Mitsubishi Electric MELCEC Q Series User Manual page 155

9. LOADING AND INSTALLATION
(3)
(4)
(5)
(6)
Total 24VDC average power consumption of the output module (power consumption
equivalent to the points simultaneously ON)
Average power of the 24VDC output circuit of the power supply module is the total
power consumption of each module.
W =I 24 Simultaneous ON ratio (W)
24V 24V
Total 24VDC average power consumption of the output module
(power consumption equivalent to the points simultaneously ON)
W =I V Output points
OUT OUT drop
I : Output current (current actually used) (A)
OUT
V : Voltage drop of each output module (V)
drop
Average power consumption of the input modules at the input part (power
consumption equivalent to the points simultaneously ON)
W =I E Input points
IN IN
I : Input current (effective value in the case of AC) (A)
IN
E : Input voltage (voltage for actual usage) (V)
Power consumption of the external power supply part of the special function module
W =I 15 + I 15 + I
S +15V -15V
The total of the power consumption calculated for each block as above is the power
consumption of the programmable controller system as a whole.
W=W + W + W
PW 5V 24V
Calculate the amount of heat generation and temperature rise inside the panel from
the total power consumption (W).
Simplified calculation formula to obtain temperature rise inside panel is shown next:
W
T= [ ]
UA
Power consumption of the programmable controller system as a whole (the value
W:
obtained above)
A: Inside surface area of the panel [m
U: When inside temperature of the panel is kept constant by a fan, etc............6
When the air inside the panel is not circulated .............................................4
POINT
When the temperature rise inside the panel exceeds the specified range, it is
recommended to lower the temperature inside the panel by installing a heat
exchanger to the panel.
If a conventional ventilation fan is used, it sucks dust along with the outside air,
which may affect the programmable controller, so care must be taken.
Simultaneous ON ratio (W)
Simultaneous ON ratio (W)
24(W)
24V
+ W + W + W (W)
OUT IN S
]
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