TC621 Pocket Thermocouple Calibrator


The Wahl TC621 is a pocket size thermocouple calibrator, designed to simplify the maintenance and commissioning of of temperature transmitters and probes.  This model can measure or generate 16 different types of thermocouple temperatures and voltage at an accuracy of 0.02%.

With IP54 protection, these portable units are suitable for onsite use, even in demanding environmental conditions.  The graphical interface makes reading easier, and allows for viewing of graphical or test formats.  Memory can hold 10,000 values.  Advanced functionalities include square root, steps, synthesizer, and statistical functions.   Powered by four alkaline AA sized batteries.

Values can be displayed in °C, °F, mV, and Ω.  Unit features a low temperature coefficient: 10 ppm /°C for thermocouples.

Compatible with thermocouple types K, T, J, E, R, S, B, U, L, C, N, Platine, Mo, NiMo/NiCo.

View data sheet for complete specs.



0.02% of Reading

Temperature Coefficient

As low as 10 ppm /°C for thermocouples and 7 ppm/°C for resistance


5 Languages: English, French, Spanish, German, and Italian


Graphical LCD with adjustable contrast and backlight

Display Resolution

Three user selectable resolutions, up to 3 decimal places: High, Middle, or Low resolution

Date and Time

Continuously Displayed


Maximum, Average, and Minimum are displayed. Reset function allows re-calculating of values.


Freezes the display


Filter can be applied to avoid fluctuation of values

Delayed Start

Select a delayed start when simulating steps or ramps

Ingress Protection

IP54 according to EN60529


Holds 10,000 values

Values Displayed

°C, °F, mV, and Ω


Ramps, preprogrammed steps, and synthesizer values


In measurement and simulation modes. Allows sensors to be corrected after a calibration. Performed with up to 10 segments in order to fit with the real calibrated value.


6.18 in x 3.35 in x 1.77 in (157 mm x 85 mm x 45 mm)


10.8 ounces


Four AA batteries (1.5 V)


USB Port

Reference Range

23°C ±5°C (RH: 45 to 75% w/o condensing)

Operating Reference Range

-10 to 50°C (RH: 20 to 80% w/o condensing)

Limit Operating Range

-15°C to +55°C (RH: 10 to 80% w/o condensing) (70% at 55°C)

Storage Temperature Limits

-30°C to +60°C

Rated Voltage

60 V

Included Accessories

Unit comes with four AA batteries, protective boot, and wrist strap.

Compatible Thermocouple Types

K, T, J, E, R, S, B, U, L, C, N, Platine, Mo, NiMo/NiCo