Omron PROFINET NX-PNC202 User Manual page 85

● Total current consumption from the Units
Example:
PROFINET
I/O power
(24 VDC)
Power Consumption of Individual Units
*1
(1): 0 A (Supplied from the NX bus.)
(2) and (3): 1.5 A each (Supplied from the NX bus.)
(4) and (5): 0 A (Supplied from external source.)
(6) and (7): 0.5 A each (Supplied from the NX bus.)
*1. The current consumption of the PROFINET Coupler Unit is not actually 0 A. However, a value of 0 A is used
in this calculation example.
In actual calculations, use the current consumption from the IO power supply that is given elsewhere in this
manual.
 Outline
Find the IO power supply voltage of the NX Unit that is the farthest from the PROFINET Coupler
Unit. In this example, the IO power supply voltage of Unit (7) is found.
 Conditions
Assume that an IO power supply voltage of 24.00 VDC is supplied to the IO power supply terminals
on the PROFINET Coupler Unit.
 Procedure
1
Use the following formula to calculate the total current consumption from the IO power supply.
Total current consumption from the IO power supply =(1) + (2) + (3) + (4) + (5) + (6) + (7)
2
Find the IO power supply voltage and make sure that it is within the voltage specifications of the
IO circuits of the NX Units and the connected external devices.
IO power supply voltage at (7)
Design to Separate the IO Power Supply
If the IO power supply voltages of the connected external devices are different, connect an Additional
IO Power Supply Unit at the point where the IO power supply voltage changes and then perform similar
calculations to design a system that meets the power supply conditions. The same method is used to
separate the power supply systems. Connect an Additional IO Power Supply Unit at the point where the
NX-series PROFINET Coupler Unit User's Manual (W623)
that are supplied I/O power from the
PROFINET
Coupler Unit (total for (1)
to (7) = 4 A)
Coupler
NX Units
(1) (2) (2) (4) (5) (6)
To external To external
supply
devices devices
= IO power supply voltage on IO power supply terminals − (Voltage drop per Unit ×
Number of Units passed through)
= 24.00 V − 0.08 V × (7 − 1 Units)
= 23.52 V
5 Designing the Power Supply System
● Units that are supplied I/O
power from the Additional I/O
Power Supply Unit
Additional I/O Power Supply Unit
(7)
To external
devices
I/O power
supply
(24 VDC)
= 0 A + 1.5 A + 1.5 A + 0 A + 0 A + 0.5 A + 0.5 A
= 4 A
End Cover
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