Calibration

Nunes Instruments provides valid and accurate measurements using updated standards.

Calibration! What is it ?

A set of operations, performed in accordance with a definite procedure, that compares the measurements performed by an instrument to those made by a more accurate instrument or a standard for the purpose of detecting and reporting, or by adjustment, errors met in the instrument tested.

Purpose of Calibration

To ensure readings from an instrument are consistent with other instruments and to determine the accuracy of the instrument i.e. that it can be trusted for its observed/displayed measured value.

The value of calibration for industry

  • To ensure that products are manufactured to specifications.
  • To demonstrate that the industry operates a quality system and technically competent and are able to generate technically valid results.
  • To increase quality & value of product.
  • The calibrated measuring instruments (working standards) have the assurance of an unbroken chain of national/international measuring standards.

What is Traceability ?

Property of the result of a measurement or related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties.

Why measurements must be Traceable ?

  • Traceable measurements ensure the uniformity of manufactured goods and industrial processes.
  • To support equity in trade as well as compliance to regulatory laws & standards.
  • Essential to the development of technology.
  • To provide traceable calibration of test and measurement equipment is an ISO-9000 requirement(Purpose: With an eye to provide safety and fitness for use) to ensure that the products manufactured in one country will be acceptable in another on the basis of agreed to measurement standards, methods & practices)
  • Provides users with assurance of the confidentiality, validity and accuracy of the data provided while testing.

Uncertainty- How accurate are your measurements ?

  • It is a measure of the quality of a measurement & provides the means to assess & minimize the risks and possible consequences of poor decision.
  • (A measurement with a stated uncertainty can be compared to others)
  • (Measurements are traceable when they can be related to recognised measurement system through an unbroken chain of comparisons each with stated uncertainties.)

Calibration Interval-Validity Period.

  • Validation is usually nominal maximum period between two successive calibrations. The validity period is generally considered to be maximum appropriate, provided
  • The equipment is of good quality and is of proven adequate stability.
  • If any suspicion or indication of overloading or mishandling arises, the equipment will be checked immediately and thereafter at frequent intervals until it can be shown that stability has not been impaired.
  • The extension of validity period is based on factors such as history of stability, frequency of use, accuracy required, ability of staff to perform regular checks and successful participation in proficiency testing programs. It is the responsibility of the testing authority to provide evidence that its calibration system ensures that confidence in the equipment can be maintained.
  • Adequate records of the test data must be maintained over a period of time to draw support for extension of validity period.

Calibration Measurement! How ?

  • Verifying the performance of the test Instruments which involves applying a standard value to the Instruments and observing how it behaves.
  • Adjust the response of the Instruments, wherever possible(After verifying response, reset, adjust/correct the Instruments via internal control which in normal course is not accessible)
  • Obtain correction factor for the test Instruments.(Accordingly correction factors/calibration constants are calculated & incorporated in measurements)

A standard preventative maintenance service on all instruments by Nunes Instruments Technical Advantages includes:

  • Pre-service calibration checks are taken
  • The equipment is checked internally for any damage, loose electrical connections or foreign material. The cover/s are refitted after all practical foreign material is removed.
  • The instrument is then checked externally for damage, inoperative switches, frozen leveling feet or poorly adjusted tare bars. Any old and excess stickers are removed and the housing is cleaned as necessary Corner load, linearity and calibration errors are corrected to obtain optimum performance
  • A service sticker is attached to the Instruments which includes the Service and Calibration Report numbers, date the instrument was serviced and when the next preventative maintenance service is recommended
  • A Calibration Report is supplied

Related Information: