Temperature Calibration Analysis

  • By Md. Ali Ashfaq
  • Published in Calibration
  • Sep 26, 2023
  • 5.65 Min
Temperature Calibration Analysis


Definition of Temperature Calibration:

The Temperature Calibration means there will be a Temperature source, Standard equipment, and a Test device that will calibrate. The test device will calibrate with respect to the Standard temperature Equipment. That means the temperature calibrator will induce temperature but with respect to the Standard equipment, the temperature value will be taken.

In calibration grammar, the tested equipment that would be calibrated is called a DUC (Device Under Calibration or DUT (Device Under Test) or UUC (Unit Under Calibration).

Figure 01: Temperature Calibration with oil bath.

A meaningful temperature calibration will be directly traceable to the SI Unit. The calibration certificate will declare the error or correction value along with the uncertainty range. Temperature Calibration is required whether it needs to monitor the temperature with accuracy. So that the end-user has confidence about his temperature equipment. It will ensure the final production quality. Temperature DUC items are typically a thermocouple, resistance temperature detector (RTD), temperature transmitter, temperature switch, thermistor, and temperature gauge.

What things should be taken care of in temperature calibration?

All calibration reference standards and test tools are impacted by environmental factors. The calibration laboratory must keep track of and regulate environmental factors like temperature according to relevant standards, as mandated by ISO 17025:2017. To reduce

its impact on the accuracy of measurement data, we must continuously monitor, regulate, and record the temperature.

The overall accuracy of a measuring device can be impacted by several variables. All equipment is impacted by temperature, which causes measurements to vary or drift over time. For calibration, a lot of instruments require a temperature-controlled environment.

Uncertainty would form for any kind of uncertainty source. This is one of the reasons why calibration is frequently performed in advance during a particular time frame, which is typically once a year. This ensures that the readings are consistently reliable and precise.

Why temperature calibration is important? Is it necessary?

The importance of calibration depends entirely on the application. It does not matter that much if your barbecue machine indicates 202 °C instead of 205 °C but knowing the body temperature of the patients is 39 °C or 41 °C makes a massive difference. These are sensitive examples and there are many different applications with different requirements in terms of measuring accuracy. It should be necessary to know that your measurements are accurate and nullify the inaccuracy in the process. By doing calibration the user is aware of the equipment error type and overall condition of the equipment. One should do the measurement with full confidence in his product. By the temperature calibration, the user can set the tolerance of the product. So, it might not create any disturbance in the process line. By the user using capability the calibration interval would be set.

Users can feel confident and at ease about the outcomes that are created, monitored, and recorded with the help of regular equipment calibration.

In industries like food and beverage, meteorology, automotive, aerospace, laboratory, research, chemical processing, healthcare, and manufacturing, temperature calibration is necessary. Temperature calibration is performed in these industries in various stages of a system or instrument's operation.

Figure 02: Visibility of Sensor Measurement Error

What are the methods of Temperature calibration?

Figure 03: Temperature Calibration Method with Dry-block

Temperature Calibration is done in two ways,

  1. a) Direct Method
  2. b) Indirect Method

  3. a) Direct Method: This method takes place in the digital temperature meter or related types of measures that can produce and measure electrical signals for temperature testing. The Process is the DUC takes signals from the Standard calibrator that it can produce.

  4. b) Indirect Method: In this method, a temperature sensor or instrument is calibrated by comparing its output to a Standard sensor or Standard instrument that has higher precision and accuracy. A calibrator is there to induce temperature, and DUC and the Standard temperature instrument will take the reading. To show how much the calibrated temperature sensor deviates from the Standard sensor that will be recorded.

After both processes, the analysis report which means a calibration report would be generated.                                                     

Which are Temperature calibration equipment?

The following are common devices that are frequently referred to as temperature calibrators:

  • Standard Thermometer
  • Dry block calibrator
  • Temperature oil bath
  • Temperature heat source
  • Temperature simulator
  • Temperature indicator
  • Thermometer Calibrator
  • Infrared calibrator

What is the Pattern that is been followed in temperature calibration?

All temperature calibrators produce the following three outcomes,

  1. Source temperature
  2. Temperature reading
  3. Temperature report

Source temperature:

Simulating temperature and producing physical heat are two popular methods.

  • Simulated temperature: Simulated temperature calibrators are typically small, portable devices with internal electronic circuits that provide varying degrees of voltage or resistance. The simulator gives the user an option to select the type of sensor that can replicate as well as the operating temperature.
  • Physical Temperature: Temperature calibrators that produce physical heat include temperature dry blocks, temperature oil baths, infrared radiation calibrators, temperature chambers, furnaces, and temperature calibration baths. These calibrators frequently have sensors built in that measure and display the calibrator's temperature.

Figure 04: Temperature D.U.T calibration in comparison method

Temperature reading:

Temperature calibrators read and report temperatures using a few standard methods. One typical method is having a measurement input on the equipment that produces the temperature.

  • The temperature calibrator display shows its temperature and the temperature of the
  • Another typical technique is inserting a sensor into the calibrator while keeping the sensor attached to the reader, transmitter, or display that measures the sensor. Then, the display temperature is contrasted with the calibrator temperature.

Figure 05: Temperature reading parameter

Temperature Report:

A Temperature calibration report is a document that describes the full process of calibration. The calibration report contains information about the procedures and standards used, the parameters examined, the actual measurement findings, the error/correction value, and the level of uncertainty. It also contains the essential components of a calibration certificate. Some temperature calibrators come with an interface that enables the user to connect a digital reference thermometer system, which measures the temperature calibrator more precisely and can automatically communicate with the calibrator, to establish temperature points. Also, it can produce a certificate. This allows for greater precision and simpler use.

Why does One need to do the temperature calibration and the outcome?

In the manufacturing industry, equipment precision and instrument accuracy play a large role in the overall turnover of the organization. The organization needs to get full confidence before any type of production. The accuracy of high-quality instruments is typically expressed as a percentage of the complete measuring range, specifically in the case of an analog thermometer. The thermometer will be accurate to 1 degree Celsius if the complete measuring range is 0°C to 100 °C and the precision is Class 1.0. Accuracy on the complete scale is another name for this precision. Thus, if the object being measured is exactly 50 °C, this particular thermometer should display a reading between 49°C and 51 °C. The thermometer is regarded as incorrect if the reading is outside of this range. This is clarified before doing any type of production customer gets cost-savings and safety for a proper calibration.


Measuring should only be done when the results are reliable. The measuring of temperature is no different. To accurately measure temperature, you must be able to rely on the results of your thermometer or the electrical output of your thermocouple. Temperature calibration is the accurate comparison of a piece of test equipment (a data logger, sensor, or thermometer).

This Blog's goals, which were to measure and analyze the differences between temperature monitoring instruments calibration, were achieved. By comparing temperature variation with the actual signal, the estimated temperature, and the initial temperature, the devices' accuracy may be evaluated.

FAQ (Frequently Asked Question)

What is temperature calibration?

Answer: Temperature calibration is typically compared between a master temperature device and temperature sensors means to known levels of uncertainty or accuracy that are compared to temperature readings from a temperature measuring device. Such as a thermometer or transmitter, of unknown value compared with a known value.

Why is temperature calibration being important?

Answer: Temperature plays a crucial role in medical care (both humans and animals), food, beverages, and agriculture. Temperature calibration also frequently affects our general health in several ways. In facilities used for medical cold storage, maintaining optimum temperatures is crucial.

Why is temperature measure important?

Answer: It is possible to identify disease by taking our body temperature. Additionally, it can keep track of how well the treatment is progressing.

Which equipment is used for temperature calibration?

Answer: Most commonly used to calibrate temperature measurement devices, such as thermocouples, RTDs (Resistance Temperature Detectors), and temperature transmitters.

Which sensors are used to measure temperature?

Answer: Thermocouples, RTDs, thermistors, and semiconductors are mainly temperature sensors that are in temperature calibration.

What are the different types of temperature calibrators?

Answer: Most type of temperature calibrators is simulators and physical temperature sources.

What are the factors needed for a temperature calibrator?

Answer: All temperature calibrator needs a method for obtaining, reading, and reporting the temperature.