Siemens Simatic S7-400 - Manual (Page 415)

Cable Duct and Fan Subassemblies
9-3
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Signaling Concept Example
You can check the fault-free functioning of the fan subassembly using digital inputs.
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...3
Relay K2: No. 4...6
The following diagram explains the circuit in the fan subassembly when all fans are
functioning.
6
5
4
3
2
1
L+ ... to the monitor
... to the monitor
... to the digital input module
24 V
... to the mains
... to the power supply module
... in the fan assembly
K1
K2
Evaluation
(digital input module)
Evaluation
(digital input module)
Status: All fans operating
Figure 9-1 Example of a Message Concept