Mitsubishi Electric FR-F740 EC Instruction Manual page 232

Acceleration and deceleration
S-pattern acceleration/deceleration A (Pr. 29 = 1)
For machine tool spindle applications, etc.
Used when acceleration/deceleration must be made in a short time to a high-speed range of not
lower than base frequency. In this acceleration/deceleration pattern, Pr. 3 "Base frequency" (fb)
is the inflection point of the S-pattern (refer to Fig. 6-35) and you can set the acceleration/de-
celeration time appropriate for motor torque reduction in a constant-output operation region of
base frequency or higher.
Hz
fm
S-pattern acceleration/deceleration B (Pr. 29 = 2)
When a setting of "2" is entered frequency changes are executed with an S-pattern. For exam-
ple, if a drive is accelerated from 0 to 30Hz and then re-accelerated to 50Hz then each accel-
eration sequence (i.e. the first sequence from 0 to 30Hz and the second from 30Hz to 50Hz) will
be executed with an S-pattern. The time for the S-pattern is not longer than that for linear ac-
celeration (refer to Fig. 6-36). This prevents jolts in drive operation, for example for conveyor belt
and positioning drive systems.
f1
f2
NOTE As the acceleration/deceleration time of S-pattern acceleration/deceleration A, set the time
taken until Pr. 3 "Base frequency" is reached, not Pr. 20 "Acceleration/deceleration refer-
ence frequency".
6 - 82
S-pattern acceleration/
deceleration A
Time
S-pattern acceleration/
deceleration C
Time
Fig. 6-35:
Characteristic for parameter 29 = "1"
t
Fig. 6-36:
Characteristic for parameter 29 = "2"
t
Parameter
I000016C
I000017C