Connection To Load Controllers; Load Controller On Contact X5-03, Pin 1; External Load Controller Via Contacts X5-03, Pin 2 / Pin 3 - Siemens LMV27.100x2 Basic Documentation

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Connection to load controllers

The LMV27 can be connected to different load controllers. Heat request and the
required burner output are determined in accordance with the priorities of the different
load sources.

9.1 Load controller on contact X5-03, pin 1

This contact is given priority over all load controller sources. A heat request can only be
made when this contact is closed. The contact is safety-related and can also be used in
connection with load controllers featuring an integrated Temperature limiter function.
9.2 External load controller via contacts X5-03, pin
2 / pin 3
The heat request is delivered via pin 1. Modulation of burner output is effected via pin 2
and 3. Here, a differentiation is made between modulating and multistage operation
(refer to chapter Selection of operating mode).
Modulating operation X5-03 (OPEN pin 3 / CLOSE pin 2)
If input Open is active, the burner's output is increased. If input Close is active, the
burner's output is decreased. If none of the inputs is active, the burner's output is not
changed.
The rate of integration is 32 seconds for changing the output from low-fire (20%) to high-
fire (100%) or vice versa (parameter 544), that means a burner output from 100% to
20%.
Output integration always takes place in the operating position.
200 ms is the shortest positioning step that is securely detected.
Load controller (LR) (ON / OFF)
Figure 59: Modulating operation X5-03
No. Parameter
544 Ramp modulating
Minimum positioning step
To prevent the actuators from making unnecessary position changes when the
preselected target output varies, a minimum positioning step can be set. In that case,
the LMV27 changes the output only when the preselected target output exceeds the
minimum positioning step. This minimum positioning step is only used in modulating
operation.
No. Parameter
123.2 Minimum output positioning step: Output of external load controller contacts
Basic Documentation LMV27...
9 Connection to load controllers
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17.12.2018