Special Features; Program Stop - Siemens LMV50 Series Manual

Outside the
operating position
Operating position
modulating
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multistage
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In the phases where the actuators are driven to 1 of the special positions (home,
prepurge, ignition or postpurge position), there is no continuous position check. To
make possible the change to the next phase, the required position must be reached. To
travel to the required position, the maximum time available is 35 seconds or 20% longer
than the time parameterized for TmeNoFlame. If the required position is not reached
within this maximum period of time, safety shutdown is initiated ↑ actuator overload
protection. In phases during which the damper does not move, the position is
continuously checked. If there are deviations from the required position, adjustment
attempts are made for which the ↑ dynamic safety time of fuel-air ratio control is used.
The position checkback signal delivered by the actuators is evaluated only when the
actuators do not travel, thus making possible precise position measurements.
To ensure that the actuators are not out of control of the LMV5 for longer periods of
time, longer movements are subdivided into traveling steps of 1.2 seconds. After each
step, the required position must be reached.
The target position is considered to be reached when the actuator has traveled to a
band width of ° Pos. tolerance value (neutral band).
If the actual position does not agree with the required position, readjustments are
made, whereby the ↑ dynamic safety time of fuel-air ratio control is applied.
In multistage operation, the actuators are monitored at stationary points. The actuators
must reach these points within the calculated period of time, whereby the ↑ dynamic
safety time of fuel-air ratio control is applied.
Additional position checks are made during the actuators' travel to find out if the
actuators do not move, or if they travel in the wrong direction.

6.6 Special features

6.6.1 Program stop

To facilitate burner startup, startup and shutdown can be stopped in several phases.
If a program stop is active, the special positions (prepurge, ignition and postpurge
position) can be set in the respective phase.
If a program stop has been activated, it remains active until manual deactivation takes
place (even after Power-off).
Parameter ProgramStop (deactivated / 24 PrePurgP / 32 PreP FGR /
36 IgnitPos / 44 Interv 1 / 52 Interv 2 / 72 PostPPos / 76 PostPFGR)
Basic Documentation LMV5...
6 Fuel-air ratio control (FARC)
CC1P7550en
22.05.2018