MITSUBISHI ELECTRIC Mitsubishi Programmable Logic Controller QD75D - Manual (Page 297)

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MELSEC-Q
8 OPR CONTROL
Restrictions
When this method is used, a deviation will occur in the stop position (OP)
compared to other OPR methods because an error of about 1 ms occurs in taking
in the near-point dog ON.
Precautions during operation
(1) An error "Count method movement amount fault (error code: 206)" will occur
and the operation will not start if the " Pr.50 Setting for the movement
amount after near-point dog ON" is smaller than the deceleration distance
from the " Pr.46 OPR speed" to " Pr.47 Creep speed".
A deceleration stop will be carried out if the speed is changed during the
operation and an error occurs.
(2) The following shows the operation when a machine OPR is started while the
near-point dog is ON.
Pr.50 Setting for the movement amount after
near-point dog ON
ON
1) 5)
4)
3)
2)
Near-point dog OFF
[Operation when a machine OPR is started at
the near-point dog ON position]
1) A machine OPR is started.
2) The machine moves at the OPR speed in the
opposite direction of an OPR.
3) Deceleration processing is carried out by
" Pr.39 Stop group 3 sudden stop
selection" when the near-point dog OFF is
detected.
4) After the machine stops, a machine OPR is
carried out in the OPR direction.
5) The machine OPR is completed after moving
the movement amount set in the " Pr.50
Setting for the movement amount after near-
point dog ON".
Fig. 8.15 Count method 2) machine OPR on the near-point dog ON position
(3) Turn OFF the near-point dog at a sufficient distance from the OP.
Although there is no harm in operation if the near-point dog is turned OFF
during a machine OPR, it is recommended to leave a sufficient distance from
the OP when the near-point dog is turned OFF for the following reason.
If machine OPRs are performed consecutively after the near-point dog is
turned OFF at the time of machine OPR completion, operation will be
performed at the OPR speed until the hardware stroke limit (upper/lower limit)
is reached.
(4) When a machine OPR is stopped with the stop signal, perform a machine
OPR again.
If the restart command is turned ON after a stop with the stop signal, an error
"OPR restart not possible" (error code: 209) occurs.