Precision balance is a comprehensive product of sensor technology, analog electronics technology, digital electronics technology and microprocessor technology development. It has many functions such as automatic calibration, automatic display, taring, automatic data output, automatic fault tracing and overload protection. .
Precision balances usually use electromagnetic force sensors (see load cells) to form a closed-loop automatic adjustment system with high accuracy and good stability. The working principle of the electronic balance: When the weighing object is added to the weighing plate, the position detector signal of the sensor changes, and the current in the sensor coil is increased by the feedback of the amplifier, which generates a feedback force in the constant magnetic field. The applied load is phase-balanced; at the same time, the voltage value of the current on the measuring resistor Rm is sent to the microprocessor through the filter and the analog-to-digital converter for data processing, and the nominal mass value is automatically displayed by the display after the Zui.
How to use precision balance:
Precision balance is an indispensable instrument in quantitative analysis. It is a guarantee to obtain reliable analysis results by fully understanding the performance of the instrument and mastering its use. There are many types of precision balances, such as ordinary precision balances, semi-automatic/automatic plus-type electro-optic projection damping precision balances and electronic precision days. The following is an introduction to the use and precautions of precision balances.
Method of operation
1. Check and adjust the balance to the horizontal position.
2. Check the power supply voltage beforehand (if necessary, configure the voltage regulator), and warm up to the required time according to the requirements of the instrument.
3. After preheating for a sufficient time, the balance switch is turned on and the balance automatically performs sensitivity and zero adjustment. After the stability mark is displayed, formal weighing can be performed.
4. When weighing, place the clean weighing bottle or weighing paper on the weighing pan, close the side door, press the peeling button lightly, the balance will automatically check the zero point, and then gradually add the substance to be weighed until the required weight.
5. The weight of the substance is the actual value displayed on the display when the “→†mark appears in the lower left corner of the display.
6. At the end of weighing, the weighing bottle (paper) should be removed in time, the side door should be closed, the power supply should be cut off, and the usage registration should be completed.
Precautions for precision balances
1. The balance should be placed on a firm and stable cement table or wooden table. The room should be clean, dry and relatively constant temperature, and the light should be directly exposed to the balance.
2. If the electronic precision balance is not used for a long time, it should be energized and preheated regularly, once a week, and preheated for 2 hours each time to ensure that the instrument is always in good condition.
3, volatile, corrosive, strong acid and alkali substances should be weighed in a weighing bottle with a lid to prevent corrosion of the balance.
4. When weighing, the material should be taken from the side door. When reading, the door should be closed to prevent the air from flowing and causing the balance to swing. The front door is only used when servicing or removing residual materials.
5. The moisture-absorbing agent (such as silica gel) should be placed in the balance box. When the moisture-absorbing agent absorbs water and discolors, it should be immediately baked at a high temperature to ensure moisture absorption.
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