Mitsubishi Electric MELSEC-L LD75P User Manual page 793

Trouble type
How many milliseconds should the axis stop signal
[Y4] be turned ON for?
How can a sudden stop be selected?
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?
ABS system circular interpolation operates
Circular interpolation normally, but a vertically oblong circle results when
INC system circular interpolation is carried out.
Can the speed be changed during speed control
Speed-position switching
and position control by speed-position switching
control
control?
Even if the JOG start signal is turned ON, the
response until it turns ON is sometimes slow.
The operation is not carried out at the set JOG
JOG operation
speed, although the speed limit value has not been
reached.
When a JOG operation is attempted, an error
results and the machine does not move.
Why does the positioning complete signal turns ON
during the JOG operation?
Is it possible to count the pulses when the B phase
is set to "1", and only A phase pulses are input?
Manual pulse generator Can a manual pulse generator other than the
operation Mitsubishi Electric MR-HDP01 be used?
Can one manual pulse generator be operated
connected to several LD75 modules?
The BUSY signal is not canceled by the current
Current value changing
value changing. How can it be canceled?
The LD75 READY signal does not turn ON even
LD75 READY signal
when the PLC READY signal [Y0] is turned ON.
Is there any problem with setting an M code ON
M code ON signal signal OFF request in the next scan after the M
code ON signal ON?
Questions/Trouble Remedy
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.)
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".
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].)
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.
No. The speed for the speed control and position control cannot
be set differently.
Either of the following is possible.
1) The 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.
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.
The "[Pr.31] JOG speed limit value" may be larger than the "[Pr.8]
Speed limit value".
Review the parameters and carry out the JOG operation again.
If a value other than "0" is set for "[Cd.16] Inching movement
amount", the inching operation is carried out and the positioning
complete signal turns ON.
Confirm that the "[Cd.16] Inching movement amount" is set to "0".
Not possible.
(The LD75 counts 1, 0, 1, 0.)
Other manual pulse generators can be used if they conform to
"Specifications of Input/Output Interfaces with External Devices"
( Page 69, Section 3.4).
This is possible if the system conforms to the electrical
specifications.
The BUSY signal may remain if the scan time is long.
Use a complete signal to check whether the current value
changing has been executed.
"A parameter error" has occurred.
Confirm the error No. in the error history, and correct the
parameter.
The LD75 checks the M code ON signal OFF request every
"1.8ms", so there is a possibility that the M code ON signal OFF
may be delayed by a maximum of "1.8ms" after the M code ON
signal ON, even if an M code ON signal OFF request is set.
APPENDICES
No.
A
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
791