Mitsubishi Electric MR-J3-B-RJ006, Instruction Manual

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1. FUNCTIONS AND CONFIGURATION
1.2 Control block diagram
A fully closed loop control block diagram is shown below. The fully closed loop system is controlled in the load
side encoder unit.
Dual feedback
filter
(Note 2)
Parameter No.PE08
FBD
Servo motor
Linear encoder
Controller
(Motor side)
Feedback
pulses
accumulation
(Motor side)
Droop pulses
Load side
feedback
pulses
accumulation
(Note 1, 2)
Fully closed loop selection
Parameter No.PE01, PE08
FBN
S
Encoder pulse setting
(Refer to
section 5.1.6.)
Fully closed loop
control error detection
function selection
Parameter No.PE03
+
Control
Monitoring
Motor side feedback pulse
(Load side resolution unit)
Load side
droop pulses
Load side feedback pulse
+
+
+
+
+
+
Note. 1. Switching between semi closed loop control and fully closed loop control can be performed by changing the setting of
parameter No.PE01.
When semi closed loop control is selected, a control is always performed on the bases of the position data of the motor
encoder independently of whether the motor is at a stop or running.
2. When parameter No.PE01 "fully closed loop system" is valid, dual feedback control in which the motor feedback signal and
load side encoder feedback signal are combined by the dual feedback filter in parameter No.PE08 is performed.
In this case, fully closed loop control is performed when the motor is at a stop, and semi closed loop control is performed when
the motor is operating to improve control performance. When "4500" is set as the filter value of parameter No.PE08, fully
closed loop control is always performed.
The following table shows the functions of each control mode.
Control mode Description
Feature Position is controlled according to the motor side data.
Advantage
Since this control is insusceptible to machine influence (such as machine
resonance), the gains of the servo amplifier can be raised and the settling
time shortened.
Semi closed loop control
Disadvantage
If the motor side is at a stop, the side may be vibrating or the load side
accuracy not obtained.
Feature Position is controlled according to the motor side data and load side data.
Dual feedback control
Advantage
Control is performed according to the motor side data during operation,
and according to the load side data at a stop in sequence to raise the gains
during operation and shorten the settling time.
A stop is made with the load side accuracy.
Feature Position is controlled according to the load side data.
Advantage
The load side accuracy is obtained not only at a stop but also during
operation.
Fully closed loop control
Disadvantage
Since this control is susceptible to machine resonance or other influences,
the gains of the servo amplifier do not rise and the settling time increases.