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 Communication Control 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.
Communication
Control Unit
NX Unit
I/O power
supply
I/O power
supply
•
When different I/O power supply voltage is used.
•
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
Case (a)
Internal
power
supply
circuit
Unit power
supply
NX Unit
I/O power
supply
I/O power
supply
Case (b)
Internal
power
supply
circuit
Unit power
supply
Separated by Additional
I/O Power Supply Unit
Additional I/O Power Supply Unit
Separated by Additional
I/O Power Supply Unit
Additional I/O Power Supply Unit
Communication
Control Unit
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
4-23
NX-series System Units User's Manual (W523)
4-4 Wiring the Power Supply to the Communication Control Unit
4
4-4-3 Power Supply-related Units and Wiring Methods