Siemens SIMATIC S5 Manual page 34

The maximum acceleration time is 7.8 seconds. The minimum acceleration time is 15 ms. This
means that ~ must be between 5 ms and 2.6 seconds, The maximum and minimum frequency
increase is obtained as follows:
2.6s
5ms
With all traversing movements carried out at maximum speed (frequency), the full acceleration
and deceleration ramp is used for acceleration and deceleration. With traversing movements at
lower speeds, the acceleration is continued only until the required speed (frequency fv) is
achieved.
fmax –
fss
Fig. 2/1 2 Acceleration to frequencies less than frnm
The advantage of this acceleration and deceleration ramp is that a greater distance is travelled
than with linear acceleration within the same time.
To avoid the drive being damaged when the traversing movement is aborted,
e.g. by a software or hardware limit switch, there must be sufficient braking dis-
tance after the limit switches.
The braking distance for any speed (frequency f.) can be calculated as followed:
Ramp up time tv to traversing frequency fv
The acceleration and braking distance can then be calculated as follows:
Distance = positioning resolution x (F x (tv + ~ x (e (- "T) - 1)) + f% x tv
- – - – - – - –
I
Machine Data and their Structure
(fmax-fss)/0.95+fss
– –
t
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