Saturday 15 December 2018

Basic of Calibration

A Calibration has a different understanding of both theoretical as well as practical. Even in a casual chat instead often came out a little short of actual understanding. The calibration is considered exactly the same with the services of a refurbish Cool Pad, where described a grandmother age entered into the black box and then not long after young girls came out beautiful. Well, if this kind of affairs anyway, people flock to sign in so the calibration technician.

Introduction (Basic of Calibration)

In everyday life the calibration operations for over ten years, I also often get that hope is customer want an order it gauge (for calibration services) at a calibration Lab will be like new again. Even once asked why his instrument looks not determined-whether incoming leek, kook out still leek. This reality, which makes my boss ordered to wipe clean-up measurement tool (even washing the cover if removable) after the finished gauge calibrated, so that there is the impression of (tangible) that the measuring instrument into a "beautiful young girl" back.

The way, apart from the bustle of the Lab technician to give socialization to (all so that there is an excuse if the tool measure it cannot adjust), ISO have created official definitions for this calibration to be the standard for the World Metro logy internationally.

According to ISO/IEC Guide 17025:2005 and the International Vocabulary of Metrology (VIM), calibration is an activity that relates the values indicated by a measuring instrument or the value that is represented by a material measure with values the already known level of righteousness (which is related to the quantity being measured).

The Values (Basic of Calibration)

The value that is already known is usually refers to a value of calibrator or standard, which of course must have a higher accuracy than the gauge tests (commonly referred to as the unit under test UUT or). This corresponds to one of the goals is to achieve the traceability calibration measurement or to keep the traceability of this link is not broken.

So straightforward put it this way, for example, I will compare the readings of voltage 10 V of a multi meter with readings from other multi meter has a value of better accuracy, well it can already be said calibration. Of course this also invites questions other questions, such as how the true accuracy of the second multi meter, and how the validity of judgments given.

Assessment Judgement

Who may conduct the assessment judgment and so on, but to simply give a sense of the basic course of the calibration, the above definition is already OK.

But there is one thing that is interesting here, by this definition then legally per-ISO's, it appears that an adjustment (let alone the refurbishment) must not be done. So this law protects a Lab if there is customer that "forcing" Lab to do the adjustment against the tool measure it. For actual Lab also does not present a problem, if there is such customer live just cancelled services.


Which often becomes the question is also what benefits obtained from these calibrations?

Of course many, among the many benefits, the benefits of "basic" is to:

  1. Support quality system applied in the industry. This was the most popular being the driving person or industry want to calibrate his instruments. ISO 9000 requires all related measuring instrument in the production must be guaranteed the quality of its accuracy. And one of the main tools for this is to do a calibration. This requirement in recent years increasingly feels unpopular along with increasingly lax application of ISO 9000. Moreover, at this time many companies competing certificate givers get customer, which eventually gave rise to negative impact also with making loosen the rules so that (for example) by performing a calibration tool 10  only, from 100 measuring instrument should be calibrated, finish the problem. Let alone if the person who is appointed as representatives of auditees have excellent communication ability (a.k.a. clever Basil tongue), making it easy getting this certificate without the tired-tired out charges for calibration. One more thing that often happens customer don't feel the direct benefits (even the technical benefits in the field) of the calibration activities, so that it can be used as an alibi for an excuse not to do the calibration. This alibi and can convince the ISO auditor.

  2. Can find out the correct price with price irregularities indicated measuring instrument. If this is indeed the reason for the technical nature, and the technician who usually feel the real benefits.


Whatever be the element of system calibration process?

  1. Existence of the objects of measurement (Unit Under Test)

  2. The existence of the calibrator (standard)

  3. A existence of the calibration procedure, which refers to the calibration standards, national or international procedures develop by the one who laboratories has been test with the first verification.

  4. The existence of technicians who have been eligible had the technical ability of calibration (preferably certify).

  5. Conditioned environment, either the temperature or the humidity. Even though could not be condition, for example occurs when calibration is perform in the open field. Then environmental factors must be accommodate in the process of measurement and calculation of the uncertainty.

  6. The results of the calibration itself, i.e. quality record in the form of a certificate of calibration. In it record measured value, the correction value, and finally the value of uncertainty. This certificate is not a raw shape, at least should be able to give you information about how healthy customer belonging to gauge which is calibrate. That is, we can add a lot of information that is need, even could have added photos, pictures, special analysis results, in vain TOUR (Test Uncertainty Ratio), was even able to just attach performance report calibrator use in this process.

Note: the TOUR is a comparison between the uncertainties of the characteristics of the instrument is calibrated against uncertainties instruments the calibrator (specification tool can be considered the greatest uncertainty)


how long intervals of calibration done? A year? Or may customer ask for a five-year calibration interval for example, from which is usually a year?

All actually depends on the customer, because after all measuring instrument they become their own responsibility. However, the Lab may only give a recommendation that a tool the calibration interval should be a year, for example. Of course all the scientific basis must exist.

Measuring Instrument

This is all also very depending on the age of the measuring instrument. Its performance, even any the manufacturer who obviously has its own weights. To determine calibration intervals. For the determination of calibration intervals, for electrical testing. Most usually expressed periodically calibrations should be perform. Though in some cases the turning should be taking into account also the conditions of usage. Frequency the usage right down to the question of how to do treatment.

So if there is customer ask for calibration intervals (usually expressed in the term "calibration due date"). It was declare more than a year. Example, the Lab should check first its history, performance, and technical notes. (for example, by looking for a technical note on the Internet or catalogs or other sources). For the Lab afterward can help judgement that interval. However, if the Lab were not able to do so, we recommend emptying the Lab only. The recommendation and all submitted to customer, as this will affect the reliability Lab, too.

ISO Process

In the process, ISO else consider this, there are rules that prohibit arbitrary Lab to give its calibration interval judgement. These are usually sometimes complete Lab to commercial affairs, of course the faster the measuring instrument must be calibrate.  Again it will progressively heighten the chance of getting its economic effects Lab. And this will certainly be potentially injurious customer.

In the determination of calibration intervals, can also be express in calendar time such as one year. Could use time of use for example in 500 hours of use. It Can also use a combination of both, whichever first happens, yes similar to the timing replacement car oil.

There is actually a formula of how to specify the calibration interval. But maybe next time we discussed in the writings of others.

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