Outside The Operating Position; Operating Position Modulating; Operating Position Multistage; Special Features - Siemens LMV51 Series Basic Documentation

Outside the
operating position
Operating position
modulating
Operating position
multistage

Program stop

Direction of rotation
of actuators
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HVAC Products
In the phases where the actuators are driven to one 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 TmeNoFlame parameterized. If the required position is not reached within
this maximum period of time, safety shutdown will be initiated ® actuator overload
protection.
In the phases where the damper does not move, the position is continuously checked.
If there are deviations from the required position, adjustment attempts are made where
the ® «Dynamic safety time 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 basic unit 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 required position is considered to be
reached when the actuator has traveled to a band width of ± 0.3°.
If the actual position does not agree with the required position, readjustments will be
made, whereby the ® dynamic safety time of the fuel / air ratio control system will be
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 the fuel / air ratio control system will be applied.
Additional position checks are made during the actuators' travel, in order to find out if
the actuators do not move, or if they travel in the wrong direction.

4.1.3 Special features

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)
The actuators' direction of rotation can be reversed, so that the direction of rotation can
be matched to the mounting method.
The direction of rotation must be selected before defining the ignition position and the
curvepoints. If that is not observed, these points must be deleted before the direction of
rotation is reversed. For that purpose, a special function called «Delete curves» is
offered on the menu for selecting the direction of rotation.
Parameter: 1 AirActuator (Standard / Reversed)
Parameter: 2 GasActuat(Oil) (Standard / Reversed)
Parameter: 3 OilActuator (Standard / Reversed)
Parameter: 4 AuxActuator (Standard / Reversed)
Basic Documentation LMV51...
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CC1P7550en
29.05.2002