Lenze 8600 series - Frequency Pilot Control

Code Name
Parameter (Factory setting is printed in bold) Acceptance
CO26 Constant for CO25 = -1 -, -2-, -4-
ON-LINE
CO25 (preselection of the analog inputs):
xxxx mV factory setting
-1000 mV
11 mv)
+lOOO mV
CO25 = -1 o-, -ll-
(preselection of the digital-frequency
inputskcremental encoder inputs):
-l-
512 pulse/Hz or incrementskevolution
-2. 1024 pulse/Hz or increments/revolution
-3- 2048 pulse/Hz or incrementslrevolution
-4- 4096 pulse/Hz or incrementskevolution
Adjustment for CO25 = -l-, -2., -4-
CO25 (preselection of the analog inputs):
1 .ooo -2.500 (0.001)
CO25 =-lO-, -11.
(preselection of the digital-frequency
inputskrcremental encoder inputs):
1 .ooo -5.000
(0.001)
+5.000
4.3 Frequency Pilot control
For applications where the act. value Signal is directly proportional
to the Speed of the drive (actual Speed) it is advantageous to pilot-
control the output frequency with the setpoint or act. value. The
influence of the PI controller tan be limited such that only the
maximum machine Slip to be expected is controlled.
Setpoint Pilot control
A Pilot control of the output frequency with the setpoint offers the
advantage that the drive cannot accelerate unexpectedly if the act.
value Signal fails (tacho failure). The ramp generator for the
setpoint must be set correspondingly so that the drive is able to
follow setpoint changes. (Tir-, Tit setting as for frequency control).
Actual value Pilot control
When the output frequency is pilot-controlled using the act. value,
the machine is supplied with the synchronous frequency which
corresponds to the actual Speed, without the influence of the Pl
controller (output Signal = 0). The Pl controller is only activated
effective if setpoint 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 direction.
The advantage of act. value pilot control is that the setpoint slew
rate does not have to be limited (Tir, Tir = 0) and that the drive tan
run through a large Speed 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 case of inadequate gain of the actual value.
If you want to use the act. value Pilot control, first adjust the act.
value gain with setpoint pilot control. After successful adjustment
you tan then Change to act. value Pilot control.
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