Refer to Designing the Power Supply System and Wiring in the user's manual for the connected
Communications Coupler Unit for details on Units to which I/O power is supplied in a Slave T
ermi-
nal.
Additional Information
NX-series Power Supply-related Units
The following three NX-series Units are related to power supply.
• Additional NX Unit Power Supply Units
•
Additional I/O Power Supply Units
• I/O Power Supply Connection Units
Refer to NX-series System Units User’s Manual (Cat. No. W523) for the specifications of these
Units.
For a complete list of the latest power supply Units in the NX Series, refer to the product catalog
or OMRON website, or contact your OMRON representative.
4-2-3
Calculating the Total Current Consumption from I/O Power Sup-
ply
The total current consumption of I/O power supplied from the NX bus must be within the range of the
maximum I/O power supply current of the Communications Coupler Unit or the Additional I/O Power
Supply Unit. However
, when an Additional I/O Power Supply Unit is connected to the CPU Rack of a
CPU Unit, the maximum I/O power supply current value may be smaller than that of the Additional I/O
Power Supply Unit. For example, the maximum I/O power supply current for the CPU Rack of an
NX1P2 CPU Unit is 4 A. Refer to the hardware user’
s manual for the CPU Unit to which NX Units are
connected for information on the restrictions for the CPU Rack.
To confirm this and to calculate the I/O power supply capacity, calculate the total current consumption
of the I/O power supply from the NX bus.
Note that the current consumption from I/O power supply indicated in the data sheet for each Unit type
does not include the load current of any external connection load and current consumption of any con-
nected external devices.
The total current consumption from I/O power supply of the High-speed Analog Input Units is calculat-
ed as follows:
Refer to A-1 Data Sheet on page A - 2 for the current consumption from I/O power supply for each
High-speed Analog Input Unit model.
Precautions for Safe Use
The I/O power supply current for the CPU Rack with an NX-series CPU Unit should be within
the range specified for the CPU Unit model. For example, use the NX1P2 CPU Unit with a cur-
rent of 4 A or less. Using the currents that are outside of the specifications may cause failure or
corruption. Refer to the user’s manual for the connected CPU Unit for the I/O power supply cur-
rent for the CPU Unit model.
Total Current Consumption from I/O Power Supply from the NX Bus
The total current consumption from I/O power supply from the NX bus is the sum of the following: the
current consumption from I/O power supply of the NX Unit that supplies the I/O power from the NX
4 Installation and Wiring
4 - 5
NX-series Analog I/O Units User’s Manual for High-speed Analog Input Units (W592)
4-2 Power Supply Types and Wiring
4
4-2-3 Calculating the Total Current Consumption from I/O Power Supply