What Functions Should You Look for in a Digital Temperature Calibrator?

There are several brands and manufacturers of thermocouple temperature calibrators in the marketplace today. Like most instruments and devices, not all temperature calibrators are created equal. Advanced Energy's TEGAM provides information here based on our 940A and 945A thermocouple temperature calibrators. Below are functions that an operator should expect to be able to use with the thermocouple calibrator that is purchased.

Support for multiple types of thermocouples – choose a model compatible with the thermocouple types that you use. Thermocouple calibrators are generally available in a basic model that supports Types J, K, T, and E thermocouple probes (which are the four most popular thermocouple types) and a higher priced model that will support 14 (or more) thermocouple types. If you are a heat treater or measuring high temperatures, you will need the premium model that supports more TC types to read the Tungsten and Platinum thermocouple types typically used for high-temperature measurements.

Precision Sourcing – simulating a thermocouple output. The thermocouple temperature calibrator should easily and accurately supply (SOURCE) a small, stable voltage that simulates a thermocouple signal. “Easily” is the key word here as this is what you as the user will have to set and adjust every time you use the thermocouple calibrator. “One hand” operation is important for the sourcing function because you are often holding something in you other hand or recording a reading when performing this operation.

Cold Junction Compensation (CJC) – is a key component of any thermocouple measurement. Remember, a thermocouple is a differential device, creating a voltage that is equal to the difference in the temperature between its two ends. One end is your measurement point and the other end is the temperature at the connection to the temperature calibrator. The CJC is also a key component in the overall accuracy of the temperature calibrator. Be sure to note that the calibrator’s accuracy specification includes the CJC. Some manufacturers claim high accuracy but use an external $5000 ice point reference as the CJC for their specifications. This creates an unrealistic accuracy specification that you will never achieve using the instrument.

Dual Displays – being able to see what the calibrator is SOURCING and what a system thermocouple is outputting to the calibrator (READ) at the same time is a must-have feature. Otherwise, you will have to switch between the SOURCE and READ functions (and wait for the reading to settle) to see both temperatures and you can never be sure the output is where you set it at the exact time to compare the two.

Precision Thermometer – a thermocouple temperature calibrator should also be a precision thermometer. The TEGAM 940A and 945A thermocouple temperature calibrator models now have 0.01° resolution so you can easily see the direction of drift or when the system has reached stability.

Statistical Functions

AVG, STDEV (Standard Deviation), Trend, MAX, MIN, RNG can be invaluable tools for understanding your readings.

The AVG function does a mathematical average of the temperature over the time between resets. This function helps interpret real world situations where the temperature will vary slightly due to heating/cooling systems or day/night temperature settings.

STDEV is the standard deviation for readings over a period of time. This helps you understand how large the temperature swings of a system are and helps in tuning or dialing-in a control system.

Trend arrows are a feature that can tell you, at a glance, whether your system temperature is increasing or decreasing. (Rather than watching the display bounce between 0.1-degree increments…) 

The MAX function will capture and hold the maximum reading the unit measures once you start the function. This can be used to check the long-term stability of a system or to assure that nothing went wrong over an unobserved time of test (e.g., overnight).

The MIN function will capture and hold the minimum temperature reading once you start the function. This works in conjunction with the MAX function so you can immediately know the MAX and MIN temperatures that a system produced over a specific length of time.

The RNG (Range) function displays the difference between the MAX and MIN readings captured during your test period.

Please contact us with any questions or comments you may have on our durable temperature calibrators for multiple industries. The 940A and 945A temperature calibrators can be purchased securely on their individual product pages.