Omega 24 - Manual (Page 30)

B. RESISTANCE CALIBRATION
NOTE: Thermocouple and resistance calibrations are independent. However,
potentiometer P1 is used in both thermocouple and resistance calibrations to set
EEPROM constants. Follow calibration procedures carefully to ensure that
thermocouple and resistance calibrations do not disturb one another.
Test Equipment Required:
1. Resistance Decades (General Resistance RTD-100, RTD-500/1000, and
RDS-54, or equivalent).
2. Current Source (Fluke 5101B, or equivalent).
3. Digital Multimeter (OMEGA OM7551, or equivalent).
4. Calibration cables per Figure 14.
Ambient Conditions:
Unit should be calibrated at an ambient temperature of 23°C±1°C, with rela-
tive humidity less than 80%.
Preparation For Calibration:
1. Turn off unit, and remove bottom-cover. Refer to Disassembly Instructions.
2. Secure battery with a piece of adhesive tape.
NOTE: Momentary loss of battery power during the following calibration
will invalidate previous adjustments, both resistance and thermocouple.
3. Hook up test-equipment and unit per Figure 14.
4. Set current-source to 1mA, STANDBY mode.
5. Set DMM to 2V DC range.
6. Turn on unit.
7. Set unit to METER mode, RTD-100, °F.
8. Turn off unit. Remove jumper J1. Turn on unit. 'RTD' annunciator should
be flashing.
NOTES: Flashing 'RTD' indicates that calibration adjustments
will be written to memory. Avoid selecting thermocouple
functions while in this mode.
Should it be necessary to scroll through thermocouple
functions, first hit the OPR key (disables flashing 'RTD'),
and start again at Step 7 above.
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