Chapter 9 Installation and Wiring
(e) Input average power consumption of input module
(power consumption of simultaneous On point)
• Win = lin X E X input point X simultaneous On rate (W)
Iin: input current (root mean square value in case of AC) (A)
E
: input voltage (actually used voltage) (V)
(f) Power consumption of special module power assembly
• WS = I5V X 5 + I24V X 24 + I100V X 100 (W)
The sum of power consumption calculated by each block is the power consumption of the
entire PLC system.
•
W = WPW + W5V + W24V + Wout + Win + Ws (W)
Calculate the heats according to the entire power consumption(W) and review the
temperature increase within the control panel.
The calculation of temperature rise within the control panel is displayed as follows.
T = W / UA [°C]
W : power consumption of the entire PLC system (the above calculated value)
A : surface area of control panel [m
2
]
U : if equalizing the temperature of the control panel by using a fan and others - - - 6
If the air inside the panel is not ventilated - - - - - - - - - - 4
If installing the PLC in an air-tight control panel, it needs heat-protective(control) design
considering the heat from the PLC as well as other devices. If ventilating by vent or fan, inflow of
dust or gas may affect the performance of the PLC system.