Table of Contents
Advertisement
Programming
Inverse regulation
Normal regulation means that the motor speed is
increased when the reference/setpoint is greater than the
feedback signal. If it is necessary to run inverse regulation,
in which the speed is reduced when the reference/setpoint
is greater than the feedback signal, parameter 437 PID
3
3
normal/inverse control must be programmed at Inverted .
Anti Windup
In the factory the process regulator is preset with an active
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.
Starting conditions
In some applications the optimal setting of the process
regulator will mean that a relatively 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 activated.
This is done by programming a start frequency in
parameter 439 Process PID start frequency.
3.5.5 Handling of Feedback
Feedback handling is depicted in this flowchart.
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.
Illustration 3.24
437
Process PID Normal/inverse control
Value:
Normal (NORMAL)
Inverse (INVERSE)
Function:
It is possible to choose whether the process regulator is to
increase/reduce the output frequency if there is a
58
®
VLT
DriveMotor FCM Series
difference between the reference signal and the feedback
signal.
Used together with Process, closed loop mode (parameter
100).
Description of choice:
If the FC motor is to reduce the output frequency in case
the feedback signal increases, select [0] Normal. If the FC
motor is to increase the output frequency in case the
feedback signal increases, select [1] Inverse.
438
Value:
Disable (DISABLE)
Enable (ENABLE)
Function:
It is possible to select whether the process regulator is to
continue regulating on an error even if it is not possible to
increase/reduce the output frequency. Used together with
Process, closed loop mode (parameter 100).
Description of choice:
The factory setting is [1] Enable, which means that the
integration link is adjusted in relation to the actual output
frequency if either the current limit or the max./ min.
frequency has been reached. The process regulator will not
engage again until either the error is zero or its sign has
changed.
Select [0] Disable if the integrator is to continue integrating
on an error, even if it is not possible to remove the fault
by such regulation.
439
Value:
f
MIN
parameter 201
Function:
When the start signal comes, the FC motor will react in the
form of Speed, open loop mode following the ramp. Only
when the programmed start frequency has been obtained,
will it change over to Process, closed loop mode. In
addition, it is possible to set a frequency that corresponds
to the speed at which the process normally runs, which
will enable the required process conditions to be reached
sooner.
Used together with Process, closed loop mode (parameter
100).
Description of choice:
Set the required start frequency.
440
[0]
Value:
[1]
0.00 (OFF)-10.00
0.01
®
MG03BA02 - VLT
is a registered Danfoss trademark
Process PID anti windup
Process PID start frequency
-f
(parameter 201 and 202)
MAX
Process PID proportional gain
[0]
[1]
[X.X]
[0-1000]
[1]
Advertisement
Table of Contents
