Effects On Path Acceleration; Substitute Characteristic Curve - Siemens SINUMERIK 840D sl Function Manual

B2: Acceleration
5.2 Functions
The key data for the characteristic curves equate to:
v
max
v
red
a
max
a
red
5.2.19.2

Effects on path acceleration

Function
The path acceleration characteristic curve is generated on the basis of the types of
characteristic for the axes that are of relevance for the path. If axes with different types of
characteristic curve are interpolated together, the acceleration profile for the path acceleration
will be determined on the basis of the reduction type that is most restrictive.
The following order of priorities applies, whereby 1 = top priority:
1. Acceleration reduction: 0 = constant characteristic
2. Acceleration reduction: 1 = hyperbolic characteristic
3. Acceleration reduction: 2 = linear characteristic
4. No acceleration reduction effective
A situation, whereby no acceleration reduction is active, arises for example when:
MD35220 $MA_ACCEL_REDUCTION_SPEED_POINT = 1
and/or
MD35230 $MA_ACCEL_REDUCTION_FACTOR = 0
Note
Machine axes featuring stepper motor and DC drive can be interpolated together.
5.2.19.3

Substitute characteristic curve

Function
If the programmed path cannot be traversed with the acceleration curve parameterized in the
machine data of the participating axes, e.g. if kinematic transformation and acceleration types
BRISK or SOFT are active, a substitute curve is generated by reducing the dynamic limit values.
The reduced dynamic limit values are calculated to ensure that the substitute characteristic
curve provides the best possible compromise between maximum velocity and constant
acceleration.
276
= $MA_MAX_AX_VELO
= $MA_ACCEL_REDUCTION_SPEED_POINT * $MA_MAX_AX_VELO
= $MA_MAX_AX_ACCEL
= (1 - $MA_ACCEL_REDUCTION_FACTOR) * $MA_MAX_AX_ACCEL
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions