Siemens SINUMERIK 840Di Function Manual page 251

Substitute characteristic curve with curved path sections
In the case of curved path sections, normal and tangential acceleration are considered
together. The path velocity is reduced so that only up to 25% of the speed-dependent
acceleration capacity of the axes is required for normal acceleration. The remaining 75% of
the acceleration capacity is set aside for the tangential acceleration, i.e., deceleration/
acceleration on the path.
Fig. 2-10
a :
N
a
ers
v
ers
r:
Block transitions with continuous-path mode
If continuous-path mode is active, non-tangential block transitions result in axial velocity
jumps when the programmed path velocity is used for traversing.
As a result, the path velocity is controlled in such a way that prevents any axial velocity
proportion from exceeding the creep velocity v
Deceleration ramp with continuous-path mode and LookAhead
In the case of consecutive part program blocks with short paths, an acceleration or
deceleration operation may be spread over several part program blocks.
In such a situation LookAhead also takes into account the parameterized speed-dependent
acceleration characteristic.
Acceleration (B2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Substitute path characteristic curve: Curved path
Normal acceleration
: Substitute characteristic curve constant acceleration
: Substitute characteristic curve velocity
Path radius
2.18 Knee-shaped acceleration characteristic curve
at the time of the block transition.
red
Detailed Description
2-39