User`s manual

Installation Calculating heat generation of programmable controller
9 – 8
Average power consumption due to voltage drop in the output section of the output
module
W
OUT
= I
OUT
x V
drop
x n x O
S
[W]
I
OUT
: Output current (Current in actual use)
V
drop
: Voltage drop in each output module
n: Number of outputs
O
S
: Simultaneous ON rate (specifies how many outputs are switched on simultaneously,
O
S
= 1: all outputs simultaneously ON)
Average power consumption of the input section of the input module
W
IN
= I
IN
x V
IN
x n x I
S
[W]
I
IN
: Input current (Effective value for AC)
V
IN
: Input voltage (Voltage in actual use)
n: Number of input points
I
S
: Simultaneous ON rate (specifies how many inputs are switched on simultaneously,
I
S
= 1: all inputs simultaneously ON)
Power consumption of the external power supply section of the intelligent function
module
The calculation formula for the power consumption of intelligent function modules is as follows:
W
S
= I
5V
x 5 V + I
24V
x 24 V+ I
100V
x 100 V [W]
Overall power consumption of the programmable controller system
The total of the power consumption values calculated for each block becomes the power con-
sumption of the overall sequencer system:
W = W
PW
+ W
5V
+ W
24V
+ W
OUT
+ W
IN
+ W
S
[W]
From this overall power consumption (W), calculate the heating value and a rise in ambient tem-
perature inside the panel. The outline of the calculation formula for a rise in ambient temperature
inside the panel is shown below.
T = W / (U x A) [°C]
W: Power consumption of overall sequencer system
A: Surface area inside the panel (m
2
)
U: 6, when the ambient temperature inside the panel is uniformed by a fan
4, when air inside the panel is not circulated
NOTES
If the temperature inside the panel has exceeded the specified range (55 °C), it is recom-
mended to install a fan, a heat exchanger or chiller to the panel to lower the temperature.
Fans should always be equipped with appropriate dust filters and sufficient protection.