How to use a multimeter to test a 4~20mA sensor
There are two measurement methods:
1. Pass the current level test of the multimeter. The steps are as follows:
The red test lead of the multimeter is connected to the mA hole, and the black test lead is connected to COM.
Adjust the multimeter to the DC mA range.
The red test lead of the multimeter is connected to the positive terminal of the 4-20mA sensor output, and the black test lead is connected to the negative terminal of the 4-20mA sensor output.
Read the reading from the display area of the multimeter, and the reading is the current value.
2. Measure the current value through the multimeter's 10,000-voltage range. For multimeters without current test functions, you can measure the current value through voltage. The steps are as follows:
At the 4-20mA sensor output, connect a sampling resistor of about 100 ohms.
The red test lead of the multimeter is connected to the mA hole, and the black test lead is connected to COM.
Adjust the multimeter to the DC V position.
The red test lead of the multimeter is connected to the positive terminal of the 4-20mA sensor output, and the black test lead is connected to the negative terminal of the 4-20mA sensor output.
Read the reading from the display area of the multimeter. The reading is the voltage value. Divide the reading reading by the resistance value (for example, 100 ohms) to get the current value.
Use the DC current function of the multimeter, the 20mA setting (if not, select the 100mA setting), and directly test the sensor output. If it is a desktop digital multimeter, you can also use any sensor function to let the instrument directly test the physical quantity sensed by your sensor. Wiring method: connect the red test lead to the green wire, and connect the black test lead to the yellow wire.
