(3) Operations of near-point dog method and precautions
Under the near-point dog method, machine OPR completes when a zero signal is input after the near-point dog
has turned off. The following operations take place.
Operation step
Machine OPR starts upon execution of the OPR start instruction (IPOPR1(P)). The axis accelerates from the bias speed
1)
at start to the OPR speed in the OPR direction over the OPR acceleration/deceleration time and moves at the OPR
speed.
The axis starts to decelerate upon detection of turning on of the near-point dog. The axis decelerates to the creep speed
2)
and moves at the creep speed thereafter.
When the first zero signal (signal for outputting one pulse per motor rotation) is issued after the near-point dog has
3)
turned off, the LCPU stops outputting pulses and outputs a deviation counter clear signal to the drive unit.
Upon completion of output of the deviation counter clear signal (output for 10 ms), the Axis 1 OPR completion (SM1843)
4)
turns on and Axis 1 OPR request (SM1842) turns off.
V
OPR start instruction
OFF
execution command
Axis 1 OPR request
(SM1842)
Axis 1 OPR complete
OFF
(SM1843)
Standby (0)
Axis 1 operation status
(SD1844)
Axis 1 movement amount after
Unfixed
near-point watchdog ON
(SD1848, SD1849)
Axis 1 current feed value
Unfixed
(SD1840, SD1841)
Description of operation
1)
Near-point
watchdog
ON
Zero signal
Movement amount after near-point
watchdog ON *1
Deviation counter clear signal
ON
ON
Returning to OP (3)
(Updated according to the movement)
0
(Updated according to the movement)
CHAPTER 7 POSITIONING FUNCTION
t
2)
OFF
3)
Set the near-point watchdog OFF position as close
to the center of zero signal length as possible.
If the near-point watchdog turns off in the zero
signal state, the OPR stop position may change by
one servomotor rotation.
One motor rotation
3)
Output time 10ms
OFF
4)
ON
Standby (0)
*1 value
OP address
7
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