Mitsubishi Electric MELSEC-L LD75D, User Manual

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349
CHAPTER 9 MAJOR POSITIONING CONTROL
9
9.
1 O
u
tline
o
f Major Pos
itioning
Cont
rols
(c) Speed handling
• Continuous path control command speeds are set with each positioning data. The LD75 then carries out the
positioning at the speed designated with each positioning data.
• 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 GX Works2. The current speed is
the speed of the positioning control being executed currently.)
[Relation between the command speed and current speed]
● In the continuous path control, a speed variation will not occur using the near-pass function when the positioning data is
switched. (
 Page 525, Section 12.3.3)
●
The LD75 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.)
● 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
program.

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.

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.

An error "no command speed" (error code: 503) occurs and positioning cannot be started if "-1" is
set in the command speed of the first positioning data at start.
2000
1000
3000
3000
Command speed
Current speed
1000
1000 -1
3000
-1
3000
-1
3000
P1 P2 P3 P4 P5 Speed
3000
Da. 8
Md.27
2000
1000
3000
3000
Command speed
Current speed
1000
1000 -1
3000
-1
3000
-1
3000
P1 P2 P3 P4 P5 Speed
3000
Da. 8
Md.27
The current speed is
changed even if the command
speed is not reached in P2.