Mitsubishi Electric FR-A720-0.4K Instruction Manual page 182

Setting of acceleration/deceleration time
and acceleration/deceleration pattern
Setting value "2"
[S-pattern acceleration
/deceleration B]
f1
f2
Time
Setting value "3"
[Anti-backlash measure
function]
Pr. 142
Pr. 140
Pr. 13
Pr. 143
Pr. 141
CAUTION
Setting the backlash measures increases the acceleration/deceleration time by the stopping time.
Frequency
Pr.382
Output frequency Output frequency Output frequency
Set frequency Set frequency Set frequency
Pr.380
S-pattern
acceleration/
OFF
deceleration
C switchover
(X20)
Parameter setting (%) Ts / T
S-pattern
acceleration
Ts
T
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. Make setting after confirming the function of each terminal.
172
(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.
Time
Set the acceleration/deceleration stopping frequency and time in Pr. 140 to Pr. 143.
Pr.381
Pr.383
Time
OFF
ON
×
100%
Linear
acceleration
Ts
(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.
Operation
X20 signal Acceleration
Pr. 380 Acceleration S-
OFF
pattern 1
Pr. 382 Acceleration S-
ON
pattern 2
⋅ Set % of time taken for forming an S-pattern in
as acceleration time is 100%.
383
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.
During During
Deceleration
Pr. 381 Deceleration
S-pattern 1
Pr. 383 Deceleration
S-pattern 2
Pr. 380 to Pr.