Mitsubishi Electric FR-F820-04750 Instruction Manual page 268

(F) Setting of acceleration/deceleration time and acceleration/deceleration pattern
S-pattern acceleration/deceleration B (Pr. 29 = "2")
This is useful for preventing collapsing stacks such as on a conveyor. S-pattern acceleration/deceler-
ation B can reduce the impact during acceleration/deceleration by accelerating/decelerating while
maintaining an S-pattern from the present frequency (f2) to the target frequency (f1).
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.
5 - 106
[S-pattern acceleration/
deceleration B]
f1
f2
Time
[Anti-backlash measure
function]
Pr. 140
Pr. 13
Pr. 143
Pr. 141
Fig. 5-22:
Characteristic for parameter 29 = 2
Fig. 5-23:
Anti-backlash measure function
Pr. 142
Time
Parameters
I002558E_B
I002559E_B