Omega CL27 - Manual (Page 41)

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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:
1 1. Remove battery from unit under test (U.U.T.). Refer to Battery
Installation/Replacement instructions in the manual.
1 2. Remove bottom-cover from U.U.T. Refer to Disassembly Instructions.
1 3. 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.
1 4. Install calibration cover in place of bottom-cover.
1 5. Re-install battery.
1 6. Connect U.U.T. to test equipment per Figure 2 using the K-type calibra-
tion cable.
1 7. 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.