Mitsubishi Electric Melservo MR-J3-100B, Handbook

Page: 64 / 590

Part 2: Review on Replacement of MR-J3-_A_ with MR-J4-_A_
2 - 31
MR-J3-_A_ MR-J4-_A_
Control
mode
No. Name and function
Initial
value
No.
Name and function
Initial
value
PB03 Position command acceleration/deceleration time
constant (position smoothing)
Used to set the time constant of a low-pass filter in
response to the position command.
You can use [Pr. PB25] to choose the primary delay
or linear acceleration/deceleration control system.
When you choose linear acceleration/deceleration,
the setting range is 0 to 10ms. Setting of longer than
10ms is recognized as 10ms.
POINT
 When you have chosen linear
acceleration/deceleration, do not select
control selection ([Pr. PA01])
and restart after instantaneous power
failure ([Pr. PC22]). Doing so
will cause the servo motor to make a
sudden stop at the time of position
control switching or restart.
(Example) When a command is given from a
synchronizing detector, synchronous
operation can be started smoothly if
started during line operation.
Synchronizing
detector
Start
Servo amplifier
Servo motor
Without time
constant setting
Servo motor
speed
Start
With time
constant setting
ON
OFF
t
0 PB03
Same as MR-J3
0 P
Position command acceleration/
deceleration time constant (position smoothing)
Set the constant of a primary delay to the position
command.
You can select a control method from "Primary
delay" or "Linear acceleration/deceleration" in [Pr.
PB25 Function selection B-1]. When the linear
acceleration/deceleration is selected, the setting
range is 0 ms to 10 ms. Setting of longer than 10 ms
will be recognized as 10 ms.
When the linear acceleration/deceleration is
selected, do not set the "Control mode selection"
([Pr. PA01]) to the setting other than "_ _ _ 0".
Doing so will cause the servo motor to make a
sudden stop at the time of position control mode
switching.
(Example) When a command is given from a
synchronizing encoder, synchronous
operation will start smoothly even if it
starts during line operation.
Synchronizing
encoder
Start
Servo motor
Servo amplifier
ON
OFF
With time
constant setting
Without time
constant setting
Servo motor
speed
Start
t
Setting range: 0 to 65535
PB04 Feed forward gain
Set the feed forward gain. When the setting is
100%, the droop pulses during operation at constant
speed are nearly zero. However, sudden
acceleration/deceleration will increase the
overshoot. As a guideline, when the feed forward
gain setting is 100%, set 1s or longer as the
acceleration time constant up to the rated speed.
0 PB04 Same setting as MR-J3 0 P
Feed forward gain
Set the feed forward gain.
When the setting is 100%, the droop pulses during
operation at constant speed are nearly zero. When
the super trace control is enabled, constant speed
and uniform acceleration/deceleration droop pulses
will be almost 0. However, sudden
acceleration/deceleration will increase the
overshoot. As a guideline, when the feed forward
gain setting is 100%, set 1 s or more as the
acceleration time constant up to the rated speed.
Setting range: 0 to 100