9 - 23
MELSEC-Q
9 MAJOR POSITIONING CONTROL
Starting the interpolation control
The positioning data Nos. of the reference axis (axis in which interpol ation control
was set in " Da.2 Control system") are started when starting the interpolation
control. (Starting of the interpolation axis is not required.)
The following errors or warnings will occur and the positioning will not start if both
reference axis and the interpolation axis are started.
• Reference axis : Interpolation wh ile interpolation axis BUSY (error code:
519)
• Interpolation axis : Control system setting error (error code: 524), start during
operation (warning code: 100).
Interpolation control continuous positioning
When carrying out interpolation control in which "continuous p ositioning control"
and "continuous path control" are designated in the operation pattern, t he
positioning method for all positioning data from the started positio ning data to the
positioning data in which "positioning complete" is set mus t be set to interpolation
control.
The QD75 may malfunction if a control system other than interpola tion control is
set.
Speed during interpolation control
Either the "composite speed" or "reference axis speed" can be d esignated as the
speed during interpolation control.
(Pr.20 Interpolation speed designation method)
Only the "Reference axis speed" can be designated in the followin g interpolation
control.
When a "composite speed" is set and positioning is started, the "Inter polation
mode error (error code: 523)" occurs, and the system will not start.
• 4-axis linear interpolation
• 2-axis speed control
• 3-axis speed control
• 4-axis speed control
Cautions in interpolation control
(1) If a stepping motor is used, the circular interpolation control can not be carried
out.
Ensure to use a servomotor when the circular interpolation control is car ried
out.
(2) If either of the axes exceeds the " Pr.8 Speed limit value" in the 2 to 4 axes
speed control, the axis which exceeded the speed limit value is c ontrolled by
the speed limit value.
For the other axes which perform interpolation, the speed can be suppres sed
by the ratio of a command speed.
If the reference axis exceeds " Pr.8 Speed limit value" during 2- to 4-axis
linear interpolation control, 2- to 4-axis fixed-feed control or 2-ax is circular
interpolation control, the reference axis is controlled at the speed limit value.
(The speed limit does not function on the interpolation axis side.)
(3) In 2-axis interpolation, you cannot change the combination of int erpolated axes
midway through operation.