MITSUBISHI ELECTRIC Mitsubishi Programmable Logic Controller QD75D - Manual (Page 283)

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MELSEC-Q
8 OPR CONTROL
8.2.2 Machine OPR method
The method by which the machine OP is established (method for judging the OP position and
machine OPR completion) is designated in the machine OPR according to the configuration
and application of the positioning method.
The following table shows the six methods that can be used for this OPR method.
(The OPR method is one of the items set in the OPR parameters. It is set in " Pr.43 OPR
method" of the basic parameters for OPR.)
Pr.43
OPR method Operation details
Near-point dog method
Deceleration starts by the OFF ON of the near-point dog. (Speed is reduced to
" Pr.47 Creep speed".)
The operation stops at the first zero signal after the near-point dog turns from ON
OFF. When a "deviation counter clear output" is completed, the machine OPR is
completed.
Stopper method 1)
The stopper position is regarded as the OP.
After the deceleration starts by the OFF
ON of the near-point dog, the machine presses
against the stopper at the " Pr.47 Creep speed" and stops.
The machine OPR is regarded as completed on completion of the deviation counter clear
output provided after " Pr.49 OPR dwell time" passed after stoppage.
Stopper method 2)
The stopper position is regarded as the OP.
After the deceleration starts by the OFF
ON of the near-point dog, the machine presses
against the stopper at the " Pr.47 Creep speed" and stops.
The machine OPR is regarded as completed on completion of the deviation counter clear
output provided after the zero signal
is detected after stoppage.
Stopper method 3)
The stopper position is regarded as the OP.
The machine starts at the " Pr.47 Creep speed" from the beginning, then presses
against the stopper at the " Pr.47 Creep speed" and stops.
The machine OPR is regarded as completed on completion of the deviation counter clear
output provided after the zero signal
is detected after stoppage.
Count method 1)
The deceleration starts by the OFF ON of the near-point dog, and the machine moves
at the " Pr.47 Creep speed".
The machine stops at the zero signal after moving the distance set in the " Pr.50
Setting for the movement amount after near-point dog ON" from the near point dog OFF
ON position. When a "deviation counter clear signal output" is completed, the machine
OPR is regarded as completed.
Count method 2)
The deceleration starts by the OFF ON of the near-point dog, and the machine moves
at the " Pr.47 Creep speed".
The machine moves the distance set in the " Pr.50 Setting for the movement amount
after near-point dog ON" from the near point dog OFF ON position, and stops at that
position. The machine OPR is then regarded as completed.
: The following are the signals input as the zero signals of the QD75 in the corresponding OPR methods.
Near-point dog method, count method 1): Signal that is output as a single pulse at one motor revolution (e.g. Z-phase signal
output from the drive unit)
Stopper method 2), 3) : Signal that is output on detection of contact with the stopper. (Input externally)
REMARK
Creep speed
The stopping accuracy is poor when the machine suddenly stops from fast speeds. To
improve the machine's stopping accuracy, its must change over to a slow speed before
stopping. This speed is set in the " Pr.47 Creep speed".