Mitsubishi Electric 800 Series Instruction Manual page 277

(F) Setting of acceleration/deceleration time and acceleration/deceleration pattern
Backlash measures (Pr.29 = "3",Pr.140 to Pr.143)
• 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.
[Anti-backlash measure
function]
Pr. 140
Pr. 13
Pr. 141
Pr. 143
NOTE
• Setting the backlash measures increases the acceleration/deceleration time by the stopping time.
S-pattern acceleration/deceleration C (Pr.29 = "4", Pr.380 to Pr.383)
• Switch the acceleration/deceleration curve by the S-pattern acceleration/deceleration C switchover (X20) signal.
• To input the X20 signal, set "20" in any of Pr.178 to Pr.189 (Input terminal function selection) to assign the function to
the terminal.
X20 signal During acceleration
OFF Pr.380 Acceleration S-pattern 1
ON Pr.382 Acceleration S-pattern 2
Frequency
Output frequency Output frequency Output frequency
Set frequency Set frequency Set frequency
Pr.380
S-pattern
acceleration/
OFF
deceleration
C switchover
(X20)
• Set the ratio (%) of time for drawing an S-shape in Pr.380 to Pr.383 with the acceleration time as 100%.
Parameter setting (%) = Ts / T  100%
S-pattern
acceleration
Ts
276
PARAMETERS
Pr. 142
Time
Pr.381 Deceleration S-pattern 1
Pr.383 Deceleration S-pattern 2
Pr.381
Pr.382
Pr.383
OFF
ON
Linear
acceleration
Ts
T
During deceleration
Time