Selecting The Io Power Supplies - Omron PROFINET NX-PNC202 User Manual

5 Designing the Power Supply System
Precautions for Correct Use
Consider the inrush current when the power supply is turned ON and select a Unit power sup-
ply with sufficient extra capacity. The inrush current when power is turned ON may prevent the
Unit power supply from operating correctly.
5-4-2

Selecting the IO Power Supplies

This section describes how to select the IO power supplies for the Profinet IO Device Terminal.
Recommended Power Supplies
Use an SELV power supply that meets the following conditions for the IO power supply.
• Has overcurrent protection.
• Has double or reinforced insulation between the input and output.
• Has an output voltage of 5 to 24 VDC (4.5 to 28.8 VDC).
*1. Use an output voltage that is appropriate for the IO circuits of the NX Units and the connected external
devices.
Recommended Power Supplies: S8JX Series (manufactured by OMRON)
Calculating the Required Power Supply Capacity of the IO Power
Supply
Use the calculation method that is described in 5-3 Designing the IO Power Supply System on page 5-9
and calculate the total current consumption from the IO power supply and the required power supply
capacity of the IO power supply.
Unlike the Unit power supply, it is not necessary to use only one IO power supply to supply power to the
entire IO Device Terminal.
Precautions for Correct Use
Consider the inrush current when the power supply is turned ON and select an IO power supply
with sufficient extra capacity. The inrush current when power is turned ON may prevent the IO
power supply from operating correctly.
5-4-3 Selecting Protective Devices
This section describes how to select protective devices (e.g., breakers and fuses) to protect against
short circuits and overcurrents in external circuits.
Overcurrent is the current that flows when an excessive load is connected and one of the following rat-
ings is exceeded.
• For the Unit power supply, the rating of the NX Unit power supply capacity or of the current capacity
of the power supply terminals
• For the IO power supply, the rating of the maximum IO power supply current or of the current capacity
of the power supply terminals
For the above ratings for the PROFINET Coupler Unit, refer to 3-1-3 PROFINET Coupler Unit Specifi-
cations on page 3-4. For the ratings of NX-series power supply-related Units, refer to the NX-series
System Units User's Manual (Cat. No. W523).
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NX-series PROFINET Coupler Unit User's Manual (W623)