Maintenance of weighbridges and electronic scales using multimeter skills
1. How to use
1. Before use, read the relevant instruction manual carefully, and be familiar with the functions of the power switch, range switch, jack, and special jack.
2. Put the power switch in the ON position.
3. Measurement of AC and DC voltage: Turn the range switch to the appropriate range of DCV (DC) or ACV (AC) as required, insert the red test lead into the V/Ω hole, insert the black test lead into the COM hole, and connect the test lead to the circuit under test in parallel , the reading is displayed.
4. Measurement of AC and DC current: Turn the range switch to the appropriate range of DCA (DC) or ACA (AC), insert the red test lead into the mA hole (<200mA) or 10A hole (>200mA), and insert the black test lead into the COM hole , and connect the multimeter in series in the circuit under test. When measuring DC flow, the digital multimeter can automatically display the polarity.
5. Resistance measurement: Turn the range switch to the appropriate range of Ω, insert the red test lead into the V/Ω hole, and insert the black test lead into the COM hole. If the measured resistance value exceeds the maximum value of the selected range, the multimeter
The meter will display "1" and a higher range should be selected. When measuring resistance, the red test lead is positive and the black test lead is negative, which is just the opposite of the pointer multimeter. Therefore, when measuring polar components such as transistors and electrolytic capacitors, you must pay attention to the polarity of the test leads.
2. Precautions for use
1. If the voltage or current to be measured cannot be estimated in advance, you should switch to the highest range and measure once, and then gradually reduce the range to a suitable position according to the situation. After the measurement is completed, the range switch should be set to the highest voltage position, and the power supply should be turned off.
2. When the scale is full, the meter only displays the number "1" in the highest digit, and the other digits disappear. At this time, a higher range should be selected.
3. When measuring voltage, the digital multimeter should be connected in parallel with the circuit under test. When measuring current, it should be connected in series with the circuit under test, and it is not necessary to consider positive and negative polarity when measuring DC flow.
4. When the AC voltage is misused to measure the DC voltage, or the DC voltage is misused to measure the AC voltage, the display will display "000", or the number on the low digit will jump.
5. It is forbidden to measure high voltage
(above 220V) or high current (above 0.5A) change the range to prevent arcing and burn the switch contacts.
6. When " ", "BATT" or "LOW BAT" is displayed, it means that the battery voltage is lower than the working voltage
