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Building Technologies Division Basic documentation LMV36... CC1P7544en
Infrastructure & Citiies Sector 13 Fan control 25.09.2013
13.9 Speed supervision
The fan’s current speed is acquired by the LMV36... and assessed from a safety point of
view. If the fan does not operate at the speed setpoint, speed control makes a corrective
action, trying to reach the setpoint. If it is not reached within a certain period of time,
safety shutdown is initiated. To ensure a high level of availability and safety, a number
of monitoring bands with different response times are defined.
It is possible to switch off speed supervision at standstill (no-load speed 0%) in standby
mode. This may be necessary if the fan rotates too much in standby mode due to a
chimney draft or if an extended ramp time is active with a PWM fan during the transition
from the postpurge speed to standstill.
No. Parameter
653 VSD standstill supervision in standby mode
0 = deactivate
1 = active
Speed deviation in % points Shutdown time
0…0.5% Speed reached no shutdown
0.6...2% <8 s
2.1...10% <3 s
>10% <1 s
Error
code
Diagnostic
code
Meaning for the LMV36... system
83 Bit 0
Valency 1
Lower control range limitation of control
Bit 1
Valency 2...3
Upper control range limitation of control
Bit 2
Valency 4...7
Interruption via disturbance pulses
Bit 3
Valency 8
Curve too steep in terms of ramp speed
Bit 4
Valency 16
Interruption of speed signal
Bit 5
Valency 32
Quick shutdown due to excessive speed deviation
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