Mitsubishi MELSEC-Q QD77MS, User Manual

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Chapter 9 Major Positioning Control
(3) Speed handling
(a) Continuous path control command speeds are set with each
positioning data.
The QD77MS then carries out the positioning at the speed designated
with each positioning data.
(b) The command speed can be set to "–1" in continuous path control.
The control will be carried out at the speed used in the previous
positioning data No. if the command speed is set to "–1".
(The "current speed" will be displayed in the command speed when
the positioning data is set with a GX Works2. The current speed is the
speed of the positioning control being executed currently.)
1) The speed does not need to be set in each positioning data when
carrying out uniform speed control if "–1" is set beforehand in the
command speed.
2) If the speed is changed or the override function is executed, in the
previous positioning data when "–1" is set in the command speed,
the operation can be continued at the new speed.
3) An error "no command speed error (error code: 503)" occurs and
positioning cannot be started if "–1" is set in the command speed
of the first positioning data at start.
[Relation between the command speed and current speed]
3000
3000
-1
3000
-1
3000
-1
3000
1000
1000
P2 P3 P4 P5 P1
2000
1000
3000
Command speed
Da. 8
Current speed Md. 27
Speed
3000
3000
-1
3000
-1
3000
-1
3000
1000
1000
P2 P3 P4 P5 P1
2000
1000
3000
Command speed
Da. 8
Current speed Md. 27
Speed
The current speed is changed
even if the command speed is not
reached in P2.
POINTS
(1) In the continuous path control, a speed variation will not occur using the near-pass function when the
positioning data is switched (Refer to Section 13.3.3 "Near pass function").
(2) The QD77MS holds the command speed set with the positioning data, and the latest value of the speed
set with the speed change request as the "
Md.27
Current speed". It controls the operation at the
"current speed" when "-1" is set in the command speed.
(Depending on the relation between the movement amount and the speed, the feedrate may not reach
the command speed value, but even then the current speed will be updated.)
(3) When the address for speed change is identified beforehand, generate and execute the positioning
data for speed change by the continuous path control to carry out the speed change without requesting
the speed change with a sequence program.