Mitsubishi Electric FR-A800 Series Instruction Manual page 375

NOTE
• When the RT or X9 signal turns ON during acceleration or deceleration with the S-pattern acceleration/deceleration B enabled,
a pattern of acceleration or deceleration changes to linear at the moment.
 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. 13
Pr. 141
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
OFF Pr.380 Acceleration S-pattern 1
ON Pr.382 Acceleration S-pattern 2
Frequency
Set frequency Set frequency Set frequency
S-pattern
acceleration/
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
T
374
5. PARAMETERS
5.8 (F) Setting of acceleration/deceleration time and acceleration/deceleration pattern
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Pr. 142
Pr. 140
Time
Pr. 143
During acceleration
Pr.382
Output frequency Output frequency Output frequency
Pr.380
OFF OFF
ON
Linear
acceleration
Ts
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During deceleration
Pr.381 Deceleration S-pattern 1
Pr.383 Deceleration S-pattern 2
Pr.381
Pr.383
Time