11
ANTRIEBSTECHNIK
6
11
11
KEB COMBIVERT F4-C
Name: Basis
6
16.02.00
Functional Description
PI-Controller
©
KEB Antriebstechnik, 1999
All Rights reserved
Chapter
Section
Page
Date
PI-Controller
f_Preset
+
+
f_out
cn.27
cn.27
oP.33
oP.32
Picture 6.11.7
Controller action and limiting
6.11.7 Controller Action
and Limiting
The manipulated variable coming from the PI-Controller is limited with cn.27. In the
summation point the speed precontrol is added to the manipulated variable. The
parameters oP.32 and oP.33 limit the output frequency.
PI-Frequency limit (cn.27)
With cn.27 the maximum frequency change through the PI-Controller is determined.
The frequency can be specified in the range of 0…204,78 Hz with a resolution of
0,0125 Hz. The value applies to both directions of rotation.
Maximum output frequency
clockwise rotation (oP.32)
counter-clockwise rotation
oP.33)
These parameters limit the output frequency to the adjusted value. The limits are
necessary to permit the operation of the controller in the permissible operating range
of the application. All other limits (oP.4…oP.9) limit the setpoint value only, but not the
output frequency.
It is imperative to adjust these parameters for controlled operation to avoid
damages to the machine!
With cn.0 Bit 3 it is determined whether a change of rotational direction s possible,
when the sum of precontrol and manipulated variable is negative. This means that
this function must be deactivated for machines that are designed for one rotational
direction only.
To avoid fluctuations around 0Hz, the controller inverse amplification factor can be
disabled when the speed control is activated and no specified frequency is set. This
function is activated with cn.0 Bit 4 (see 6.11.2).
If the frequency limit or one of the max. output frequencies is reached, the I-component
of the controller can be frozen for as long as the limiting is active. This function is
activated with parameter cn.0 Bit 5 (see 6.11.2).
Freezing of I-component
(cn.0 Bit5)
Controller inverse amplification
factor at 0Hz
(cn.0 Bit4)
Change of rotational direction
(cn.0 Bit3)
The rate of change of the diameter signal can be limited through a ramp generator.
With cn.33 the time, that is required for a signal difference of 0…100%, can be adjusted
in the range of 0,0…300s,
Inc/dec-time for diameter
signal
(cn.33)
