First, electronic scales and classification
It is called the electromagnetic force balance gravity balance object called electronic balance. Its characteristics are accurate and reliable weighing, display clear and fast
Household electronic scales and automatic detection system, easy auto-calibration device and overload protection devices.
By precision electronic balance can be divided into the following categories:
1, the maximum amount of ultrafine electronic weighing scales ultra microbalance is 2 to 5g, its value is less than the scale division (max) weighing 10-6 (power), as Mettler UMT2 type of electronic balance amount of electrons belonging to Advanced Micro Devices balance.
2, weighing microbalance microbalance generally 3 to 50g, dividing its value is less than (max) weighing 10-5, such as the AT21 Mettler electronic balance and Sartoruis S4 of electronic balance.
3, semi-microbalance is generally semi-microbalance weighing 20 to 100g, dividing its value is less than (max) weighing 10-5, such as equality of AE50 Mettler electronic balance and Sartoruis the M25D electron days belong to this class.
4, constant electronic weighing scales such maximum balance is generally from 100 to 200g, dividing its value is less than (max) weighing 10-5, such as Mettler AE200 type of electronic balance and Sartoruis the A120S, A200S electron-day average belong to constant electronic balance.
5, electronic analytical balance analytical balance in fact, is a constant balance, semi-microbalance microbalance and ultra-micro balances in general.
6, precision electronic balance electronic balance is such accuracy level Ⅱ grade electronic balance collectively.
Second, the purchase and use precautions
Using electronic balance four elements
The first warm-up ahead. Electronic balance usually require preheating prior to use, and the warm-up time for each balance often different, generally speaking, the higher the level of accuracy of the balance, the longer warm-up time required, according to the instructions for use of the balance requirements preheating, the preheating time may be extended if necessary (usually the lower the ambient temperature, the longer warm-up time). In fact, many users in the use of space usually are ready to use, so there is no guarantee the metrological performance of the balance. Therefore, electronic scales preheating is related to the accuracy of the focus.
Second, the environmental conditions. Environmental conditions are also an important factor in performance of electronic balance measurement. Electronic balance operating instructions does not specify particular temperature limit, the balance should work at a temperature of -10 ℃ ~ 40 ℃; if you specify particular temperature limit, the balance should work under specified temperature conditions; electronic the balance of the humidity is also required, such as grade ⅰ balance requirements relative humidity less than 80%.
The third is a horizontal state. General are high-precision electronic scales with spirit level and leveling device, in use, should regularly check the level of state balance. In fact, some users often neglect to check the level of state balance (electronic balance due to the movement or other reasons, often resulting in corners or uneven levels, etc.) which is caused mainly due to the balance of inaccurate data.
Fourth, the calibration at any time. Some people think, electronic scales after a test period, within the validity period is accurate, but often ignore the importance of calibration, even without calibration. As everyone knows, electronic scales due to environmental conditions change in use, human factors, performance measurement often subtle changes occur, which we need to be calibrated daily use. So, we like how to calibrate it? Electronic balance should be daily or before each use for calibration, if necessary, increase the calibration [2] frequency. Calibration weights, in theory, the higher the level the better, generally should be used in weight error is less than 1/3 of the maximum permissible error balance can and should be sent to the quality supervision department regularly scheduled inspection, if found to exceed the standard error, to send timely quality supervision department, to avoid losses and the emergence of the phenomenon of harm consumers.
1, (1) How to choose an electronic balance electronic scales should choose from the absolute accuracy of electronic balance (scale interval e) weighing up to consider whether the
Portable electronic scale accuracy. Like the election 0.1mg or 0.01mg precision balance precision balance, should not generally be said to be one ten thousandth or one hundred thousandth precision balance, because some foreign manufacturers are used to measure the relative accuracy of the scale, otherwise buy the balance can not meet the needs of users. For example, we encountered such a situation in practice, using a ruler actual scale interval d is 1mg, scale verification scale interval e is 10mg, the largest weighing 200g of Mettler electronic balance for weighing 7mg objects, this is not an accurate result: in the "JJG98-90 non-automatic scale pilot test procedures" stipulates that the maximum permissible error of scale verification scale interval "e" of the same order of magnitude, this balance to the maximum allowable error is 1e, obviously not weighing 7mg objects; weighing 15mg objects with such balance is not the best choice, because the relative error of the test results will be great, should choose a higher level of balance, some manufacturers at the factory It specifies the minimum weighing value. So we buy and use electronic day usually must consider precision.
(2) selection of the weighing range of requirements in addition to watching their precision electronic balance, but also look at the largest weighing whether to meet the range of needs. The maximum payload is usually taken to a little insurance factor, which is commonly used to load and then relax some, not the better.
2, on the electronic balance calibration (be sure to read the instructions carefully before using) in the test (test), we found that the balance be tested for the first time measured error is greater reason, a considerable part of the instrument, at longer intervals within not calibrated, and that the balance displays zero can be directly weighed. (It should be noted that the electronic balance indicates zero power, can not explain the data accuracy of weighing scales meet the test criteria, only shows zero balance stability qualified because a balance measure qualified or not, need to consider other technologies compliance indicators). Due to long storage time, position, or changes in the environment in order to obtain accurate measurements, the balance prior to use in general should be calibrated to operate. Calibration and calibration method divided into two kinds of external calibration. German production of Sartorius, Mettler produced in Switzerland, produced in Shanghai "JA" series of electronic-day average of the calibration device. If you do not read the instructions carefully before using it is easy to ignore the "calibration" operation, resulting in greater weighing error. Below Shanghai Balance Instrument Factory JA1203 electronic balance an example of how to balance performs outside calibration. : When you tap the CAL key when the display appears CAL-, that is let go, the display would appear CAL-100 where "100" is flashing code indicating that the required calibration weights 100g standard weight. At this time ready to put the "100g" calibration weight put on the pan, the display appears "----" wait state, the display appears after a long time 100.000g, take calibration weights, the display should appear 0.000g , if there is not a zero, then cleared again, then repeat the calibration. (Note: To get the best results accurate calibration Repeat calibration)
Some people think that the more weight within the range of electronic balance scale objects weighing the balance of the damage will be. This understanding is not entirely correct. Usually weighing maximum safe load that it is able to withstand, without making a permanent change in the measurement performance of the maximum static load. Since the electronic balance using electromagnetic force automatic compensation circuit principle, when the pan is loaded (be careful not to exceed the weighing range), the electromagnetic force will push the pan back to the original position of equilibrium, so that the electromagnetic force and gravity is called object phase balance, as long as within the allowable range weighing affect the size of the balance is small, weighing the long-term will not affect the accuracy of electronic balance.
Third, electronic balance Maintenance
1, the balance on a stable table to avoid vibration, air and sunlight.
2, before using the bubble level meter to adjust to the middle position.
3, electronic balance requirements specification should be preheated.
4, weighing volatile and corrosive materials, to be served in a closed container to prevent corrosion and damage electronic balance.
5, often electronic balance from the school or outside the school on a regular basis to ensure that it is in the best condition.
6, if the failure of electronic balance should be timely maintenance, not take "sick" work.
7, the operation does not overload the balance use to avoid damage to the balance.
8, if the long-term without electronic balance should be temporary collections as well.
Fourth, the use of ordinary household electronic scales, precautions and calibration methods:
Specifications:
Model: SF400, SCA301, W108B; TH1000, TH5000 and the like. Specifications: 7000g * 1g, 5000g * 1g, 1000g * 0.2g, 500g * 0.1g; each scale is only a measuring range and accuracy, for example, 5000g * 1g represents the largest weighing 5000 grams (range is 5000g), dividing the value of 1 gram . Second, the key functions:
Household electronic scale key shape may vary, but the most basic three functions are as follows:
1, ON / OFF: power switch, as the power in the air, said the case, about 100 seconds will automatically shut down. Many electronic scales will add a vertical circular symbol represents the key to open.
2, TARE alone or letter "T", said: cleared TARE key; press the key to make clear the tare scale back to zero. For example, containers placed on the scale, press this button to zero the scale, again added to the liquid containers, scales show only the weight of the liquid. 3, MODE, "UNIT" or "U": unit conversion button; each time you press the "MODE" button, between "g" and "oz" conversion. Ounces (oz) for foreign common unit, for example, gold is usually quoted in US dollars at a ounces. g for gram, 1 kg = 1000 g = 2 kg. Third, pay attention: 1, the boot does not display: Check that the battery is properly installed power is sufficient, if the insulating plastic sheet removed.
2, electronic scales smoothly put the object to be weighed gently on the pan after the weight of the object found quickly won over the range, try to cherish electronic scales. 3, long-term without electronic scales, remove the battery to avoid battery leakage damage your electronic scales.
Household electronic scale calibration method:
1, in the off state, press and hold the "MODE" button and then press and hold "ON / OFF", wait until after the display shows a group code value release both keys, for example "-7484", press "ON / OFF" button will prompt you to put the appropriate number of grams of weight, such as 5000 g calibration weights 2000 grams, the display will indicate "2000", put the corresponding weight of the weight again after pressing "ON / OFF "button, the display will quickly show" PASS "indicates that the calibration is complete. After the reboot you can normally use.
2, if there is no weight, it can be weighed on an electronic scale corresponding to the weight of an object, such as a glass child, appropriate water addition and subtraction, repeatedly fine-tuning, but also a quasi-adjustable weights.
