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Handheld Temperature Calibrator for all Thermocouple Types

Item# CL23A

Handheld Temperature Calibrator for all Thermocouple Types CL23A CL23A
  • The CL23/24/25/26/27 Models has been discontinued. Please see the CL940A/ CL945A/ CL543B as a possible alternative or contact Sales

  • NIST Traceable Certificate of Calibration
  • Simulates and Measures Thermocouples, RTDs, Thermistors and Ohms
  • 0.1°F/0.1°C Resolution
  • 10 Memory Locations for Saving Meter Readings and/or Calibrator Outputs
  • Step Calibrator, Meter Hold, Thermometer Functions
  • Ramp Function (Models CL25 and CL27)
  • Review PDF File (Link Below) for Full Specifications & Features

The CL23/24/25/26/27 Models has been discontinued. Please see the CL940A/ CL945A/ CL543B as a possible alternative or contact Sales

The OMEGA CL20 series calibrator/ thermometers simulate, measure and record RTD, ohm, thermocouple and thermistor signals–all in one meter. They outperform the competition in the lab and on the factory floor with 0.3°C (0.5°F) accuracy and in ambient temperatures from 18 to 28°C (64 to 82°F).

This powerful handheld meter allows the user to calibrate in the field as well as in the lab and offers many additional functions that translate into costeffectiveness, increased productivity and long-lasting versatility and reliability.

The 5-digit LCD display indicates all active functions and allows users to have 0.1° resolution in both Celsius and Fahrenheit. This convenient display takes the guesswork out of which sensor has been selected, displaying °C or °F and operating mode.

Programming a CL20 series calibrator is a snap. The keypad allows direct entry of calibrator setpoints. Setpoints can also be entered from an outside source by inputting temperatures or voltages through the thermometer mode. There are no reprogramming hassles. The program won’t be lost when the meter is shut off. All values are retained and can be retrieved for fast repeat use.

These calibrators feature 10 memory locations that can instantly recall any programmed value, and the step function lets the user run through the test points at the push of a button. This efficient feature saves time by allowing the user to simply enter the output value and calibrate.

The ramp function of Models CL25 and CL27 makes calibrating switch and alarm setpoints quick and easy. By entering the upper limit, lower limit and step size, the meter automatically ramps between the limits. There is also a manual ramp function.

No matter what thermocouple type is used, one of these meters can handle it. Features to choose from include 100 ohm and 1000 ohm RTD and 2252 ohm thermistor capabilities.

Need to comply with ISO-9000 reporting specifications? These meters can help! All conform to the temperature/voltage tables of the National Institute of Standards and Technology (N.I.S.T.). OMEGA provides a free NIST Traceable Certificate of Calibration for your records. Since ISO-9000 requires that calibration be done at the equipment site, these meters are a perfect choice. With 0.3°C (0.5F°) accuracy in an ambient temperature range of 18 to 28°C (64 to 82°F), you’re not confined to the lab. Take it everywhere. The ABS plastic case protects it from dust and dirt.


Display: 5-digit LCD custom indicators for calibration type, units hold, recall, store, operating mode, bal, loaded memory locations (up to 10) Keypad: Momentary switches with tactile feedback, select power, thermocouple type, units, resolution, hold, store/recall, stop/clear, operating mode
Configuration Retention: selected operating mode, thermocouple type, units, resolution and memory contents retained on power off
Diagnostics: low battery, open input, invalid keypad entry, out of range, internal hardware fault
Accuracy: see ordering matrix for details
Ambient Temperature: 0 to 50°C (32 to 122°F), 0 to 90% RH
Reading Rate: 1 per second
Input Current: 50 nA typical(meter mode)
Output Load: 100 ohms, min. (calibrator mode)
Max. Common Mode Voltage: 42 V peak to earth ground
Power: 9 Vdc battery, alkaline, included
Battery Life: 16 hrs alkaline
Dimensions: 178 H x 74 W x 28 mm D (7.0 x 2.9 x 1.1")
Weight: 340 g (12 oz)
  CL20 Series Temperature Measurement and Calibration Range
Range Resolution
K 200 to 1371°C -328 to 2502°F 0.1°
J -210 to 760°C -346 to 1400°F 0.1°
T -200 to 399°C -328 to 752°F 0.1°
E -230 to 999°C -382 to 1832°F 0.1°
N 200 to 1299°C -328 to 2372°F 0.1°
B 499 to 1815°C 932 to 3308°F 0.1°
R 0 to 1768°C 32 to 3214°F 0.1°
S 0 to 1768°C 32 to 3214°F 0.1°
G 299 to 2315°C 572 to 4201°F 0.1°
C 0 to 2315°C 32 to 4201°F 0.1°
D 0 to 2315°C 32 to 4201°F 0.1°
RTD -200 to 849°C -328 to 1562°F 0.1°
Series 400
-40 to 150°C -40 to 302°F 0.1°

CL26 and CL27 Resistance Measurement
and Calibration Outputs
Ohms Range Resolution Models
0-100? 0.01? CL26 & CL27
0-1000? 0.1? CL27
0-100,000? 1.0? CL26

TC Types Platinum
Thermistor Resistance
0 to:
Accuracy Calibrator
& Thermometer
CL23A K, J, T --- --- --- --- ±0.3°C from -46 to 677°C
0.04% over 677°C
±0.5°C under -46°C
CL24 K, J, T, E --- --- --- --- 0.04% over 677°C
±0.5°C under -46°C
CL25 K,J,T,E,N,R,S,B,G,C,D --- --- --- --- ±0.3°C full scale K,J,T,E,N
0.8°C full scale B,R,S,G,C,D
CL26 K, J, T ,E 100? 400 Series
100 k?
±0.3°C from -46 to 677°C
0.04% over 677°C
±0.5°C under -46°C
?s: 0.04% of range
±0.3°C RTD & thermistor
CL27 K,J,T,E,N,R,S,B,G,C,D 100?
--- 1k?
±0.3°C full scale K,J,T,E,N
0.8°C full scale B,R,S,G,C,D
?s: 0.02% of range
0.1°C full scale RTD
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Rated 4 out of 5 by from Field Work Horse My company uses the CL23A to check temperature calibrations. The unit is a real work horse for the field engineers. My only concern is the battery and its connections. The 9V battery is not as easy to find any longer and the terminals can be affected when the unit gets handled rough in check luggage.
Date published: 2016-06-30
Rated 5 out of 5 by from Reliability I had a CL23 for over 20 years in perfect conditions with all its features working but it was stolen from my vehicle. When searching for a replacement found that the same model was still in the market and ordered it without a doubt.
Date published: 2018-04-13
Rated 1 out of 5 by from very fast delivery time and excellent, compact pac We use this instrument to measure temperatures in coal mine blast holes. The coal being mined is on fire and temperatures often exceed 400 degrees. The instrument stands up to the terrible outdoor conditions in which we work and is accurate and reliable.
Date published: 2016-12-10
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