NX Unit Power Supply vs. I/O Power Supply
The power supply system for the CPU Rack of the NX-series CPU Unit consists of two power supply lines: one for NX Unit power and the other for I/O power.
The Unit Power Supply provides power for the internal circuits of the CPU Unit, as well as NX Unit power for the NX Units. Up to 10 W of NX Unit power can be delivered to NX Units via the power supply terminals on the CPU unit.
The I/O Power Supply provides power to the I/O circuits of each NX Unit on the CPU Rack, as well as to external devices connected to the NX Units. Some NX Units receive I/O power through the NX bus, and others receive from external devices.
You may need additional power supply Units for NX Unit power or I/O power according to the total power consumption or the total current consumption of NX Units on the CPU Rack.
NX Unit Power supply requirement (NX-PD____)
Each NX unit added to the rack draws a certain amount of power from the NX bus for its internal circuits. For example, the NX-ID5142-1 draws 0.85W per unit.
If the total power drawn by the units on the rack exceed the available NX Unit power provided by the NX bus, SYSMAC Studio will display a warning sign in the CPU Rack page:
Use an extra NX Unit Power supply (NX-PD) to add another 10W to the available NX Unit power supply.
I/O Power supply requirement (NX-PF____)
Warning
The table below list the NX units and their I/O power supply requirement. When placing NX IO on a PLC rack, you will need a minimum of 1 x NX-PF card if the combination is stated in the below table:
If any NX Unit on the CPU Rack receives I/O power through the NX bus, you need to prepare an external I/O power supply device. Add one or more NX-PF Additional I/O Power Supply Units when I/O power is supplied from the NX bus to NX Units connected to the CPU Unit.
Please note that SYSMAC Studio does not display any warning when the I/O Power supply requirements are not met.
More information
Find more information in the CPU hardware manual of your CPU: Section 4 Designing the Power Supply System.
NX1P2: Nx-Series Nx1P2 Cpu Unit Hardware Users Manual En.Pdf (W578)