CALIBRATION PROCEDURES
Test Equipment Required:
1.Thermocouple simulator (OMEGA CL25, or equivalent).
2.Microvolt null-meter (Keithley 155, or equivalent)
3.Calibration cover (OMEGA 820-307-4).
4.Calibration cables, T.C. types K, J, T & E (as required) per Figure1 below.
5.Low-thermal (eg. copper) shorting-link for null-meter.
NOTE: The (2) alloy-copper junctions in the calibration cables can be either solder-joints (cleaned to remove flux), or crimp-con- nections. Insulate each junction with heat-shrink tubing, then wrap them close together in copper-foil to ensure that they main- tain identical temperatures (ambient).
Ambient Conditions:
Units should be calibrated at an ambient temperature of 23°C ±1°C, with rel- ative humidity less than 80%. Test equipment and the unit-under-test (U.U.T.) should have 1 hour to reach thermal equilibrium with ambient-tem- perature.
Calibration Adjustments:
11. Remove battery from unit under test (U.U.T.). Refer to Battery Installation/Replacement instructions in the manual.
12. Remove bottom-cover from U.U.T. Refer to Disassembly Instructions.
13. Remove calibration-jumper J1 from printed-circuit board.
NOTE: When installed, J1 protects the contents of EEPROM locations where zero-offset adjustments are stored. Once J1 is removed, this data is erased when the U.U.T. is turned on.
14. Install calibration cover in place of bottom-cover.
15. Re-install battery.
16. Connect U.U.T. to test equipment per Figure 2 using the K-type calibra- tion cable.
17. Turn on U.U.T. and allow 2-3 minutes for thermal re-stabilization of the TC mini-plug and input-jack.
NOTE: • U.U.T. will be in the Type K, °F meter-mode. The FUNC annunciator is on, indicating that new constants will be stored in EEPROM.
