Service, Repair And Parts; Recalibration Of The Trx-Ii - GE Druck TRX-II User Manual

SERVICE, REPAIR AND PARTS

Recalibration of the TRX-II

Leave the cursor at NONE in the MEASURE and SOURCE menu
and press the # and EXE keys simultaneously to open the set-up
menu. Select CALIBRATION and press EXE. Fill out the access
code and press EXE to open the calibration menu. The access code
is programmable and works as a barrier to prevent accidental access
to TRX-II calibration ranges.
The calibration menu shows all relevant ranges to calibrate. Each
range can be recalibrated independent of any other range. Only the
cold junction compensation system is influenced by millivolts
recalibration. Select the ranges to be calibrated and press EXE.
Follow the instructions on the next screens. Fill out the calibration
readings and press EXE to confirm or to return to the calibration
menu. Select another range to continue recalibration or press CE to
leave the calibration menu.
Cold Junction Compensation Calibration
To recalibrate or check the cold junction measurement system for
both measure and source, use an electronic thermometer with a
maximum error of ±0.07°C (0.13°'F). Remove the compensation wire
fixation screws from the T/C terminals. Insert the thermometer probe
in the appropriate T/C terminal hole and make sure a good thermal
contact is made down at the bottom of the terminal. Take
measurements samples of both terminals and calculate the average
temperature. Enter this temperature to recalibrate. Do not use
thermal conductivity gel as this cannot easily be removed from the
terminal.
Note:
1. Calibration standards should have a valid calibration certification
and should be at least 3 times more accurate than the published
accuracies for the TRX-II for each range.
2. As derived from electrical parameters, temperature sensor
ranges do not require any individual recalibration.
3. Be sure that you use the test leads, as standard supplied with the
TRX-II or other low e.m.f. test leads.
4. The TRX-II should be powered from the on board batteries during
recalibration.
5. Recalibration must be carried out at reference ambient
temperature and humidity. TRX-II must be exposed to this
condition for at least 2 hours before the actual recalibration starts.
6. Recalibrate mV ranges before starting recalibration of the Cold
Junction Compensation system.
7. When accessing the calibration menu the temperature unit is set
to °C and the temperature scale is set to IPTS 68.
8. Calibration is recommended between 12 and 14 months.
K319 Issue 2 EN-39