Omron NX Series Hardware User Manual page 116

4 Designing the Power Supply System
Calculating the Total Current Consumption from the I/O Power Sup-
ply
The total current consumption from the I/O power supply from the NX bus is the total of the following
current consumptions.
• The current consumption from the I/O power supply that is required for the Additional I/O Power
Supply Unit and for the NX Units that are connected to the Additional I/O Power Supply Unit
• The current consumption between the NX Units and the connected external devices
Current consumption item
Current consumption from I/O power
supply
Current consumption between the NX
Units and the connected external de-
vices
l Calculation Example of I/O Power Supply Capacity
An example of calculating the required power supply capacity of the I/O power supply is given be-
low.
Configuration and Conditions
Additional I/O Power
Supply Unit
NX-PF0730
I/O
power
supply
(24 VDC)
I/O power supply voltage
Inputs Number of inputs used (that turn ON simultaneously) 4 points
Current consumption of connected input devices
Outputs Number of outputs (that turn ON simultaneously)
Load current of connected loads
Current consumption of connected output devices
I/O power is supplied to the NX-ID3317 and NX-OD3121 from the NX bus.
a. Unit Specifications
4-16
This is the current that is consumed by the internal circuits that operate on the I/O
power supply.
Specific values are given in the user's manuals for individual Units.
This is the current that is consumed between the NX Units and the connected exter-
nal devices.
For example, this is the current consumed by a Digital Input Unit to supply power to
photoelectric sensors or to turn ON the input circuits in the Digital Input Unit.
The current consumption depends on the type of I/O circuit in the NX Unit, the num-
ber of I/O points that are used, and the current consumption of the connected exter-
nal device. It must be calculated for each NX Unit.
Digital Input Digital Output
Unit Unit
NX-ID3317 NX-OD3121
End Cover
Connected
Connected
output
input
devices
devices
(loads)
Item
NX-series NX102 CPU Unit Hardware User's Manual (W593)
Description
Condition
24 VDC
50 mA/point
4 points
125 mA/point
50 mA/point