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MELSEC-Q
9 MAJOR POSITIONING CONTROL
9.2.7 2-axis fixed-feed control (interpolation)
In "2-axis fixed-feed control" ("
Da.2
Control system" = fixed-feed 2), two motors are
used to carry out fixed-feed control in a linear path while carrying out interpolation for
the axis directions set in each axis.
In fixed-feed control, any remainder of the movement amount designated in the
positioning data is rounded down if less than that required for control accuracy to
output the same amount of pulses. (The remainder of the movement amount with an
accuracy below the control accuracy does not affect the regular controls.)
(Refer to Section 9.1.6 "Interpolation control" for details on interpolation control.)
Operation chart
In incremental system 2-axis fixed-feed control, the addresses (
Md.20
Current
feed value) of the current stop position (start addresses) of both axes are set to
"0". Linear interpolation positioning is then carried out from that position to a
position at the end of the movement amount set in "
Da.6
Positioning
address/movement amount". The movement direction is determined by the sign of
the movement amount.
" Md. 20 Current feed value" of each axis
is set to "0" at the positioning start
(0,0)
(0,0)
(0,0)
X axis
Y axis
Designated movement
amount
Designated movement
amount
Restrictions
(1) An axis error "Continuous path control not possible (error code: 516)" will
occur and the operation cannot start if "continuous path control" is set in
"
Da.1
Operation pattern". ("Continuous path control" cannot be set in fixed-
feed control.)
(2) If the movement amount of each axis exceeds "1073741824 (=2
30
)" when "0:
Composite speed" is set in "
Pr.20
Interpolation speed designation method",
the "Outside linear movement amount range error (error code: 504)" occurs at
a positioning start and positioning cannot be started. (The maximum
movement amount that can be set in "
Da.6
Positioning address/movement
amount" is "1073741824 (= 2
30
)".
(3) "Fixed-feed" cannot be set in "
Da.2
Control system" in the positioning data
when "continuous path control" has been set in "
Da.1
Operation pattern" of
the immediately prior positioning data. (For example, if the operation pattern of
positioning data No. 1 is "continuous path control", fixed-feed control cannot
be set in positioning data No. 2.) An axis error "Continuous path control not
possible (error code: 516)" will occur and the machine will carry out a
deceleration stop if this type of setting is carried out.