You can cause the power supply to be cut off after the failure of at least two fans by using the
relay K2. For example, you can use an intermediate contactor to interrupt the mains.
The relay contacts are labeled as follows:
Relay K1: No. 1 to 3
Relay K2: No. 4 to 6
The following diagram explains the circuit in the fan subassembly when all fans are functioning.
6
5
4
3
2
1
L+
24 V
K1
K2
... to the digital input module
Evaluation
(digital input module)
Evaluation
(digital input module)
to the power supply module
Status: All fans operating
to the mains
in the fan assembly
... to the monitor
... to the monitor
Figure 9-1
Example of a message concept
Cable duct and fan subassemblies
9.2 Fan monitoring in the fan subassemblies
S7-400 Automation System Module Data
Reference Manual, Ausgabe 11/2016, A5E00850736-08
379