8 Actuator and feedback
Positioner DC 6-06
49
8.1
Calibrating the actuator
Before the control unit can compute the exact position of the control path, reference values
must tell it the relationship between the control path measured value and the position of the
actuator. These reference values correspond to the control unit's measured values at the
minimum and maximum position of the actuators. In the case of actuators with digital
feedback, the reference signal must also be measured.
Actuator calibration must be carried out for every control unit with its
associated actuator, otherwise component tolerances of both the actuator
and the control unit will affect control quality and especially the
compliance of the limiting functions. Actuators must be re-calibrated if
either the actuator or the control unit have been replaced.
Calibration can be carried out automatically or manually. The actuators must be capable of
reaching the minimum and maximum position in all cases. Only if the actuator is calibrated
to its full stroke can exact positioning be expected subsequently. The greater the difference
between the measured values at the 0 % and the 100 % positions, the more accurately the
set position can be controlled. The actuator should therefore be calibrated without its
linkage if possible.
Calibration determines the 0 % and 100 % positions of the actuator. The
subsequent approach to these positions and to all intermediate values is
initiated by the external setpoint in the range 0..100 %. The 0 % position is
approached with the 0 % setpoint, the 100 % actuator position is
approached with the 100 % setpoint. If the external setpoint and the
actuator setpoint are not identical, an adaptation curve must be interposed
(
4.2 Determining the actuator setpoint).
8.1.1
Manual calibration
Manual calibration is performed similarly to the calibration of analogue inputs.
The actuator must be moved to the minimum and maximum position, with the control
unit's measured value
3950
Feedback
being entered in the parameter
1950
FeedbackRef_0%
for the minimum position and in the parameter
1951
FeedbackRef_100%
for the maximum position.
Note
Note
Summary of Contents for PANDAROS DC 6-06
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