KFU 2-/4-
142
The parameter
Maximum leading
426
limits the difference between the output of
the ramp and the current actual value of the drive. The set maximum deviation is a
dead time for the control system which should be kept as low as possible.
In case the drive is loaded heavily and high acceleration and deceleration values are
selected it is possible, that a set controller limit is reached while the drive is acceler-
ated or decelerated. In this case, the drive cannot follow the defined acceleration or
deceleration ramps. With
Maximum leading
426
, you can limit the max. leading of
the ramp.
Parameter
Settings
No. Description
Min.
Max.
Fact.
sett.
426 Maximum leading
0.01 Hz
999.99 Hz
5.00 Hz
Example:
Fixed value at ramp output = 20 Hz, current actual value of drive =
15 Hz, selected
Maximum leading
426
= 5 Hz
The frequency at the ramp output is increased to 15 Hz only, it is not increased fur-
ther. The difference (leading) between the frequency value at the ramp output and
the current actual frequency of the drive is limited to 5 Hz in this way.
The load occurring in a linear acceleration of the drive is reduced by the adjustable
modification speeds (S curve). The non-linear course of the frequency is defined as a
ramp and states the time range in which the frequency is to be guided to the set
ramp. The values set with parameters 420 to 423 are maintained regardless of the
selected ramp times.
