Sinking Inputs, External Supply; Sourcing Inputs, External Supply - Hitachi L200 Series Instruction Manual

The two diagrams below show input wiring circuits using an external supply. If using the
upper wiring diagram, be sure to use a diode with the external supply. This will prevent a
power supply contention in case the SR/SK switch is accidentally placed in the incorrect
position. Be sure to use the correct SR/SK switch position shown for each wiring
diagram.

Sinking Inputs, External Supply

SR/SK switch = SK position
Open collector outputs,
NPN transistors
Field device
+V
+
1
–
5
GND

Sourcing Inputs, External Supply

SR/SK switch = SR position
PNP transistor
sourcing outputs
Field device
1
5
+
–
24V
GND
* *
24V
+
–
Input
switches
Logic GND
* Note: If the external power supply GND is (optionally)
connected to [L], then install the above diode.
24V
+
–
Input
switches
Logic GND
L200 Inverter
L200
PCS
SK
SR
SK
SR
1
Input
circuits
5
L
L200
PCS
SK
SR
SK
SR
1
Input
circuits
5
L
4–11
24V
+
–
24V
+
–