Danfoss FCM305 56 Instruction Manual page 79

Description of choice:
Set the required start frequency.
NOTE!
If the FCM 300 is running at the current limit before
the desired start frequency is obtained, the process
regulator will not be activated. For the regulator to
be activated anyway, the start frequency must be
lowered to the required output frequency. This can
be done during operation.
440 Process PID proportional gain
(PROC. PROP. GAIN)
Settings:
0.00 (OFF) - 10.00
0.3
H,I
0.01
Function:
The proportional gain indicates the number of times
the error between the set point and the feedback
signal is to be applied.
Used together with Process, closed loop mode
(parameter 100).
Description of choice:
Quick regulation is obtained by a high gain, but if the
gain is too high, the process may become unstable.
441 Process PID integral time
(PROC. INTEGR. T.)
Settings:
0.01 - 9999 sec. (OFF)
20 sec.
H,I
9999 sec.
Function:
The integrator provides an increasing gain at a
constant error between the set point and the
feedback signal. The greater the error, the quicker
the gain will increase. The integral time is the time
needed by the integrator to reach the same gain as
the proportional gain.
Used together with Process, closed loop mode
(parameter 100).
= General factory setting - also applying to spare part unit, H H H H H = HVAC setting, I I I I I = Industrial setting, ( ) = parameter
window text. [ ] = value for use in communication via serial communication port
MG.03.B6.2G - VLT is a registered Danfoss trademark
FCM 300 Series
Description of choice:
Quick regulation is obtained at a short integral time.
However, if this time is set too short, the process
can become unstable.
If the integral time is long, major deviations from the
required set point 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)
Settings:
0.00 (OFF) - 10.00 sec.
[0 - 1000]
0.00 sec.
[30]
[1]
Function:
The differentiator does not react to a constant error.
It only provides a gain when the error changes. The
quicker the error changes, the stronger the gain
from the differentiator.
The gain is proportional to the speed at which the
error changes.
Used together with Process, closed loop mode
(parameter 100).
Description of choice:
Fast regulation is obtained with a long differentiation
time. However, if this time is set too long, the
process can become unstable.
[1 - 999900]
443 Process PID diff. gain limit
[2000] (PROC. DIFF. GAIN)
Settings:
[999900]
5.0 - 50.0
5.0
Function:
It is possible to set a limit for the differentiator gain.
[0 - 1000]
[0]
[50 - 500]
[50]
12-5