MITSUBISHI ELECTRIC Mitsubishi Programmable Logic Controller QD75D - Manual (Page 343)

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MELSEC-Q
9 MAJOR POSITIONING CONTROL
9.2.6 1-axis fixed-feed control
In "1-axis fixed-feed control" (" Da.2 Control system" = fixed-feed 1), one motor is
used to carry out fixed-feed control in a set axis direction.
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.)
Operation chart
In 1-axis fixed-feed control, the address ( Md.20 Current feed value) of the current
stop position (start point address) is set to "0". Positioning is then carried out 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 movement amount sign.
0 0 0 0 0
" Md. 20 Current feed
value" is set to "0" at
the positioning start
Designated movement
Positioning
start
amount
Reverse direction Forward direction
Stop position
Movement direction for
a negative movement amount
Movement direction for
a positive 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) "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.