Protection Against Actuator Mixup; Proposal For Implementation - Siemens LMV37.4 Series Basic Documentation

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Building Technologies

11.9 Protection against actuator mixup

Mixup of actuators can be detected through appropriate mounting (using different
reference marks for the air and fuel actuator: Open/Close/0°/90°). With at least one of
the actuators, the reference mark not used must be blocked by a mechanical stop. Now,
if the actuator connections with the LMV37.4 have been interchanged, one of the
actuators cannot reach the reference mark, which is detected by the LMV37.4.
Protection against mixup is a question of burner application and must be ensured by the
OEM.
Caution!
To be able to detect mixup of actuators, the burner manufacturers must ensure
that the 2 actuators use opposing reference points. One of the actuators uses
the OPEN reference, the other the CLOSED reference. Approach of the
reference point not used must be blocked with at least one of the actuators!

11.9.1 Proposal for implementation


Parameterize referencing of the air damper in the CLOSED position

Parameterize referencing of the fuel damper in the OPEN position. Unnecessary
travel can be avoided by defining a home position of 90° for the fuel damper

Mechanical stop at the air damper in the range between 90° and 108.5°, and / or
mechanical stop at the fuel damper in the range between 0° and -5.6°
Referencing process

From any position in the working range (0...90°), but typically from the home
position, the air damper travels to the -7.7° position and back again to the home
position

From any position in the working range (0...90°), but typically from the home
position, the fuel damper travels to the 110.6° position and back again to the home
position
Process in the event of mixup

The fuel damper (fitted in place of the air damper) travels to the -7.7° position and
back again to the home position

The air damper (fitted in place of the gas damper) tries to travel to the 110.6°
position, but is prevented from doing so by the mechanical stop. This is
unsuccessful travel and identified as mixup
Basic documentation LMV37.4...
11 Actuators X53 / X54
CC1P7546en
17.12.2018