Calibration and calibration services
Calibration in measurement technology and metrology is the process of comparing the measurement results that a device that is under test can provide with those of a known-accurate calibration standard. A device that generates the quantity that you want to measure, such as a voltage generator, sound generator, or physical artifact like a meter ruler, could serve as such a standard. All of these options have an established accuracy level.
One of the following outcomes from the comparison is possible:
- The device which is under test should not give any substantial error
- You can find a significant number of errors, but you don’t need to adjust any of it
- You can find a significant error, and you have to fix it to adjust the error to a manageable level.
What is temperature calibration?
The term temperature gives the idea that temperature calibration is calibrating temperature-related devices. By comparison, calibrating a thermometer is the easiest and most popular method. Look at what the thermometer reads after placing it into a substance whose exact temperature you know (such as a cup filled with ice and water). The thermometer should read somewhere around 0 °C, or 32 °F, in the case of the cup. The thermometer then needs adjustments to display the proper temperature. Although it may sound rough, you can use the same principle to calibrate extremely precise instruments!
Fixed point calibration is a type of highly accurate calibration. You need to produce a precise melting, freezing, or triple point of a particular substance, such as zinc, water, or argon. The temperature indicator or thermometer provides the measurements. And the measurements need evaluation in great detail because we are aware of precisely what these points should be in accordance with the ITS-90.
Why temperature calibration is necessary?
The application determines how vital calibration is. For us, at least, it doesn’t really matter whether your barbeque reads 202 degrees instead of 205., yet it makes a huge difference to know if a patient’s fever is 39 C or 41 C! These are extremes, and there are several applications with various measuring accuracy needs. Sometimes it may be important to know that your measurements are precise and you can accept minor errors.
Meaningful time to calibrate
You can determine the most meaningful time to calibrate your instruments by specific indications. The circumstances and the installation procedures will determine this. You might perform a test akin to the cup of ice and water test and determine whether your instrument is accurate if you happen to notice a weird reading. The existence of standards for accuracy criteria is far more typical. This frequently happens because already-made standards have some documentations where every process needs to operate within a particular range of precision. Uncertainty would result from a wrong temperature reading! This is another reason why calibration is frequently performed in advance following a predetermined period, which is typically once a year. This guarantees that the readings are consistently precise and dependable.
Accuracy indication
Percent (%) of the complete measuring range typically expresses the accuracy of high-quality instruments, specifically in the case of an analog thermometer. The thermometer will be accurate to 1 degree Celsius if the complete measuring range is 0° 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 that we are measuring is exactly 50°C, this particular thermometer should display a reading between 49 and 51°C. We regard the thermometer as incorrect if the reading is outside of this range. (This also explains why picking the proper temperature range is crucial, as using the same thermometer to measure a temperature between 0 and 5°C can result in a 20% error from the actual temperature!)
For resistance thermometers, a class letter denotes the accuracy. The most popular classes are Class AA, Class A, and Class B. The least accurate is Class B, while the most accurate is Class AA. The IEC 60751 norm provides a global definition of these classes.
When an instrument has accuracy Class B, it can vary by up to 0.30 + 0.0050 | t | (°C), where t is the temperature’s true, absolute value. Because of the thorough the procedure of accuracy establishment, authorizers permit the instrument to stray more degrees as the range increases. The permissible deviation is the same for positive and negative measuring ranges.
Simple example
Let’s look at a simple example. For a type K thermocouple, the formula for Class 1 accuracy is (1.5 or 0.0050 | t |) °C, where one can use the higher value. Keep in mind that the initial value is substantially higher than with the resistance thermometers and that “or” has replaced the plus sign in the formula. Additionally, if you use the bigger value, there is a limit where the accuracy remains constant at 1.5°C before changing to 0.5% of the actual temperature. That would be at 300°C for this class (0.0050 x 300 = 1.5).
In this article, we address the four most frequent questions we receive concerning temperature calibration; however, in the blog that follows, we go into greater detail about the calibration process and provide an example.
Ask about our services
We have been certified by BAB & NABL as an ISO/IEC 17025-approved calibration laboratory. Additionally, we produce and sell Instrument Test & Calibration Benches and Service Field Calibration Equipment. Besides electrical calibration, we also provide Electronic Calibration, Mechanical Calibration, Dimensional Calibration, Temperature Calibration, Moistness Calibration in Humidity Chamber, Weight/Vacuum Calibration, Power/Torque Calibration, Surface Thickness Calibration, Equalizations/Scales Calibration, Hardness Testers Calibration, Autoclaves Calibration.
Please leave a comment below or give us a call if you have any questions about electrical calibration. One of our engineers will be happy to assist you.