Mitsubishi Electric FR-A820-00046 Instruction Manual page 422

(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/decel-
eration stopping frequency and time in Pr. 140 to 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 switcho-
ver (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
Tab. 5-96:
Fig. 5-93:
5 - 242
[Anti-backlash measure
function]
Pr. 140
Pr. 13
Pr. 143
Pr. 141
During acceleration
Pr. 380 "Acceleration S-pattern 1"
ON Pr. 382 "Acceleration S-pattern 2"
Selection of acceleration/deceleration curve S-pattern 1 or S-pattern 2
Frequency
Output frequency
Set frequency
S-pattern
acceleration/
deceleration C
switchover X20)
Characteristic for parameter 29 = 4
Fig. 5-92:
Anti-backlash measure function
Pr. 142
Time
Pr. 382
Pr. 380
OFF ON OFF
During deceleration
Pr. 381 "Deceleration S-pattern 1"
Pr. 383 "Deceleration S-pattern 2"
Pr. 381
Pr. 383
Time
Parameters
I002559E_B
I001551E