Where measurements are important to your business calibration is just as important. The main reason to calibrate test instruments is to ensure that they remain reliable and trustworthy. Calibrating your test equipment allows the user to have full confidence in the results that they produce and subsequently control.
What is Calibration?
Calibration is the process of comparing a measurement from your test instrument with a known measurement (the standard) from another piece of reference equipment and adjusting the output to agree with the value of the applied standard.
The reference equipment should be calibrated to a known set of parameters, be directly traceable to national and international standards and have been calibrated in accordance with Measurement Management Systems to ISO 10012:2003. This is the ISO standard that specifies generic requirements and provides guidance for the management of measurement processes and metrological confirmation of measuring equipment used to support and demonstrate compliance with metrological requirements.
Calibration of your test instrument has two objectives:
- To check the accuracy of the instrument
- To ensure test instruments give reliable results when used in the field
How do Test Instruments lose accuracy?
The longer an instrument is in operation, the more accuracy can degrade and the more frequent errors can occur. These errors are typically caused by normal wear and tear. However, there are also other factors that can influence accuracy.
By calibrating your test instruments, measurement errors can be recorded. A measurement error is the difference between a measured value of quantity and its true value.
If the deviations become so great that they are no longer within the permissible range, then quality can no longer be assured and the instrument will need to be adjusted. The test instrument must be reconfigured so that measurement errors can be reduced and deviations from the set point value remain within the device specifications.
Why is Calibration so Important?
The aim of calibration is to minimise measurement errors or uncertainty by ensuring the accuracy of a test instrument. Calibrating your test instruments is vital as:
- Calibration calculates and controls measurement errors or uncertainties within the measurement process to a specific accuracy range
- Maintaining calibration of test equipment is crucial in order to be confident in the results being measured
- Failure to calibrate or improper calibration may be the cause of injury or unforeseen downtime
- The cost of calibrating your instrument properly can be miniscule in comparison to the cost of damages caused by using an instrument that is not functioning properly
- In some cases, where your test instrument has not been calibrated, your warranty may be considered void
How often should I calibrate my test instruments?
For the majority of industries, calibration should be carried out annually. However, calibration may also be carried out according to the recommendation of the manufacturer, if test results start to fluctuate or after an incident has occurred such as a mechanical or electrical shock for example.
An assessment to determine frequency of calibration can be carried out using the following criteria:
- Manufacturers recommended frequency where available
- Type of instruments (eg. Multimeters usually 1 year, Weights 6 year interval)
- Use of instrument (eg. Environment and frequency of use)
Calibration should always be carried out by a reputable calibration laboratory to ensure that measurement errors are within the acceptable range. Most calibration laboratories will supply a calibration certificate as proof of quality standards, but if not, you should make sure to request one.
The certificate should have as found results if no adjustment was made, if adjustment was made certificate should show before and after results.
The Calibration Process
- Before commencing calibration, test instruments will be examined for any visual signs of damage
- The test instrument will then be hooked up to calibration equipment
- For each of the tester’s functional settings, a series of values will be applied going from the lowest point to the highest point in the measuring range
- Specialised computer software is used to compare the variation in the supplied and displayed values against acceptable tolerances
- A pass or fail result will be calculated. Should the instrument be given a fail result, it will be need to be adjusted back into specification in accordance with the manufacturer’s procedures and tolerances
- Once a pass result has been achieved for all readings and the instrument meets the criteria set out in the manufacturer’s specification, a calibration certificate will be issued and the instrument will be returned to the customer
Where can I get my Test Instruments Calibrated?
Powerpoint Engineering are specialists in calibration services and repair. At our state-of-the-art High Voltage Test Bay and Laboratory in Portlaoise, we offer solutions for all makes and models of electrical test and measurement equipment. This equipment includes Temperature Equipment, Electrical Instruments, Pressure Equipment, Substation / High Voltage, Torque Equipment, PAT Tester, Dimensional and Gas Detection Equipment.
We are 100% committed to getting your equipment correctly calibrated and returned to you so that you have as little downtime as possible. With a nationwide delivery service and typical turnaround time of 5 days, we pride ourselves in providing a fast, reliable and value-for-money service.
We have been assessed by the National Standards Authority of Ireland (NSAI), and are deemed to comply with the provisions of Measurement Management Systems to ISO 10012:2003. We guarantee calibration management traceability for all our lab certificates, which adhere to Irish, European and Global standards.
This post was first published on www.calibrationlab.ie