Hitachi WJ Series User Manual page 89

Chapter 5
Cautions when using multiple inverters
!
 If a common input (switch, etc.) is used for multiple inverters and the timing of power-on is
different, the current may run around as shown in the figure below, and it may be recognized as
ON even if the input is OFF. In that case, be sure to insert a diode (rated 50 V/0.1 A) in the
positions shown in the figure to prevent the current flow round.
■ Sink logic
Short-
circuit
wire
Short-
circuit
wire
Switch OFF
If there is no diode, the current will flow round and
the input will turn on even though the switch is off.
■ Source logic
Short-
circuit
wire
Short-
circuit
wire
Switch OFF
If there is no diode, the current will flow round
and the input will turn on even though the
switch is off.
Power ON
P24
PLC
L
Input
1
Diode added
Power OFF
P24
PLC
L
1
Power ON
P24
PLC
L
Input
1
ON
Diode added
Power OFF
P24
PLC
L
1
5-4-11
Wire Connection
Power ON
P24
PLC
L
1
Power OFF
P24
PLC
L
1
Switch OFF
Diodes are installed instead of the short-circuit
wires to prevent current flow round.
Power ON
P24
PLC
L
1
P24
PLC
L
1
Switch OFF
Diodes are installed instead of the short-circuit
wires to prevent current flow round.
Input
Input
OFF
Power OFF