Designing The I/O Power Supply From The Nx Bus - Omron NX1P2 Series Hardware User Manual

4 Designing the Power Supply System
4-3-2

Designing the I/O Power Supply from the NX Bus

Procedure for Designing the I/O Power Supply
The procedure is explained under the precondition that an Additional I/O Power Supply Unit is con-
nected to the right side of the CPU Unit because an NX Unit that requires the power supply from NX
bus is mounted on the CPU Rack.
Make sure that the following design conditions are met when you design the I/O power supply from the
NX bus.
• The total current consumption from the I/O power supply must not exceed the maximum I/O power
supply current of the Unit that supplies the I/O power.
• The voltage drop in the I/O power supply must be within the voltage specifications of the I/O circuits
of the NX Units and the connected external devices.
Use the following procedure to design the I/O power supply.
1
Calculate the total current consumption from the I/O power supply of the NX Units that are con-
nected to the CPU Unit and the CPU Unit, and calculate the voltage drop in the I/O power sup-
ply.
2
Add an Additional I/O Power Supply Unit in either of the following cases, a) or b). Add the Addi-
tional I/O Power Supply Unit to the right of the NX Unit for which both a) and b) do not apply.
a) The total current consumption for the I/O power supply exceeds 4 A.
b) Voltage drop in the I/O power supply causes the voltage of the I/O power supply to go be-
low the voltage specifications of the I/O circuits of the NX Units or the connected external
devices.
3
Calculate the voltage drop in the I/O power supply after the Additional I/O Power Supply Unit
and the total current consumption from the I/O power supply that is required by the Additional
I/O Power Supply Unit and by the NX Units that are connected after the Additional I/O Power
Supply Unit. Add another Additional I/O Power Supply Unit in either of the following cases, a)
or b). Add the Additional I/O Power Supply Unit to the right of the NX Unit for which both a) and
b) do not apply.
a) The total current consumption for the I/O power supply exceeds the I/O power supply ca-
pacity of the Additional I/O Power Supply Unit.
b) Voltage drop in the I/O power supply causes the voltage of the I/O power supply to go be-
low the voltage specifications of the I/O circuits of the NX Units or the connected external
devices.
4
Repeat step 3 until the design conditions for the I/O power supply are met.
4-14
NX-series NX1P2 CPU Unit Hardware User's Manual (W578)