Acceleration/Deceleration Pattern (Pr.29, Pr.140 To Pr.143) - Mitsubishi Electric F700 Instruction Manual

Setting of acceleration/deceleration time
and acceleration/deceleration pattern
4.7.3

Acceleration/deceleration pattern (Pr.29, Pr.140 to Pr.143)

You can set the acceleration/deceleration pattern suitable for application.
You can also set the backlash measures that stop acceleration/deceleration once at the parameter-set
frequency and time during acceleration/deceleration.
Parameter
Number
Acceleration/deceleration pattern
29
selection
140 Backlash acceleration stopping frequency
141 Backlash acceleration stopping time
142 Backlash deceleration stopping frequency
143 Backlash deceleration stopping time
The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 156)
Setting value "0"
[Linear acceleration
/ deceleration]
Time
Setting value "1"
[S-pattern acceleration
/deceleration A]
fb
Time
CAUTION
⋅ As the acceleration/deceleration time of S-pattern acceleration/deceleration A, set the time taken until Pr. 3 Base frequency is
reached, not Pr. 20 Acceleration/deceleration reference frequency.
Setting value "2"
[S-pattern acceleration
/deceleration B]
f1
f2
Time
Setting value "3"
[Anti-backlash measure
function]
Pr. 140
Pr. 13
Pr. 143
Pr. 141
CAUTION
Setting the backlash measures increases the acceleration/deceleration time by the stopping time.
♦ Parameters referred to ♦
Pr. 3 Base frequency Refer to page 80
Pr. 7 Acceleration time, Pr. 8 Deceleration time, Pr. 20 Acceleration/deceleration reference frequency
94
Name
(1) Linear acceleration/ deceleration (Pr. 29 = "0", initial value)
⋅ When the frequency is changed for acceleration, deceleration, etc. in inverter
operation, the output frequency is changed linearly (linear acceleration/
deceleration) to reach the set frequency without straining the motor and
inverter. Linear acceleration/deceleration has a uniform frequency/time
slope.
(2) S-pattern acceleration/deceleration A (Pr. 29 = "1")
⋅ For machine tool spindle applications, etc.
Used when acceleration/deceleration must be made in a short time to a high-
speed range of not lower than the base frequency. In this acceleration/
deceleration pattern, Pr. 3 Base frequency (fb) is the inflection point of the S
pattern and you can set the acceleration/deceleration time appropriate for
motor torque reduction in a constant-power operation region of base
frequency or higher.
(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.
Pr. 142
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.
Initial Setting
Value Range
0 Linear acceleration/ deceleration
1 S-pattern acceleration/deceleration A
0
2 S-pattern acceleration/deceleration B
3 Backlash measures
1Hz 0 to 400Hz
Set the stopping frequency and time
0.5s 0 to 360s
for backlash measures.
1Hz 0 to 400Hz
Valid when Pr. 29 = 3
0.5s 0 to 360s
Description
Refer to page 91