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ADU71 User Manual
7b) Connecting to Voltage Input Devices.
Voltage input devices can also be connected to the ADU71 LOOP output provided the input connections are
terminated with an appropriate resistor. For 1-5VDC input devices the input should be shunted with a 250 ohm
resistor to convert the 4-20mA current signal to a 1-5VDC signal as shown in Figure 3.
CAUTION: Ensure the resistor is correctly and firmly connected to the device input terminals. If the resistor is
not correctly connected, or open circuit, the ADU71 will apply 24VDC to the input of the device under control
when the ADU71 loop current is enabled. This may damage the input circuitry of the device under
control.
Figure 3 : ADU71 driving a 1-5VDC input VFD or valve.
If the device under control has a 0-5VDC input, the connections are identical to Figure 3, however, the ADU71
LOOP is programmed to provide 0-20mA to the loop as shown in Figure 4.
Figure 4 : ADU71 driving a 0-5VDC input VFD or valve.