Mitsubishi Q2ACPU User Manual

19.
19 - 8
LOADING AND INSTALLATION
19.3 Calculation of Heat Generated by the PLC
The operating ambient temperature in the panel where the PLC is stored must be kept
55 or less.For heat dissipation design of the panel, it is necessary to know the average
power consumption (heat generation) of the devices and machinery stored inside.In this
section, a method to obtain the average power consumption of the PLC system is
explained.
Calculate the temperature rise inside the panel from the power consumption.
The power consuming parts of the PLC may be roughly classified into the following blocks:
(1) Power consumption by power supply module
The power conversion efficiency of the power supply module is about 70%, and 30%
is consumed as heat generated, thus, 3/7 of the output power is the power
consumption.Therefore, the calculation formula is:
(2) Total power consumption of 5VDC logic circuits of modules
The 5VDC output circuit power of the power supply module is regarded as the power
consumption of each module.
W
5V=I5V 5 (W)
I
5V : Current consumption of 5VDC logic ladder circuit of each module
I
15V : Current consumption of 15VDC external power supply part of special function
module
I
24V : Average current consumption of 24VDC power supply for output module's
internal consumption
(Current consumption equivalent to the points simultaneously ON)
...... Not applicable to a system where 24VDC is supplied externally and a
power supply module with no 24VDC output is used.
Average Power Consumption
Wpw= {(I5V 5)+(I15V 15)+(I24V 24)} (W)
7
3

Mitsubishi Q2ACPU Specifications

General

Brand	Mitsubishi
Model	Q2ACPU
Category	Controller
Language	English