MITSUBISHI ELECTRIC Mitsubishi Programmable Logic Controller QD75D - Manual (Page 737)

Appendix - 95
MELSEC-Q
APPENDICES
Trouble type Questions/Trouble Remedy No.
The positioning start signal [Y10] is
kept ON until the BUSY signal is
OFF, but is there any problem with
turning it OFF before the BUSY
signal turns OFF?
After the BUSY signal turns ON, there is no problem with
turning [Y10] OFF before the BUSY signal turns OFF.
(The QD75 detects the rising edge (OFF
ON) of the
positioning start signal [Y10].)
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Start
The operation will not start even
when the start signal is turned ON.
Check the " Md.26 axis operation status" and
" Md.23 axis error No".
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How many milliseconds should the
axis stop signal [Y4] be turned ON
for?
The signal should be turned ON at 4ms or more.
(If possible, set the signal so it does not turn ON only
momentarily, but instead stays ON until the BUSY signal
turns OFF. This will keep the stop signal from skipping.)
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How can a sudden stop be
selected?
Set "1: Sudden stop" in the parameter from Pr.37 to
Pr.39 corresponding to the stop group, and reduce the
setting value of " Pr.36 Sudden stop deceleration time".
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Stop
"Normal deceleration stop" was
selected in " Pr.39 Stop group 3
sudden stop", and Y stop was
turned ON. If the Pr.39 setting is
changed to "sudden stop" during a
deceleration stop, and the Y stop
signal turns from OFF to ON, will
the operation change to a sudden
stop from that point?
The operation will not change.
Even if the same stop factor is input again during the
deceleration stop, it will be ignored. The same
deceleration stop process used when the stop signal was
first input will be continued.
(This also applies for Pr.37 and Pr.38 .)
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Circular interpolation
ABS system circular interpolation
operates normally, but a vertically
oblong circle results when INC
system circular interpolation is
carried out.
The address designation may be incorrect. When carrying
out INC system circular interpolation, designate the
relative addresses from the starting point of both the
center point and end point.
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Speed-position
switching control
Can the speed be changed during
speed control and position control
by speed-position switching
control?
No. The speed for the speed control and position control
cannot be set differently.
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Even if the JOG start signal is
turned ON, the response until it
turns ON is sometimes slow.
Either of the following is possible.
1) The sequence program may be incorrect. Check by
creating a test program in which the JOG start signal
is turned ON only.
2) If the machine is hitting something when the torque
setting is low, it may be trying to move by JOG
operation in the opposite direction. In this case, the
machine will start moving only after the internal droop
pulses have been reached 0 in the counter, even if the
JOG start signal has been turned ON. This makes it
seem that the response is slow.
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JOG operation
The operation is not carried out at
the set JOG speed, although the
speed limit value has not been
reached.
Either of the following is possible.
1) The JOG start signal may be chattering. Monitor the
JOG start signal to confirm whether it is chattering.
(When using the "BUSY signal" in the JOG operation
start circuit, check the position of the BUSY signal.)
2) The " Pr.31 JOG speed limit value" may not be
appropriate. Review the setting value and carry out
the JOG operation again.
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