Calculating Power Consumption; Total Power Consumption Of The Controller (W_Gross); Basic I/O Unit Power Consumption (W_Io_Onoff) - Omron NJ501-1 Series User Manual

3 Configuration Units

Calculating Power Consumption

The ambient operating temperature at the control panel where an NJ-series Controller is mounted must
be no higher than 55C.
This section describes how to calculate the power consumption of a CPU Rack or Expansion Rack for
use in the thermal design of the control panel.
 Calculating Power Consumption
Use the following equation to calculate the average power consumption (W) of an NJ-series CPU
Rack.
W = W_Gross + W_IO_ONOFF
 Total Power Consumption of the Controller (W_Gross)
The Controller power consumption is calculated based on the total power consumption of the Units
that are mounted in the CPU Unit and the power conversion rate of the Power Supply Unit.
W_Gross = W_unit  
• W_unit:
Total power consumption of Units mounted to the CPU Rack. For details on the current consump-
tion and voltage of individual Units, refer to CJ-series Configuration Units on page 2-11.
• :
Power Supply Unit power conversion rate.
The rate is 70% for the NJ Series, so use "0.7" in the calculation.
 Basic I/O Unit Power Consumption (W_IO_ONOFF)
The Basic I/O Unit power consumption is the total consumption for the Input Units and the Output
Units.
• Input Units
Rated input voltage  Input current  Number of input points
• Output Units
Residual voltage  Maximum load current  Number of output points
Note For a CJ-series Basic I/O Unit with transistor outputs, use a residual voltage of 0.1 V in the calculation. For a
CJ-series Basic I/O Unit with relay or triac outputs, use a residual voltage of 0 V in the calculation.
3-18
Basic I/O Unit power consumption
(Power supplied to Basic I/O Units from Units
other than the Power Supply Unit.)
Total power consumption of the Controller
(Power supplied to the Controller from the Power Supply Unit and loss in Power Supply Unit.)
NJ-series CPU Unit Hardware User's Manual (W500)