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MELSEC-Q
9 MAJOR POSITIONING CONTROL
(3) Speed handling
(a) Continuous path control command speeds are se t with each
positioning data.
The QD75 then carries out the positioning at t he speed designated
with each positioning data.
(b) The command speed can be set to "–1" in contin uous 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". *1
(The "current speed" will be displayed in the c ommand speed when
the positioning data is set with a periphera l device. The current speed
is the speed of the positioning control bein g 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 th e
command speed.
2) If the speed is changed in the previous positioning data when "–1"
is set in the command speed, the operation c an be continued at
the new speed.
3) An error "no command speed" (error code: 503) occurs and
positioning cannot be started if "–1" is se t in the command speed
of the first positioning data at start.
[Relation between the command speed and current s peed]
The current speed is
changed even if the command
speed is not reached in P2.
2000
1000
3000
30001000
1000
-1
3000
-1
3000
-1
3000
P1 P2 P3 P4 P5Speed
3000
Da. 7 Command speed
Md. 36 Current speed
2000
1000
3000
P1 P2 P3 P4 P5Speed
3000
1000
1000
-1
3000
-1
3000
-1
30003000
Da. 7 Command speed
Md. 36 Current speed
*2
*1
POINTS
(1) In the continuous path control, a speed var iation will not occur using the near-pass func tion when the
positioning data is switched (Refer to Sect ion 12.3.3 "Near-pass function").
(2) The QD75 holds the command speed set wit h the positioning data, and the latest valu e of the speed
set with the speed change request as the " Md.27 Current speed". It controls the operation at t he
"current speed" when "-1" is set in the com mand speed.
(Depending on the relation between the movement am ount and the speed, the feedrate may not reac h
the command speed value, but even then the curren t speed will be updated. *2)
(3) When the address for speed change is iden tified beforehand, generate and execute the positioning
data for speed change by the continuous path control to carry ou t t he spee d ch an ge wi thou t r eq ues ti ng
the speed change with a sequence program.