Why Calibration of instrument is important

The main reasons for calibration are to ensure the reliability of the instrument, that it can be trusted. To determine the accuracy of the instrument and to ensure the readings are consistent with other measurements. It could also void your warranty if your instrument is not calibrated.

What is Calibration ?

Calibration is the activity of checking by comparison with a standard ,the accuracy of a measuring instrument of any type. It may also include adjustment of the instrument to bring it into alignment with the standard.

Purpose of instrument calibration ?

Calibration is the process of comparing the output of an instrument to that of a reference (i.e., known accurate) instrument given the same input. When an instrument is calibrated, the proper output is confirmed by the technician over the range of measurement. Before any adjustments are made, the output is recorded. This is called the as-found calibration. If any adjustments are made, the output is checked again and recorded. This is the as-left calibration. If no adjustments are needed, the as-found values are used.

One benefit of a DP flow meter is that the two major components, which are the primary element and the DP transmitter, can be calibrated or verified independently. A flow system can then be assembled into a complete flow meter with an uncertainty based on the two component calibrations. This capability allows the primary elements and the DP transmitters to be stocked and assembled into calibrated flow meter systems when needed.

Why is Calibration Necessary ?

It is impossible to make perfect hardware that would not need any form of error correction. Even making the hardware good enough to eliminate the need for error correction for most devices would be extremely expensive.

The accuracy of network analysis is greatly influenced by factors external to the network analyzer. Components of the measurement setup, such as interconnecting cables and adapters, introduce variations in magnitude and phase that can mask the actual response of the device under test.

The best balance is to make the hardware as good as practically possible, balancing performance and cost. Calibration is then a very useful tool to improve measurement accuracy.

What is Purpose of Calibration ?

Calibration refers to the act of evaluating and adjusting the precision and accuracy of measurement equipment. Instrument calibration is intended to eliminate or reduce bias in an instrument’s readings over a range for all continuous values.

Precision is the degree to which repeated measurements under unchanged conditions show the same result.
Accuracy is the degree of closeness of measurements of a quantity to its actual true value.

When do Instruments Need to be Calibration ?

Before major critical measurements.
After major critical measurements.
After an event
When observations appear questionable
Per requirements
Indicated by manufacturer

What is Important of Calibration ?

Calibration of a measuring equipment or working standard enables the user to take note of the deviations and errors from the nominal values so that corrections can be made to minimize the errors during measurement.

A well-calibrated instrument provides the confidence to the user as well as the consumer that the service or the product meets the required specifications and ensures the acceptance in international market.

What is Calibration and verification ?

Initial calibration and required maintenance of DP flow instrumentation is necessary to maintain accuracy and reduce instrument error over time. Instrument error can occur as the result of various factors, including sensor drift, environmental changes, electrical supply variations, addition of components to the output loop, primary element wear, or contamination, process changes, and more. Calibration is the process that minimizes these instrument errors. A calibration is performed to ensure that a flow meter is operating within acceptable accuracy requirements. This may require trimming or adjusting the sensor if the transmitter is found to be out of specification, inspecting and cleaning the primary element, and leak checking the impulse piping system. DP primary element calibration must be done in a flow laboratory. In rare cases, an in-situ calibration can be performed, but it may be more costly and difficult to perform. After a calibration is performed, a certificate or report will be issued that confirms the performance of the specific unit. If a primary element has not been calibrated, the performance can be stated using available sufficient statistical evidence for the design type and required tolerances.

Verification is similar to calibration except that no trims or adjustments are performed on a flow meter. It is simply a method that verifies the flow meter output is within the stated accuracy range. It is recommended to perform a verification before any calibration, allowing users to efficiently confirm performance without inducing potential errors involved with a full calibration. demonstrates how verifications should be done first, and only if the unit fails verification should a calibration be performed. Calibration and verification should be performed with precision calibration equipment that has a traceable uncertainty 3-5 times better than the instrument being calibrated. Inadequate calibration equipment, improper use of equipment, or improper calibration procedures can result in the introduction of systematic error to the flow meter measurement. For the DP primary element, geometry verification will ensure that the device is operating within specifications. An example of this is verifying the bore diameter on an orifice plate and confirming that it still has a sharp edge. Verification allows confirmation of the device’s accuracy without risking the introduction of error.