Protection Against Mixup Of Actuator; Proposal For Implementation - Siemens LMV36.520A1 Basic Documentation

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Building Technologies Division
Infrastructure & Citiies Sector

12.9 Protection against mixup of actuator

Mixup of actuators can be detected through appropriate installation (using different
reference marks for the air and fuel actuator: OPEN / CLOSED / 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 basic unit have been interchanged, one
of the actuators cannot reach the reference mark, which is detected by the basic unit.
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 manufacturer 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!

12.9.1 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
Action 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
The above procedure to prevent mixup of actuators by using different reference
positions is only suited for 2 actuators. In the case of dual-fuel systems with 3 actuators,
it can be employed to prevent mixup of air actuator and fuel actuators OR to prevent
mixup of fuel actuators. With the LMV36..., the above procedure ensures protection
against mixup of air actuator and fuel actuators (different reference positions and
mechanical stops).
Note
It is recommended to color-code the actuators' assignment to the AGM60..., thus
preventing mixup of actuators by observing the respective color marks on the
AGM60... and the actuators' connectors.
Alternatively, protection against mixup of one of the actuators can also be ensured by
a coding pin on the AGM60...
Basic documentation LMV36...
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CC1P7544en
25.09.2013