Digital multimeters are electronic measuring instruments that perform multiple measurement functions. A digital multimeter usually can measure voltage, resistance, and current, while some models can also perform temperature readings. Each function of a multimeter must be tested to ensure measurement reading accuracy. The only way to determine the validity of a digital multimeter is to perform calibration.
WHY CALIBRATE A DIGITAL MULTIMETER?
Proper functionality of a digital multimeter is essential to ensure accurate measurement readings; therefore, calibration is vital. Without calibration, chances of errors are likely. Over time, environment and physical use of a digital multimeter can cause the instrument to drift out of calibration; therefore, it’s important that frequent calibration is performed. This helps to verify a digital multimeter’s accuracy and performance meets required specifications.
CHOOSING THE RIGHT CALIBRATOR
When calibrating a digital multimeter, it is important to ensure the correct calibrator is being used. The calibrator used should be at least four times better than the specifications of the digital multimeter it is testing. It should also cover the functions of the digital multimeter it is calibration. Digital multimeters usually have at least five functions that have a variety of functions. The calibrator needs to be able to confirm that the digital multimeter is suitable to use in full range.
Most digital multimeter manuals will recommend functions and minimum specifications that are needed to calibrate the digital multimeter properly. The manufacturer of the digital multimeter should also provide the needed test points and pass/fail limits.
SETTING A CALIBRATION INTERVAL
Many digital multimeter’s will have a manufacturer’s recommendation on the appropriate calibration interval. Although following this interval could be beneficial, it is important to note a digital multimeter should also be calibrated in the following scenarios:
If the digital multimeter is new.
If the digital multimeter has experienced any trauma.
If the digital multimeter usage is heavy
Notably, creating a personalized digital multimeter calibration interval is highly recommended. Every digital multimeter is used differently; therefore, a digital multimeter should be scheduled to be calibrated either annually, quarterly or monthly depending on its usage.