Prioritization Of Power Sources; Emergency Operation With Several Load Controllers; Manual Control - Siemens LMV37.4 Series Basic Documentation

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8.7 Prioritization of power sources

To simplify configuration of the system, the power source need not be selected. The
system automatically detects the available power sources and selects them. If several
sources are used, they are selected according to the following priorities:
Parameter 942 Priority
1 highest
1 2
2 3
3 4
4 5
5 6 lowest
The active power source can be read out via parameter 942.

8.7.1 Emergency operation with several load controllers

By making use of the prioritization described above, it is also possible to implement
emergency operation. Should the building automation and control system fail (provided
parameter 148 is set to undefined (--)), the unit switches automatically over to the exter-
nal load controller.
A load controller via analogue input or, if existing via contacts can be connected.

8.7.2 Manual control

If the external load controller via analogue input or via contacts is not used, a simple
manual output adjustment via switch can be implemented by cutting the connection to
the load controller for switching from automatic to manual operation. In that case, the
system switches to the external load controller via contact. An OPEN / CLOSED switch
or stage 2 / stage 3 can then be connected to its terminals.
Basic documentation LMV37.4...
8 Connection to load controllers
Active power source
Chapter Controller-on-contact X5-03, terminal 1
When the input is activated, the other output
sources is assessed according to their priorities.
When the input is deactivated, the burner is off
Chapter Output with curve settings
Chapter Manual output
Chapter Load controller via the building automa-
tion system
Chapter External load controller via analog input
X64 terminal 1 / terminal 2
Chapter External load controller via contacts X5-
03, terminal 2 / terminal 3
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CC1P7546en
01.12.2009