Setting The Minimum Power Control Step (Dead Band) (P123) In Modulating Mode Via Analog Input Signal X65 - Siemens LME7 Series Basic Documentation

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Building Technologies Division
Infrastructure & Cities Sector
21.7 Setting the minimum power control step
(dead band) (P123) in modulating mode via
analog input signal X65
The minimum power control step must be greater than or equal to the percentage
proportion of the maximum resolution of the entire modulation range (protection against
hunting).
Calculation:
100% x maximum resolution
---------------------------------------- = minimum power control step
Modulation range
Example: Actuator: 0...90° working range, resolution approx. 0.5°
Modulation range: Low-fire position = 20°, high-fire position = 70°
Modulation range in angular degree
Calculation: 70° - 20° = 50 °
Minimum power control step
Calculation:
100% x 0.5°
----------------- = 1%
50°
Note:
If the value set for parameter P123 is too small, the actuator oscillates about the
setpoint, leading to more running cycles, increased switching frequency and more wear
and tear.
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29.11.2011