Omega CL24, CL25, CL27, CL23A, CL26 manual Resistance Calibration, Test Equipment Required

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B. RESISTANCE CALIBRATION

NOTE: Thermocouple and resistance calibrations are indepen- dent. However, potentiometer P1 is used in both thermocouple and resistance calibrations to set EEPROM constants. Follow cal- ibration 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 cal- ibration 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.

NOTES: 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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Contents
User’sGuide Omega.comTM Table of Contents Common Specifications General InformationTemperature Coefficient Page Model CL24 Unique SpecificationsModel CL23A/CL23EC Model CL25/CL25ECFeatures Manual AddendaModel CL27/CL27EC Safety Information Safety PrecautionsUnpacking Your Unit Page Battery INSTALLATION/REPLACEMENT Battery InstallationMemory Backup Operation with Rechargeable BatteryOperating Instructions Diagnostics and Error MessagesProblem Likely Cause Initial Turn onKeypad Meter Mode Operation Thermocouples Set-Up OPRMeter Mode Operation RTD, Thermistor & Ohms Set-Up HoldData Logging and Recall To Save Readings To Recall ReadingsTo Erase Data Locations Meter Mode Calibrator Mode Operation Thermocouples Set-UpCalibrator Mode Operation RTD, Thermistor & Ohms Set-Up CHANGE/ENTER, 2, 1, 2, 0, CHANGE/ENTERWire Resistance Simulation Storage and Recall of Calibrator Settings To Store OutputsTo Erase Set-Up Locations Calibrator Mode To Recall OutputsStep Function Ramp Function CL25 and CL27Thermocouple Calibration Test Equipment Required Service InformationCalibration Procedures Ambient ConditionsPage Calibration Adjustments Calibrator-Mode Zero & Gain Adjustments Sensor Meter-Mode Zero & Gain Adjustments Sensor StepInput Adjust Reading Output Adjust ReadingCalibration Setup, Copper Mode Resistance Calibration Test Equipment RequiredResistance Calibration Setup RTD-100 390.26Ω Calibration of Meter-Mode Resistance Functions Output Input Adjust Verify ReadingInput Adjust Verify Reading RTD-Thermistor Sensor Unit StepCalibration Verification Model Software Revision Equipment RequiredPage Page Alloy Mode Verification Procedure for Thermocouple Functions Page Mechanical Parts Diagram Calibration Procedures Page Page Page USAWARRANTY/DISCLAIMER Temperature