Omega 25, 27, 26, 24 manual Calibration Procedures

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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:

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.

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Contents CL23A, 24, 25, 26 Omega.comTM Table of Contents General Information Common SpecificationsTemperature Coefficient Page Model CL23A/CL23EC Unique SpecificationsModel CL24 Model CL25/CL25ECModel CL27/CL27EC FeaturesManual Addenda Unpacking Your Unit Safety InformationSafety Precautions Page Battery Installation Battery INSTALLATION/REPLACEMENTOperation with Rechargeable Battery Memory BackupProblem Likely Cause Diagnostics and Error MessagesOperating Instructions Initial Turn onKeypad OPR Meter Mode Operation Thermocouples Set-UpHold Meter Mode Operation RTD, Thermistor & Ohms Set-UpData Logging and Recall To Recall Readings To Save ReadingsCalibrator Mode Operation Thermocouples Set-Up To Erase Data Locations Meter ModeCHANGE/ENTER, 2, 1, 2, 0, CHANGE/ENTER Calibrator Mode Operation RTD, Thermistor & Ohms Set-UpWire Resistance Simulation To Store Outputs Storage and Recall of Calibrator SettingsTo Recall Outputs To Erase Set-Up Locations Calibrator ModeRamp Function CL25 and CL27 Step FunctionCalibration Procedures Service InformationThermocouple Calibration Test Equipment Required Ambient ConditionsPage Calibration Adjustments Input Adjust Reading Meter-Mode Zero & Gain Adjustments Sensor StepCalibrator-Mode Zero & Gain Adjustments Sensor Output Adjust ReadingCalibration Setup, Copper Mode Test Equipment Required Resistance CalibrationResistance Calibration Setup Calibration Adjustments Input Adjust Verify Reading Output Input Adjust Verify ReadingCalibration of Meter-Mode Resistance Functions RTD-Thermistor Sensor Unit StepCalibration Verification Equipment Required Model Software RevisionPage Page Alloy Mode Verification Procedure for Thermocouple Functions Page Mechanical Parts Diagram Calibration Procedures Page Page Page Page Page USAWARRANTY/DISCLAIMER Temperature
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