Handling Of Feedback - Danfoss VLT FCD 303 Operating Instructions Manual

In the factory the process regulator is preset with
an acti v e anti windup function. This function means
that when either a frequency limit, a current limit or
a voltage limit is reached, the integrator is initialised
at a frequency corresponding to the present output
frequency. This is a means of avoiding the integration
of a variance between the reference and the process's
actual mode that cannot be deregulated by means of
a change of speed. This function can be deselected
in parameter 438 Process PID anti windup.

Handling of feedback

Feedback handling is depicted in this flowchart.
= factory setting. () = display text [] = value for use in communication via serial communication port
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VLT FCD Series
Starting conditions
In some applications the optimal setting of the
process regulator will mean that a relati v ely long
period of time will pass before the required process
condition is achieved. In these applications it can
be a good idea to define an output frequency to
which the frequency converter must run the motor
before the process regulator is acti v ated. This is
done by programming a start frequency in parameter
439 Process PID start frequency.
The flowchart shows which parameters can affect the
handling of feedback and how. A choice can be made
between voltage, current and pulse feedback signals.
MG.04.B7.02 - VLT is a registered Danfoss trademark