Configuring
4.8 Example: Selecting a cabinet
S7-300, CPU 31xC and CPU 31x: Installation
4-14
Operating Instructions, Edition 08/2004, A5E00105492-05
4.8
Example: Selecting a cabinet
Introduction
The sample below clearly shows the maximum permitted ambient temperature at a specific
power loss for different cabinet designs.
Installation
The following device configuration should be installed in a cabinet:
•
Central unit, 150 W
•
Expansion modules, each with 150 W
•
Load power supply under full load, 200 W
This results in an accumulated power loss of 650 W.
Power loss dissipated
The diagram in the figure below shows guide values for the permitted ambient temperature
of a cabinet with the dimensions 600 mm x 600 mm x 2,000 mm, based on the accumulated
power loss. These values only apply if you maintain the specified assembly and clearance
dimensions for racks (rails).
200
400
600
800
1000
1200
1400
Power loss in W
20
30
40
50
60
Ambient temperature in °C
1
2
3
1
Trend
shows you the following cabinet type
(1)
Closed cabinet with heat exchanger (heat exchanger size 11/6
(920 mm x 460 mm x 111 mm)
(2)
Cabinet with through-ventilation by natural convection
(3)
Closed cabinet with natural convection and forced convection by equipment fans