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Siemens Building Technologies
Basic Documentation LMV5...
CC1P7550en
HVAC Products
18 Addendum 3: Variable speed drive (VSD) module
13.08.2004
To acquire the amount of fuel consumed, up to 2 fuel meters can be connected. As-
signment to the type of fuel is fixed.
To adapt to different types of fuel meters, assignment of the number of pulses and the
resulting fuel throughput must be parameterized.
Type of sensor:
inductive sensor to DIN 19234 (Namur) or
open collector (pn) with U
CEsat
< 4 V, U
CEmin
> DC 15 V or
Reed contact
Frequency:
≤
300 Hz
Pulses / l or gal, m
3
:
≤
9999.9999 (to be parameterized)
Pulses / ft
3
:
≤
999.99999 (to be parameterized)
Power supply:
DC 10 V, max. 15 mA
Switching current:
> 10 mA
18.1.2 Configuration of VSD
The VSD must be configured in accordance with the type of motor connected.
The times set for the acceleration and deceleration ramps must be shorter than the
times of the ramps parameterized for the LMV5x.2... with electronic fuel / air ratio con-
trol.
Example:
Ramp of 10 seconds
⇒
VSD ramps to be set to 7 seconds.
The motor must be able to follow the parameterized VSD ramp.
If this is not observed, the predefined speeds will not be reached within the respective
periods of time.
The configuration of the current / voltage interfaces of the VSD must be in accordance
with the configuration of the LMV5x.2... VSD module.
The minimum output frequency of the VSD must be set to 0 Hz. To ensure that the fan
motor will reach the required speed under all operating conditions, the VSD during con-
figuration will be controlled with a maximum of only 95 % of the positioning signal. If the
burner’s rated capacity calls for full fan speed, the maximum output frequency must be
set to 105.2 % of mains frequency.
Fuel meter
Fuel meter input
X71 / X72