3 frequency control – Lenze 8615E User Manual
Page 78

Code
Name
Parameter
setting is printed in bold)
Acceptance
CO26 Constant for
-1 -2-,
ON-LINE
C O 2 5
( p r e s e l e c t i o n o f t h e a n a l o g i n p u t s ) :
xxxx
factory setting
-1000
= -1 o-,
( p r e s e l e c t i o n o f t h e d i g i t a l - f r e q u e n c y
encoder inputs):
512
or
1024
or increments/revolution
-3-
2048
or
-4-
4096
or
Adjustment for CO25
C O 2 5
( p r e s e l e c t i o n o f t h e a n a l o g i n p u t s ) :
1 .ooo
- 2 . 5 0 0
( 0 . 0 0 1 )
( p r e s e l e c t i o n o f t h e d i g i t a l - f r e q u e n c y
encoder inputs):
1 .ooo
- 5 . 0 0 0
( 0 . 0 0 1 )
4.3
Frequency
control
For applications where the act. value
is directly proportional
to the
of the drive (actual
it is advantageous to pilot-
control the output frequency with the
or act. value. The
influence of the PI controller
be limited such that only the
maximum machine
to be expected is
control
A
control of the output frequency with the
offers the
advantage that the drive
accelerate unexpectedly if the act.
value
fails
failure). The ramp generator for the
must be set correspondingly so that the drive is able to
follow
setting as for frequency control).
value
control
When the output frequency is pilot-controlled using the act. value,
the machine is supplied with the
frequency
corresponds to the actual
without the influence of the Pl
controller (output
0). The Pl controller is only activated
if
and act. value are not identical. When the Pl
controller increases or decreases the output frequency, a torque is
generated in the machine so that the drive accelerates in the
desired
The advantage of act. value pilot control is that the
slew
rate does not have to be limited
= 0) and that the drive
run through a large
setting range with the set torque
according to the set influence of the Pl controller.
A disadvantage is that the drive may accelerate unexpectedly in
the
of inadequate gain of the actual value.
If you want to use the act. value
control, first
the act.
value gain with
pilot control. After successful adjustment
you
then
to act. value
control.
76