Basic Documentation
42 / 46
Siemens VAV compact controller KNX/PL-Link G..B181.1E/KN CE1P3547en
Smart Infrastructure 2021-10-25
9.5.5 Adaptive positioning
9.5.5.1 Function
For VAV boxes and air dampers with an opening range smaller than 0...90°, the
position setpoint and feedback signal can be adapted to 0...100%.
• Adaptive positioning off: Position control / feedback relative to 0°…90°,
→Example: 0° → 0%, 18° → 20%, 81° → 90% etc.
• Adaptive positioning on: Position control / feedback relative to the mechanical
lower / upper endstops which are determined in an adaptation run.
→Example: The lower endstop is at 15° and the upper endstop is at 60°
15° → 0%, 45° → 66%, 60° → 100% etc.
9.5.5.2 Activation and deactivation
• Immediately after changing the parameter “Adaptive positioning” from off to
on, an adaptation run is performed. During the adaptation run, the actuator
drives to both mechanical end stops and stores these positions persistently as
0% and 100% reference points. Cf. diagram below for a detailed description.
Important: Adaptation must not be activated while a device jam is present!
• Adaptive positioning can be (de-)activated with the service interface (ACS931 /
ACS941 / AST20) or over the bus.
• If adaptive positioning is deactivated before the adaptation run has finished,
the adaptation run will stop immediately, and no end stops will be stored.
• In case of a power reset during the adaptation run, the adaptation run will
restart automatically after the power supply has been restored.
• To trigger the adaptation run again the adaptive positioning must be turned off
and on again.
• A manual gear disengagement of less than 20 seconds doesn’t impact the
adaptation run or its result.
A. Adaptive positioning is set to on. Actuator drives to
the counter-clockwise (CCW) endstop.
B. CCW endstop is reached.
C. If the position remains constant for ca. 10
seconds, it is stored non-volatile. The actuator
then drives to the clockwise (CW) endstop.
D. CW endstop is reached.
E. If the position remains constant for ca. 10
seconds, it is stored non-volatile. The actuator
now follows the adapted setpoint.
Example: Stop screw set at
~75% of the full range
Note: If the adaptation run starts close to the CW endstop, it can take up to 5.5 minutes
for completion (2x 150s + waiting times in the endstops).