YASKAWA MEMOCON GL120 User Manual page 270

3) Connecting DC Input Devices with Different Voltage Ratings
Normally, the power supply voltage of the input device should match that of the DC
Input Module. The following table shows examples of input devices with different
voltage ratings and advises whether or not they may be connected to the DC Input
Module.
Open collector output (V1 < V2)
Input Device
Connection Can be connected.
V1: Input signal power supply
V2: Input device power supply
V1
24 VDC
Output with a diode (V1 < V2)
Input Device
Connection Can be connected.
V1: Input signal power supply
V2: Input device power supply
V1
24 VDC
V2
48 VDC
Output with a resistor and LED (V1 < V2)
Input Device
Connection Cannot be connected.
V1: Input signal power supply
V2: Input device power supply
V1
24 VDC
V2
48 VDC
Input device
V2
48 VDC
Input device
When the input device is OFF, current indicated by the dot-
ted line in the figure on the left may flow, causing the LED
of the input device to glow dimly.
Input device
6-43
6.4 Precautions on Wiring
DC Input Module
+Common 1 Photocoupler
9
Input
DC Input Module
+Common 1
Photocoupler
9
Input
DC Input Module
+Common 1
9
Photocoupler
Input
6