Calibration An introduction to electronic calibration
Critical applications that require carefully maintained control and precise, accurate measurements must use calibrated power electronics as components can drift over time due to a variety of factors.
Most instrumentation-grade power electronic devices contain both source and measurement functions. A high-performance power supply will include a voltage and current source, voltmeter, and ammeter. In contrast, a battery tester contains a charger (source), a discharger (load), a voltmeter for the measurement of battery voltage, and an ammeter for the measurement of current.
These types of power electronic devices are used in critical applications where it is important to carefully maintain control, for example, to ensure that a charger does not overcharge a battery and cause it to overheat or that the power supply does not damage a sensitive component. They are also used when an accurate measurement is needed, such as to report on real-time current draw as it operates in various states and environments.
Why calibration is needed
Where careful control and accurate measurement are needed, power electronics must be calibrated. Despite power electronics leaving the factory floor in perfect calibration, it is important to carry out periodic recalibration because components can drift over time due to many factors, including physical shock and heat cycling.
The aim of periodic calibration is to ensure that a power instrument returns to its optimal calibrated state before it drifts out of calibration, where it has the potential to damage systems.
Once upon a time, calibration was a mechanical process that required the adjustment of potentiometers. Today, it is a straightforward electronic process—there is no need to open up a device or system and start tinkering with internal components. In most cases, calibration can be achieved without even moving the instrument in question. This saves a lot of time, labor, and money in specific environments, such as when equipment is built into a rack.
Factors to consider
If there is a chance that a vital piece of equipment may produce incorrect output, it must be calibrated. How often this will be required depends on several different factors, including:
- The age of the equipment
- Recommendations from the last calibration certificate
- Changes in the environment
- Transporting the equipment
- Manufacturer’s recommendations
- Maintenance and service history
- The tendency of the device to wear and produce inaccurate results from use or storage
- Frequency and severity of use
These elements help to determine how often calibration is required. Calibration that is not performed often enough could cause equipment to return inaccurate measurements outside an acceptable range of error. Regular calibrating helps to avoid this, giving you the confidence that your equipment is operating as it should and without error.
Electronic power calibration has multiple other benefits, too. These include the correction of manufacturing tolerances, mitigating end-user concerns, improving equipment reliability, decreasing test times while improving product delivery times, and allowing for the use of lower-cost components that feature higher manufacturing tolerances.
To meet proper national and/or international standards, a professional calibration technician is often required to carry out the work. This varies between locations, however.