Classified repair and maintenance of the hottest e

  • Detail

Classification, repair and maintenance of electronic balance

classification, repair and maintenance of electronic balance I. electronic balance and its classification

people call the balance called object gravity by electromagnetic force as electronic balance. It is characterized by accurate weighing, fast and clear display, automatic detection system, simple automatic calibration device, overload protection and other devices. According to the accuracy of electronic balance, it can be divided into the following categories:

1. Ultra micro electronic balance the maximum weighing of ultra micro electronic balance is 2 to 5g, and its scale division value is less than (maximum) weighing. For example, METTLER umt2 electronic balance belongs to ultra micro electronic balance

2. Microbalance the weighing of microbalance is generally between 3 and 50g, and its division value is less than (maximum) weighing, such as Mettler's at21 electronic balance and sartoruis' S4 electronic balance

3. Semi microbalance the weighing of semi microbalance is generally 20 to 100g, and its division value is less than (maximum) weighing, such as Mettler's ae50 electronic balance and sartoruis' m25d electronic balance

4. Constant electronic balance this kind of ordinary balance is made of excellent alloy structural steel. The maximum weight is generally 100 to 200g, and its division value is less than (maximum) weight. For example, METTLER's ae200 electronic balance and sartoruis's a120s and a200s electronic balance belong to constant electronic balance

5. Analytical balance in fact, electronic analytical balance is the general name of constant balance, semi microbalance, microbalance and ultra microbalance

6. Precision electronic balance this kind of electronic balance is a general designation of electronic balance with accuracy level of grade II

II. Precautions for purchase and use

1. (1) how to select an electronic balance? The absolute accuracy (division value E) of the electronic balance should be considered to see whether it meets the accuracy requirements of weighing. If you choose a balance with 0.1mg accuracy or a balance with 0.01mg accuracy, do not generally say that you should not use a balance with 1/10000 or 1/100000 accuracy, because some foreign manufacturers use relative accuracy to measure the balance, otherwise the balance you buy cannot meet the needs of users. For example, in the actual work, a Mettler electronic balance with an actual scale division value D of 1mg, a calibration scale division value E of 10mg and a maximum weighing of 200g is used to weigh 7Mg objects, which cannot obtain accurate results: it is stipulated in the JJG non automatic leveling trial verification regulation that the maximum allowable error is the same order of magnitude as the calibration scale division value "e", and the maximum allowable error of this balance is 1E, Obviously, 7Mg objects cannot be weighed; This kind of balance is not the best choice for weighing 15mg objects, because the relative error of its test results will be very large, so a higher level balance should be selected. Some manufacturers have specified the minimum weighing value when leaving the factory. Therefore, we must consider the accuracy level when purchasing and using electronic balance

(2) for the requirements of symmetrical quantity range, in addition to its accuracy, the electronic balance shall be selected to see whether the maximum weighing meets the requirements of measuring range. Usually, the maximum load plus a little safety factor can be taken, that is, the common load can be relaxed, not the larger the better

2. About the calibration of electronic balance (the manual must be read carefully before use). During the verification (test), we found that the error of the balance during the first measurement test was large. The reason is that a considerable number of instruments were not calibrated within a long time interval, and it is considered that the balance can be weighed directly when it shows zero. (it should be pointed out that when the electronic balance is turned on, the zero point is displayed, which does not mean that the accuracy of the weighing data of the balance meets the test standard, but only that the stability of the zero position of the balance is qualified. Because it is necessary to comprehensively consider the compliance of other technical indicators to measure whether a balance is qualified or not). Due to long storage time, moving position, environmental changes or to obtain accurate measurement, the balance should generally be calibrated before use. The calibration methods are divided into internal calibration and external calibration. The "JA" series electronic sky produced in Germany, Switzerland and Shanghai have calibration devices on average. If the manual is not read carefully before use, it is easy to ignore the "calibration" operation, resulting in large weighing error. The following takes the ja1203 electronic balance of Shanghai balance instrument factory as an example to illustrate how to calibrate the balance externally. Methods: lightly press the cal key. When the display shows cal-, it will release, and the display will show cal-100, where "100" is a flashing code, indicating that 100g standard weight is required for calibration weight. At this time, put the prepared "100g" calibration weight on the weighing plate, and the display will appear "----" waiting state. After a long time, the display will appear 100.000g. Take the calibration weight, and the display should appear 0.000g. If it is not zero, it will be reset. 1. Self locking: self locking is generally inversely proportional to the transmission effect, and repeat the above calibration operations. (Note: in order to obtain accurate calibration results, it is better to repeat the above calibration)

the cleaning screw must not be used. People with steel workers believe that the heavier the object weighed within the range of the electronic balance, the greater the damage to the balance. This understanding is not entirely correct. The maximum safe load of a general weighing instrument is the maximum static load that it can bear without permanently changing its measuring performance. As the electronic balance adopts the principle of automatic compensation circuit of electromagnetic force, when the scale is loaded (pay attention not to exceed the weighing range), the electromagnetic force will push the scale back to the original balance position to balance the electromagnetic force with the gravity of the weighed object. As long as the weighing within the allowable range has little impact on the balance, it will not affect the accuracy of the electronic balance due to long-term weighing

II. Maintenance of electronic balance

1. Place the balance on a stable workbench to avoid vibration, airflow and sunlight

2. Adjust the level bubble to the middle position before use

3. The electronic balance shall be preheated according to the requirements of the manual

4. When weighing volatile and corrosive items, they should be placed in closed containers to avoid corrosion and damage to the electronic balance

others spent thousands of yuan more. 5. They often carry out self calibration or regular external calibration on the electronic balance to ensure that it is in the best state

6. If the electronic balance breaks down, it should be repaired in time. It is not allowed to work with "disease"

7. Do not overload the operating balance to avoid damaging the balance

8. If the electronic balance is not used for a long time, it should be stored temporarily

Copyright © 2011 JIN SHI