Siemens S7-400 ユーザーズマニュアル

9-2

S7-400, M7-400 Programmable Controllers Module Specifications

A5E00069467-07

In this section, you will find out how to monitor the fans. 
There is a signaling concept example at the end of the section.

The three red LEDs are assigned to the individual fans. From left to right, these
are:

F1 – for fan 1

F2 – for fan 2

F3 – for fan 3

The fans have a redundant design. The fan subassembly continues to function
even if one fan fails.

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

Function of Fan Monitoring

–

–

–

L

L

L

–

–

–

–

+

L

L

D

–

–

–

+

–

L

D

L

–

–

+

–

–

D

L

L

–

–

–

+

+

L

D

D

–

+

+

–

+

D

L

D

–

+

+

+

–

D

D

L

–

+

+

+

+

D

D

D

+

+

–*

–*

–*

D*

D*

D*

–*

–*

+

Fan in operation or relay picked up

–

Fan failed or relay dropped out

D

LEDs dark

L

LEDs lit

*

Power off