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177
Setting of acceleration/deceleration time
and acceleration/deceleration pattern
4
PARAMETERS
(3) S-pattern acceleration/deceleration B (
Pr. 29
=
"2")
⋅ For prevention of load shifting in conveyor and other applications
Since acceleration/deceleration is always made in an S shape from current
frequency (f2) to target frequency (f1), this function eases shock produced at
acceleration/deceleration and is effective for load collapse prevention, etc.
(4) Backlash measures (
Pr. 29
=
"3", Pr. 140 to Pr. 143)
⋅ What is backlash?
Reduction gears have an engagement gap and have a dead zone between
forward rotation and reverse rotation. This dead zone is called backlash, and
this gap disables a mechanical system from following motor rotation.
More specifically, a motor shaft develops excessive torque when the direction of
rotation changes or when constant-speed operation shifts to deceleration,
resulting in a sudden motor current increase or regenerative status.
⋅ To avoid backlash, acceleration/deceleration is temporarily stopped.
Set the acceleration/deceleration stopping frequency and time in Pr. 140 to Pr.
143.
CAUTION
Setting the backlash measures increases the acceleration/deceleration time by the stopping time.
(5) S-pattern acceleration/deceleration C (Pr. 29 =
"4", Pr. 380 to Pr. 383)
⋅ With the S-pattern acceleration/deceleration C switch
signal (X20), an acceleration/deceleration curve S-pattern 1
or S-pattern 2 can be selected.
⋅ For the terminal used for X20 signal input, set "20" in any of
Pr. 178 to Pr. 189 (input terminal function selection) to assign
the function.
Parameter setting (%) Ts / T
× 100%
⋅ Set % of time taken for forming an S-pattern in
Pr. 380 to Pr.
383
as acceleration time is 100%.
CAUTION
⋅ Change the S pattern acceleration/deceleration C switch (X20 signal) after the speed becomes constant.
⋅ S pattern operation before switching continues even if the X20 signal is changed during acceleration or deceleration.
⋅ The X20 signal can be assigned to the input terminal using any of Pr. 178 to Pr. 189 (input terminal function selection). Changing
the terminal assignment may affect the other functions. Set parameters after confirming the function of each terminal.
f1
Setting value "2"
[S-pattern acceleration
/deceleration B]
f2
Time
Set frequency
(Hz)
Output frequency
(Hz)
Pr. 142
Pr. 143
Pr. 141
Pr. 140
P
r. 13
Output frequency (Hz)
[Anti-backlash measure
function]
Setting value "3"
Time
Pr.382
Pr.383
Pr.381
S-pattern
acceleration/
deceleration
C switchover
(X20)
OFF
OFF
ON
Output frequency
Output frequency
Output frequency
Set frequency
Set frequency
Set frequency
Pr.380
Frequency
Tim
e
Operation
X20 signal
During
Acceleration
During
Deceleration
OFF
Pr. 380 Acceleration S-
pattern 1
Pr. 381 Deceleration
S-pattern 1
ON
Pr. 382 Acceleration S-
pattern 2
Pr. 383 Deceleration
S-pattern 2
S-pattern
acceleration
Linear
acceleration
Ts
T
Ts
REMARKS
⋅ At a start, the motor starts at Pr. 13 Starting frequency when the
start signal turns ON.
⋅ If there is a difference between the speed command and speed
at a start of deceleration due to torque limit operation etc., the
speed command is matched with the speed to make
deceleration.