Hitachi CONVENTION 14 Instruction Manual page 159

4 − 10
4 10
The two diagrams below show input wiring circuits using an external supply. If using
the "Sinking Inputs, External Supply" in below wiring diagram, be sure to remove the
short bar, and use a diode (*) with the external supply. This will prevent a power supply
contention in case the short bar is accidentally placed in the incorrect position. For the
"Sourcing Inputs, External Supply", please connect the short bar as drawn in the
diagram below.
Sinking Inputs, External Supply
Short bar = Removed
Field device
+
-
Open collector outputs,
NPN transistors
Sourcing Inputs, External Supply
Short bar = [PCS] – [L]
PNP transistor
sourcing outputs
Field device
+
-
*
24V
GND
1
5
1
5
24V
GND
P24
*
24V
PCS
+
-
Logic GND
L
1
5
Input switches
* Note: If the external power supply to GND is (optionally)
connected to [L], then install the above diode.
Short bar
P24
24V
+
PCS
-
L
1
5
Input switches
X200
24V
Input common
+
-
Input
circuits
X200
24V
Input common
+
-
Input
circuits