Danfoss VLT 2800 Series General Information

439 Process PID start frequency
(PROC START VALUE)
Value:
f
MIN
- f
MAX
(pa-
rameter
201/202)
Par. 201 Output frequency, low
limit, f
MIN
Function:
When the start signal comes, the adjustable frequency
drive will react in the form of Open loop and will not
change to Closed loop until the programmed start fre-
quency is reached. This makes it 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.
Description of choice:
Set the required start frequency.
NOTE
If the adjustable frequency drive is running
a the current limit before the required start
frequency is obtained, the process regu-
lator will not be activated. For the regulator
to be activated anyway, the start frequen-
cy must be lower to the required output
frequency. This can be done during oper-
ation.
440 Proces PID proportioanl gain
(PROC. PROP. GAIN)
Value:
0.0 - 10.00
0.01
Function:
The proportional gain indicates the number of times
the deviation between the setpoint and the feedback
signal is to be applied.
Description of choice:
Quick regulation is obtained by a high gain, but if the
gain is too high, the process may become unstable due
to overshoot.
441 Process PID integration time
(PROC. INTEGR. T.)
Value:
0.01 - 9999.99 (OFF)
OFF
Function:
The integrator provides an increasing gain at a con-
stant error between the reference/setpoint and the
feedback signal. The greater the error, the quicker the
integrator frequency contribution will increase.The in-
tegral time is the time needed by the integrator to make
the same change as the proportional gain.
Description of choice:
Quick regulation is obtained at a short integral time.
However, this time may become too short, which can
make the process unstable due to overswing. If the in-
tegral time is long, major deviations from the required
setpoint may occur, since the process regulator will
take a long time to regulate in relation to a given error.
442 Process PID differentiation time
(PROC. DIFF. time)
Value:
0.00 (OFF) - 10.00 sec.
0.00 sec.
Function:
The differentiator does not react to a constant error. It
only makes a gain when an error changes. The quicker
the deviation changes, the stronger the gain from the
differentiator. The gain is proportional to the speed at
which the deviation changes.
Description of choice:
Quick regulation is obtained with a long differentiation
time. However, this time may become too long, which
can make the process unstable due to overswing.
443 Process PID diff. gain limit
(PROC. DIFF.GAIN)
Value:
5.0 - 50.0
5.0
VLT
®
2800 Series
= factory setting, () = display text, [] = value for use in communication via serial communication port
MG.27.A2.22 - VLT
®
is a registered Danfoss trademark 75
Programming

Danfoss VLT 2800 Series Specifications

General

Brand	Danfoss
Model	VLT 2800 Series
Category	DC Drives
Language	English