Digital multimeter to measure the frequency of the UPS powering method
For UPS power supply. The stability of its output voltage is an important parameter, the output frequency is also very important. But not directly with a digital multimeter frequency block to measure, because its frequency block can withstand the voltage is very low. Only a few volts. This can be connected to the output of the UPS power supply 220V / 6V or 220V / 4V step-down transformer, the voltage is reduced, without changing the frequency of the power supply, and then the frequency block and the output of the transformer connected to the frequency can be measured out of the UPS power supply.
In general, the use of digital multimeter or to use the correct method of operation, can not understand the principle and function to blindly use, reasonable in accordance with the correct method of operation is also conducive to the digital multimeter better for us to use, to extend the life of the instrument.
Frequency is the number of cycles a signal completes per second. Some digital multimeter can be measured, such as the FT215 digital multimeter by calculating the number of times per second the measured signal and trigger level intersection to measure the frequency of a signal. The trigger level for all ranges is the same as the COM terminal level. Under the AC measurement function, press SHIFT to start and close the frequency measurement function. Frequency measurement applies to AC only. During frequency measurement, the analogue pointer display and range display indicate the current AC voltage or current. Use the manual range function to incrementally select a lower range for stable readings.
Adjustment and Repair Methods for Each Part of the Multimeter
Pointer meter (analogue meter)
Correct with the minimum current gear, have a standard meter and power supply, resistance box.
Balance adjustment: with the power supply to the pointer to the centre, left and right before and after, place the multimeter, the pointer swing should be within the error range, not in should be adjusted dovetail.
Adjustment of mechanical zero: the surface mechanical zero adjustment knob should be in the middle point, adjust the back adjuster, so that it is in the zero point.
Fullness adjustment: the signal source is adjusted to fullness current, the pointer should be in fullness, not in should adjust the internal potentiometer.
Shift, adjust the input current, fullness does not match and requirements, adjust the corresponding shunt resistor
