Browse F.A.Q. Topics
What is the difference between scale and balance?The difference in mechanical balances is in function of its principle of operation. Scales measure the force exerted by an object subject to the force of gravity, while the scales measure the weight of an object by comparing it with a known scale. Just as the scale is used to weigh large and bulky masses, the balance is used to weigh smaller masses of only a few kilos, being usual for example in laboratories. When we talk about scales or electronic scales, the difference is not clearly defined. In general terms, scales are used to weigh large masses, although the precision (d) is smaller. On the other hand, the opposite is true. It is quite common that the scales have a platform at ground level, where it is easy to place the mass to be weighed. In general terms, it is usually accepted that up to 30Kg capacity, the instrument is a balance. For larger capacities, a scale is considered.
What is a bi-range balance?The weighing range of a balance is divided. It starts with a fine range that has more precision (d1). When this fine range is exceeded, the reading automatically moves to the next range (d2) which is usually a lower step (2 x d1). Balances of two ranges can have a defined fine range, or the fine range can be scrolled through the full range. For example, in a model of balance of 2Kg capacity in whose first 300g the sensitivity is 0.01g. When it exceeds 300g, the sensitivity of the balance automatically changes to 0.1g. Now suppose that we put a container of 500g on the plate, tare and then add weight. If the fine range can travel through the entire capacity of the balance the reading will have a sensitivity of 0.01g. Otherwise, it would be 0.1g.
What is a micro balance and a semi-micro balance?A micro balance is an analytical balance with precision d = 0.001 mg. A semi-micro balance is an analytical balance with accuracy d = 0.01 mg.
What is the difference between internal and external calibration?External calibration requires the use of an external standard mass. During an external calibration, the calibration is adjusted with respect to the constants of the external standard mass. Internal calibration does not require an external pattern. With the internal calibration, the calibration constants of the instrument are adjusted with respect to precise references on the same scale.
What is the uncertainty of a balance?From the point of view of metrology, uncertainty is defined as the characteristic associated with the result of a measurement, which defines bidirectional space centered on the value offered by the measuring instrument, within which a certain statistical probability lies with the value Measured. This type of uncertainty is calculated by the calibration, obtaining statistical data from a series of comparisons of the calibrated measuring instrument against a reference standard with known nominal and uncertainty, which provides demonstrable document traceability to internationally accepted measurement standards. The expression of the measure of any magnitude should not be considered complete if it does not include the assessment of uncertainty associated with its measurement process.
What is traceability?Traceability is the property of the result of a measure whereby this result can be related to or refer to the standards or references of the highest level and through them to the fundamental units of the International System (SI) by means of an uninterrupted chain of Comparisons. When the chain is traversed in the opposite direction, that is, from top to bottom, there is talk of dissemination of the unit. Thus there is a pyramidal structure in which at the base are the instruments used in the current measurement operations of a laboratory. Each step or intermediate step of the pyramid is obtained from the one preceding it and gives rise to the next step by means of a calibration operation. At each step are instruments and patterns that in turn act as patterns or references of the following. As each comparison of the chain introduces new causes of error that give rise to new contributions to the uncertainty of the result, which add to the uncertainty with which the value of the starting pattern is known, it is necessary that the uncertainty of the primary patterns is very lower than those required in ordinary applications. This pyramidal grouping is what is called a calibration and validation plan, which will ensure that all equipment and standards have the appropriate traceability to national or international standards.
Why is it important to calibrate?The aging of the components, changes in temperature and the mechanical stress that the equipment supports deteriorates little by little its functions. When this happens, the trials and measures begin to lose confidence and resent both the design and the quality of the product. This reality can not be circumvented, but detected and limited, through the calibration process. The correct calibration of the equipment provides the assurance that the products or services offered meet the required specifications. There are increasing reasons for manufacturers to calibrate their measuring equipment in order to: * Maintain and verify the proper functioning of the equipment * Respond to the requirements established in the quality standards * Ensure the reliability and traceability of the measures. The calibration of an instrument makes it possible to determine its uncertainty, a fundamental value, within a quality system, for the grouping of instruments into metrological categories for later use. The result of a calibration is what is included in the calibration certificate.
What is calibration?Calibration is simply the procedure for comparing what an instrument indicates and what it "should indicate" according to a reference standard with known value.
What is the difference between a verifiable balance and another that is not?Technically they are the same, but the verifiable balances are endowed with small legal details like Protected Software or additional inscriptions.
What is a EC Verification?EC verification is the procedure whereby the manufacturer or his authorized representative established in the Community ensures and declares that the products subject to paragraph 4 comply with the type described in the EC type-examination certificate and meet the requirements of Present Royal Decree applicable to you.
What scales do the EC verification have?In Spain, according to Order of December 22, 1994 determining the conditions of non-automatic weighing instruments (BOE núm. 2nd, 3th january 1995, with error correction in num. 31, 6th february 1995), in Article 3 appended to, EC instruments, which are used for the following purposes, must have EC verification. * Execution of commercial transactions. * Calculation of fees, tariffs, taxes, premiums, fines, remunerations, indemnities and other similar fees. * Application of norms or regulations, as well as conducting judicial experts. * Weighing of patients for reasons of control, diagnosis and medical treatment. * Pharmaceutical preparation of medicines on request, as well as conducting analyzes carried out in medical and pharmaceutical laboratories. * Determination of the price or total amount in the direct sale to the public and the preparation of prepackages. If you want additional information on the verification of scales, or do not know if you need a verifiable balance, you can send it to the Verification Office in your country. In Spain you can go to the Spanish Center of Metrology (www.cem.es)
What is a Calibration Certificate?It is the Documenta that accredits the technical properties of a balance or a control weight as well as the traceability to the national standard.
What is the Declaration of Conformity?This declaration documents that a product complies with the respective EC regulations. In the case of electronic scales always in combination with the EC mark.