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5.3.2 Relative positioning
In the case of relative positioning, the target position is added to the current position. Since no fixed
zero is required, referencing is not compulsory. It does, however, make sense in many cases, in order
to bring the drive to a defined position.
Adding of relative positionings allows for example endless positioning in one direction for a trimming
unit or a conveyor belt (incremental dimension).
5.3.3 Absolute positioning
In the case of absolute positioning the target position is a fixed (absolute) position referred to the zero
or reference point. The target position is approached independently of the current position. In order to
execute an absolute positioning we recommend prior referencing of the drive.
5.3.4 Driving profile generator
Driving profiles are categorized in time-optimal and jerk-limited positioning. In the case of time-optimal
positioning the maximum set acceleration is used for starting and braking. The drive approaches the
target in the shortest time possible, the velocity profile is trapezoidal, and the acceleration profile is
block-shaped.
In the case of jerk-limited positioning the acceleration profile is trapezoidal and the velocity profile is
therefore a curve of third order. Since the acceleration changes continuously, the drive is extremely
gentle on the mechanics.
a(t)
a(t)
a(t)
t
t
t
v(t)
t
v(t)
t
v(t)
t
at time optimal
jerk limit
jerk limit
Figure 4:
Driving profiles of the servo drive ARS 2100 SE
Product Manual „Servo drives ARS 2100 SE“
Version 5.0
