Mitsubishi Electric FR-A700 Series, Техническое руководство

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PARAMETER
2.11 Position control by vector control
2.11.1 Position control
(A700)
(1) Control block diagram
The following shows a basic control block diagram during position control.
(2) Operation
The speed command given to rotate the motor is
calculated to zero the difference between the number
of internal command pulse train pulses (when [
Pr. 419
= 0], the number of pulses set by parameter ( [
Pr. 465
to 494
]) is changed to the command pulses in the
inverter) and the number of pulses fed back from the
motor end encoder.
1) When a pulse train is input, pulses are
accumulated in the deviation counter and these
droop pulses act as position control pulses to give
the speed command.
2) As soon as the motor starts running under the
speed command of the inverter, the encoder
generates feed back pulses and the droop of the
deviation counter is counted down. The deviation
counter maintains a given droop pulse value to
keep the motor running.
3) When the command pulse input stops, the droop
pulses of the deviation counter decreases,
reducing the speed. The motor stops when there
are no droop pulses.
4) When the number of droop pulses has fallen
below the value set in [
Pr. 426 In-position width
], it
is regarded as completion of positioning and the
in-position signal (Y36) turns ON.
For conditional position control function by contact
input, the terminals STF and STR provide the forward
(reverse) command signal. The motor can run only in
the direction where the forward (reverse) signal is
ON. Turning the STF signal OFF does not run the
motor forward and turning the STR signal OFF does
not run the motor reverse.
The pulse train is rough during acceleration and fine
at the maximum speed. During deceleration the pulse
train is rough and at last there are no pulses. The
motor stops shortly after the command pulses stop.
This time lag is necessary for maintaining the stop
accuracy and called stop settling time.
A700
RH
RM
RL
REX
STF
STR
JOG
NP
[ Pr. 4 to 6 ]
[ Pr. 24 to 27 ]
[ Pr. 232 to 239 ]
[ Pr. 7, 44, 110 ]
[ Pr. 465 to 494 ]
travel
Multi-speed,
communication
[ Pr. 419 = 0 ]
Position command
source selection
[ Pr. 420 ]
[ Pr. 421 ]
Position command
acceleration/deceleration
time constant
[ Pr. 424 ]
Position feed
forward
command filter
[ Pr. 425 ]
Command pulse selection
Electronic
gear
Command pulse
+
- Deviation
counter
+
+
Encoder
IM
Speed control
-
Clear signal
selection
[ Pr. 429 ]
Differentiation
[ Pr. 8 , 45, 111 ]
Pulse train sign
[ Pr. 419 = 2 ]
PGP, PP
PGN, NP
[ Pr. 419 = 1 ]
Command pulse
selection
[ Pr. 428 ]
Command pulse
selection
[ Pr. 428 ]
Command pulse
(FR-A7AL)
Command pulse
(FR-A7AL)
Position feed
forward gain
[ Pr. 423 ]
Position
loop gain
[ Pr. 422 ]
Acceleration
Time
Deceleration
Stop
settling time
Motor speed
Pulse distribution
Droop pulse value
Pulse train Rough Fine Rough
LX signal
Servo ON
STF (STR)
Forward (reverse)
Y36 signal
In-position signal
Command pulse frequency
[PPS]
Motor speed [r/min]