Mitsubishi Electric MELSEC-LD77MS2 User Manual page 453

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) The error "Count method movement amount fault" (error code: 206) will occur
and the operation will not start if the "
near-point dog ON
OPR speed
(2) If the speed is changed to a speed faster than "
change function (refer to "13.5.1 Speed change function".) during a machine
OPR, the distance to decelerate to "
depending on the setting value of "
near-point dog ON
fault" (error code: 206) occurs and the machine OPR is stopped.
(3) The following shows the operation when a machine OPR is started while the
near-point dog is ON.
4)
3)
ON
Near-point dog OFF
Fig. 8.9 Count method 2) machine OPR on the near-point dog ON position
(4) 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.
If a sufficient distance cannot be kept, consider the use of the OPR retry
function.
(5) When the stop signal stops the machine OPR, carry out the machine OPR
again. When restart command is turned ON after the stop signal stops the
OPR, the error "OPR restart not possible" (error code: 209) will occur.
" is smaller than the deceleration distance from the "
" to "
Creep speed
Pr.47
". In this case, the error "Count method movement amount
Pr.50 Setting for the movement amount
after near-point dog ON
1) 5)
2)
8 - 13
Setting for the movement amount after
Pr.50
".
OPR speed
Pr.46
Creep speed
Pr.47
Setting for the movement amount after
Pr.50
[Operation when an 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 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 "
Setting for the movement amount after near-point
".
dog ON
Chapter 8 OPR Control
Pr.46
" by the speed
" may not be ensured,
Pr.50