Measuring Dc Current - Extech Instruments PRC50 User Manual

6.3 Measuring DC Current

Step 1: Ensure that the test lead cables are not connected to the instrument or device under test.
Step 2: Using the function key (mA), select the DC Current measurement function.
Step 3: Connect the test lead cables to the measuring terminals of the instrument under test.
Step 4: The selected function, the measured value, and the unit is shown in the upper area of the LCD.
6.3.1 mA % Display
In the mA measurement mode, the preset value is displayed on the primary numerical display area and the mA% is
displayed on the smaller, secondary numerical display area. See the equation below.
100 (current measured value mA-4mA)
mA %= %
16 mA
6.3.2 Using the Calibrator as a 24-V Loop Power Supply
This function helps to switch ON a 24V loop power supply connected in line with the measured DC current circuit, in which
the calibrator can be used as a loop power supply that can calibrate a 2-wire converter:
Step 1: When the calibrator is in the current measurement mode, pressing the〔LOOP〕key causes the LCD to show the
LOOP symbol and the built-in 24V loop power of the calibrator will be switched ON.
Step 2: Connect the calibrator with the loop current terminals of the converter as shown in Figure 11.
Figure 11 – A 24v loop power circuit supply
Note: Since the function discussed above requires a significant amount of DC current (25 mA), battery operation will reduce
the battery life considerably.
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