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Building Technologies   Basic documentation LMV37.4...  CC1P7546en 
  11 Actuators X53 / X54  17.12.2018 
11.6  Changing the error detection band for 
monitoring the actuator positions 
 
The error detection band can be changed via parameter 606. A change is to be 
made only when using SQN13.17 or SQN14.17 actuators which, due to their 
mechanical design, require greater tolerances. 
For these types of actuators, set parameter 606 to 2.2°.
 
 
No. Parameter 
606 
Tolerance limit of position monitoring (0.1°) 
Index 0 = fuel 
Index 1 = air 
 
Greatest position error where an error is securely detected  
 Error detection band: (parameter 606 -0.6°) up to parameter 606 
 
11.7 Forced travel 
 
There are errors in the actuators’ feedback unit which can only be detected in 
connection with position changes. To be able to also detect such errors when 
maintaining the same position for longer periods of time, travel is enforced when – for 
more than 50 minutes – an actuator moves no more than 2.8°. With forced travel, both 
actuators are driven 2.8° in the direction of smaller positioning angles and back again to 
the initial angular position. If a damper is less than 2.8° open, the actuator is driven in 
the direction of positive angles in order not to run against mechanical stops, if present. 
Forced travel lasts a total of 1 second. 
 
11.8 Detection of line interruptions 
 
The connecting line ensuring position feedback from the actuator to the LMV37.4 is 
monitored for interruptions, which means that position feedback cannot fail without being 
noticed. 
 
Error 
code 
Diagnostic 
code 
Meaning for the LMV37.4 
86 Bit 0 
Valency 1 
Line interruption fuel actuator 
87 Bit 0 
Valency 1 
Line interruption air actuator