Unit name Function
Additional I/O Power
Supply Unit
This NX Unit provides additional I/O power supply.
Use this NX Unit in the following cases.
a. When the I/O power supply capacity is insufficient
• When the total current consumption for the I/O power supply exceeds the maxi-
mum current of I/O power supply of the Communications Coupler Unit
• When a voltage drop in the I/O power supply causes the voltage of the I/O pow-
er supply to go below the voltage specifications of the I/O circuits or connected
external devices
b.
Separating the I/O power supply
• When connected external devices have different I/O power supply voltages
• When separating the power supply systems
When the I/O power supply
becomes the following states
for the subsequent NX Units.
- When it exceeds the maximum
current of I/O power supply
- When it goes below the voltage
specifications of the connected
external devices
I/O power
supply
Unit power
supply
Case (b)
I/O power
supply
Internal
power
supply
circuit
Case (a)
Communications
Coupler Unit
NX Unit
I/O power
supply
Unit power
supply
I/O power
supply
Additional I/O
Power Supply Unit
Separated by Additional I/O
Power Supply Unit
Internal
power
supply
circuit
Communications
Coupler Unit
NX Unit Additional I/O
Power Supply Unit
Separated by Additional I/O
Power Supply Unit
- When different I/O power supply voltage are used.
- When separating the power supply systems.
The NX Unit power supply of the Additional I/O Power Supply Unit is connected to the
NX Unit on the left through the NX bus connector
.
4 Installation and Wiring
4-18
NX-series System Units User's Manual (W523)