Siemens LMV37.400A2 - Fan Control Systems; Fan Control Function Principle; Activating VSD; PWM Fan

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Building Technologies Basic documentation LMV37.4... CC1P7546en
HVAC Products 11 Fan control 01.12.2009
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...
Bild 332e /04 09
X64
VSD X74
M
FU
Sensor L
Sensor disk
Actual speed
PWM
Or
4
5
3
2
1
4
5
3
2
1
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
542
Activation of VSD / PWM fan
0 = inactive
1 = active
&
Note
For configuration of the analog output when the VSD is activated, refer to chapter
Power output X74.3!