Speed Supervision - Siemens LMV37.4 Series Basic Documentation

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12.9 Speed supervision

The fan's current speed is acquired by the LMV37.4... 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
0...0.5%
0.6...2%
2.1...10%
>10%
Error Diagnostic Meaning for the LMV37.4... system
code code
83 Bit 0 Lower control range limitation
Valency 1
Bit 1 Upper control range limitation
Valency 2...3
Bit 2 Interrupt shutdown due to electromagnetic interference
Valency 4...7
Bit 3 Curve too steep in terms of ramp speed
Valency 8
Bit 4 Interruption of speed signal
Valency 16
Bit 5 Quick shutdown due to excessive speed deviation
Valency 32
Basic documentation LMV37.4...
12 Fan control
Shutdown time
Speed reached  no shutdown
<8 s
<3 s
<1 s
CC1P7546en
20.09.2013