Omron NX Series Hardware User Manual page 128

4 Designing the Power Supply System
Current Breaking/fusing time
6 A 1 min max.
12 A 15 s max.
21 A 5 s max.
30 A 2.5 s max.
Installation Locations for Protective Devices
Install protective devices for the Unit power supply and I/O power supply in the locations that are
shown in the following figure.
Block that the CPU Unit supplies Unit power supply.
Internal
circuits
Internal
power
supply
circuit
Unit power supply terminals
Unit power supply
However, fewer protective devices may be required when the current consumption of each block does
not exceed the rated current.
An example of this is provided below.
• Using Unwired Unit Power Supply Terminals
In this example, the current consumption from each power supply is as follows:
Current consumption from Unit power supply: I_unit1 + I_unit2 ≤ Lowest rated current
Current consumption from I/O power supply for NX Units: I_io1 + I_io2 ≥ Lowest rated current
4-26
Block that an Additional I/O
Power Supply Unit 1
supplies I/O power supply.
Additional
NX-series
I/O Power
NX502 CPU Unit
Supply Unit
1
Internal circuits
NX Unit power supply
I/O power supply
I/O power
External device
supply
terminals
Protective Protective
device device
I/O power supply
(24 VDC) (24 VDC, etc.)
Block that an Additional NX Unit Power
Supply Unit supplies Unit power supply.
Additional
NX Unit
Power
Supply Unit
Power
supply
I/O power
supply
Unit power
terminals
supply
Protective
terminals
device
NX-series NX502 CPU Unit Hardware User's Manual (W629)
Block that an Additional I/O
Power Supply Unit 2
supplies I/O power supply.
Additional
I/O Power
Supply Unit
2
NX Unit power supply
I/O power supply
End
Cover
External device
Protective
device
*1