C to 200°C
range is relatively small, so it is ignored in the factory calibration
process. If you require more accurate readings, you may want to
consider using one of the techniques mentioned in Chapter 2.
Calibration Procedure for Standard TCDA Modules
During the calibration process and while measurements are
being taken, do not touch the terminal blocks or external diodes
near the terminal blocks!
Items required:
1. Small slotted screwdriver.
2. DC voltmeter with 10mV readability (0.01V).
3. Ice slurry - container (cup, glass, etc.) filled with ice and then
add water to cover ice, container of boiling water (be
careful!), or substance of known temperature that can be
used to calibrate the TCDA.
The following steps are used to calibrate channel 1 of the TCDA
module. The TCDA can operate in a temperature between 0
°C and
70
°C. It is a good idea to calibrate the TCDA at the same ambient
temperature that the module will be taking measurements in.
Information in parenthesis ( ) is used for channel 2 calibration.