NB!
Parameters 417-421 are only used, if in
parameter 100
Configuration
the selection
made is
Speed regulation, closed loop
[1].
417
Speed PID proportional gain
(SPEED PROP GAIN)
Value:
0.000 (OFF) - 1.000
0.010
Function:
Proportional gain indicates how many times the fault
(deviation between the feedback signal and the set-
point) is to be amplified.
Description of choice:
Quick regulation is obtained at high amplification, but
if the amplification is too high, the process may be-
come unstable in the case of overshooting.
418
Speed PID integral time
(SPEED int. time)
Value:
20.00 - 999.99 ms (1000 = OFF)
100 ms
Function:
The integral time determines how long the PID regu-
lator takes to correct the error. The greater the error,
the quicker the integrator frequency contribution will
increase. The integral time is the time the integrator
needs to achieve the same change as the proportional
amplification.
Description of choice:
Quick regulation is obtained through a short integral
time. However, if this time is too short, it can make the
process unstable. If the integral time is long, major de-
viations from the required reference may occur, since
the process regulator will take long to regulate if an
error has occurred.
419
Speed PID differential time
(SPEED diff. time)
Value:
0.00 (OFF) - 200.00 ms
20.00 ms
Function:
The differentiator does not react to a constant error. It
only makes a contribution when the error changes.
The quicker the error changes, the stronger the gain
from the differentiator will be. The contribution is pro-
portional to the speed at which errors change.
Description of choice:
Quick control is obtained by a long differential time.
However, if this time is too long, it can make the proc-
ess unstable. When the differential time is 0 ms, the D-
function is not active.
420
Speed PID D- gain limit
(SPEED D-GAIN LIM)
Value:
5.0 - 50.0
5.0
Function:
It is possible to set a limit for the gain provided by the
differentiator. Since the D-gain increases at higher fre-
quencies, limiting the gain may be useful. This enables
obtaining a pure D-gain at low frequencies and a con-
stant D-gain at higher frequencies.
Description of choice:
Select the required gain limit.
421
Speed PID lowpass filter time
(speed filt. time)
Value:
20 - 500 ms
100 ms
Function:
Noise in the feedback signal is dampened by a first
order lowpass filter to reduce the noise's impact on the
regulation. This might be an advantage, e.g. if there is
a great amount of noise on the signal. See drawing.
= factory setting, () = display text, [] = value for use in communication via serial communication port
100
MG.27.E2.02 - VLT is a registered Danfoss trademark
