Fan Control; Function Principle; Activating The Vsd / Pwm Fan - Siemens LMV37.4 Series Basic Documentation

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11 Fan control

11.1 Function principle

Optionally, the LMV37.4... system can be operated with a VSD or PWM fan. Control is
accomplished via a DC 0...10 V interface. For control of the fan's speed, a safety-
related speed feedback signal is required. With pneumatic air-fuel ratio control, the
speed feedback signal is not evaluated. To facilitate the use of fans with different speed
ranges, the fan's speed is standardized between 0...100%. If a fan control is not con-
nected, a power output and, alternatively, a fuel meter output are available (refer to
chapter Power output X74.3 and chapter Fuel meter input X75.1 / X75.2 ).
LMV...
5
4
3
2
1
Bild 332e/0409
Figure 45: Function principle of VSD

11.2 Activating the VSD / PWM fan

The VSD can be activated in any of the operating modes (P201).
No. Parameter
Activation of VSD / PWM fan
542 0 = inactive
1 = active
Note
For configuration of the analog output when the VSD is activated, refer to chapter
Power output X74.3 !
Basic documentation LMV37.4...
11 Fan control
5
Actual speed
4
3
2
1
Sensor disk
FU
Or
PWM
Sensor
L
CC1P7546en
01.12.2009