News

• 13

  DEC

  Electronic scale weighing accuracy

  The important feature of the electronic scale is that it does not need to measure the weight of the weight when measuring the mass of the measured object, but uses the principle that the electromagnetic force is balanced with the gravity of the measured object to measure. The weighing pan is connected to the coil through the bracket connecting rod, and the coil is placed in the magnetic field. If the weighing object is added to or removed from the weighing pan, the electronic balance will produce an unbalanced state. The position detector detects the transient displacement of the coil in the magnetic steel, and a change is generated by the PID regulator and preamplifier The output, after a series of processing, changes the current flowing through the coil, so that the electromagnetic force also changes and cancels with the measured object so that the coil returns to the original position and reaches a new equilibrium state. This is the principle of the electromagnetic balance automatic compensation circuit of the electronic balance. The change in current shows the mass of the object being weighed by numbers. With the development of modern sensor technology, the electronic balance industry has also developed rapidly, and there are more and more types of electronic balances on the market. For our ordinary consumers, how to buy electronic balances becomes more and more difficult. Large-scale electronic scales We generally call the balance for measuring small objects as the micro-electronic balance. The range of the micro-electronic balance is generally between 3-30g or 0.1-1g. The range of the microelectronic balance is very small, so we should not place excessive objects during use to avoid damage to the balance; in addition, we should also pay attention not to put wet or corrosive substances directly into the weighing pan, because this will cause Corrosion of the weighing pan leads to a large measurement error; at the same time,

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• 13

  DEC

  The first domestic large-scale weighing instrument automatic loading temperature and humidity test device was successfully developed

  A few days ago, the Chinese Academy of Metrological Sciences successfully developed the first large-scale automatic weighing temperature and humidity test device in China, and passed the expert appraisal. The device can automatically realize the weighing performance test of large-scale weighing instruments under temperature and humidity conditions through the robot loading and unloading system without disassembling the weighing instrument. The overall technical indicators are better than foreign existing devices, which greatly improves the capacity of the weighing instrument performance testing system in China. Electronic pricing scales, electronic truck scales, railroad scales, quantitative packaging scales, port scales ... A wide range of weighing instruments are closely related to people's production and life. Whether the quality of weighing instruments is qualified is very important for maintaining market economic order and trade fairness. effect. Weighing performance test including weighing performance test, repeatability test, tare test, etc. is the main means to ensure accurate measurement and qualified quality of the weighing device. It is understood that, in accordance with the relevant national weighing instrument verification regulations, in addition to the normal temperature test, the performance evaluation test of the weighing instrument also needs to be performed under temperature and humidity conditions. In order to complete the test under temperature and humidity conditions, the module method was used in the past, that is, the large scale weighing instrument was dismantled and moved into the temperature and humidity test box, and then the testers analyzed and tested each component separately. However, the module method is not only cumbersome, but the tester entering the temperature and humidity test chamber will affect the reliability of the test results. At the same time, the high and low temperatures of up to 40 ° C

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• 15

  JUN

  Force sensor design process should pay attention to the solution

  inductance For the resistance strain gauge type load cell (hereinafter referred to as "load cell"), the structural shape and related dimensions of the elastomer have a great influence on the performance of the load cell. It can be said that the performance of the load cell mainly depends on the shape and related size of its elastomer. If the elastomer design of the load cell is unreasonable, no matter how high the processing precision of the elastomer and the quality of the attached strain gauge, the load cell is difficult to achieve high force measurement performance. Therefore, in the design process of the load cell, it is important to design the elastomer properly. The design of the elastomer is basically within the scope of the mechanical structure design, but the structure is different from the ordinary mechanical parts and components due to the need of the force measurement performance. In general, ordinary mechanical parts and components only need to meet the strength and stiffness under a sufficiently large safety factor, and the stress distribution on the parts or components under stress conditions is not strictly required. However, for the elastomer, in addition to the mechanical strength and rigidity requirements, it is necessary to ensure the stress (strain) of the strain gauge portion (hereinafter referred to as the "patch portion") attached to the elastomer and the load that the elastic body bears. The force measurement) maintains a strict correspondence; at the same time, in order to impro

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