Omega CL27 - Manual (Page 25)

SERVICE INFORMATION
WARNING
All service information is intended for qualified electronic mainte-
nance personnel only.
1. CALIBRATION PROCEDURES
This is a two-part procedure. Products with thermocouple functions only, fol-
low the Thermocouple Calibration procedure below. Products with resistance
functions (RTD, thermistor, ohms) follow first the Thermocouple Calibration
procedure, then the Resistance Calibration procedure.
A. THERMOCOUPLE CALIBRATION
Test Equipment Required:
1. Thermocouple simulator (OMEGA CL521, or equivalent) calibrated to
ITS-90.
2. Microvolt DMM (OMEGA OM7551, or equivalent)
3. Calibration cables, per Figures 11, 12, 13.
NOTE: The copper constantan cables used in Figures 12 and 13
need to be calibrated. Voltage errors in these cables should be com-
pensated at the simulator.
4. Calibration cover (OMEGA 820-307-4).
Ambient Conditions:
Units should be calibrated at an ambient temperature of 23°C ±1°C, with rel-
ative humidity less than 80%.
Preparation for Calibration:
1 1. Remove battery from unit under test (U.U.T.). Refer to Battery
Installation/Replacement section in the manual.
1 2. Remove bottom-cover from U.U.T. Refer to Disassembly Instructions.
1 3. Remove calibration-jumpers J1 and J2 from printed-circuit board.
NOTE: Removal of J1, J2 causes partial loss of previously stored
calibration data. Do not remove these jumpers unless recalibra-
tion is intended.
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