Fan Monitoring In The Fan Subassemblies - Siemens SIMATIC S7-400 Reference Manual

Cable duct and fan subassemblies

9.2 Fan monitoring in the fan subassemblies

9.2 Fan monitoring in the fan subassemblies
LEDs
The three red LEDs of the fan subassembly are assigned to the individual fans. From left to
right, these are:
F1 - for fan 1
F2 - for fan 2
F3 - for fan 3
Fans
The fans have a redundant design. The fan subassembly continues to function even if one fan
fails.
Fan monitoring
The function of the fans is controlled by means of speed monitoring. If the speed of a fan drops
below the limit speed of 1750 rpm, the LED assigned to it lights up. In addition, the relay K1
drops out.
If the speed of a second fan drops below the limit speed, the LED assigned to it lights up; in
addition, the relay K2 drops out.
The following table is the function table for the fan monitoring.
Table 9-1
Fan1
Example of a message concept
You can check the fault-free functioning of the fan subassembly using digital inputs.
378
Function of fan monitoring
Fan2 Fan3
- -
- -
- +
+ -
- +
+ -
+ +
+ +
-* -*
+ Fan in operation or relay picked up
- Fan failed or relay dropped out
D LED is dark
H LED lights up
* At power off
LED F1 LED F2
- H
+ H
- H
- D
+ H
+ D
- D
+ D
-* D* D*
Reference Manual, Ausgabe 11/2016, A5E00850736-08
LED F3 Relay K1
H H
H D
D H
H H
D D
H D
D H
D D
D*
S7-400 Automation System Module Data
Relay K2
- -
- -
- -
- -
- +
- +
- +
+ +
-* -*