Mitsubishi Electronics AJ65BT-D75P2-S3 User Manual

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Appendix - 51 
MELSEC-A
APPENDICES 
 
Trouble type 
Questions/Trouble 
Remedy 
No.
Error compensation 
The machine only moves to 
"10081230", although positioning 
with a command value of 
"10081234" carried out.   
How can the error be 
compensated?  
The following values are currently 
set. 
 
Pr.2   No. of pulses per 
rotation = 8192 
 
Pr.3  Movement amount 
per rotation = 8000 
Reset  Pr.3  and  Pr.2   in the following order.   
1)  Calculate "8192/8000 
 10081230/10081234".  
2)  Obtain the reduced value.   
3)  Set the numerator in " Pr.3   Movement amount per 
rotation", and the denominator in " Pr.2  No. of 
pulses per rotation". 
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Zero point return 
When carrying out a count 
method machine zero point 
return, the message "Leave 
Sufficient Distance From The 
Zero Point Position To The Near-
Point Dog OFF." appears. Is there 
a problem 
if the distance is short? 
The near-point dog must be set to turn OFF at a position 
after the zero point is passed.   
(When the machine zero point return is started on the 
near-point dog ON in a count method machine zero point 
return, the machine enters a normal machine zero point 
return operation after returning to the near-point dog OFF 
region.) 
(If the near-point dog is turned OFF before the zero point, 
and the machine zero point return is started between the 
near-point dog OFF position and the zero point, the 
machine will mistakenly interpret that its current position is 
before the near-point dog ON position, and it will pass 
over the zero point and continue moving.) 
21
In the near-point dog method 
machine zero point returns, the 
stop positions are not uniform. 
Carry out the following measures.   
1)  Separate the near-point dog signal and zero point 
signal detection positions.   
2)  Lower the values in " Pr.48  Zero point return 
speed" and " Pr.49  Creep speed". 
3)  Confirm whether the zero point signal and near-point 
dog signal turn ON normally.   
4)  Check that there is no play (backlash) in the machine 
system. 
22
Can the machine zero point return 
be carried out with the zero point 
return retry function when it is 
started with the near-point dog ON 
and the upper/lower limit OFF? 
A "Hardware stroke limit error" will occur and the 
operation will not be carried out. 
(The machine will interpret any position where the near-
point dog is ON as being within the working range, and 
that the upper/lower limit is ON.) 
23
Are ABS and INC positioning 
possible without carrying out a 
zero point return? 
They are possible. 
In this case, the position where the power is turned ON is 
handled as the current feed position "0". 
24
After a zero point return, the zero 
point return request flag 
sometimes turns ON for no 
apparent reason. 
The zero point return request flag turns ON in the 
following cases.   
1)  When the remote station READY signal turns from 
OFF to ON. 
2)  When a machine zero point return is carried out.   
3)  When the drive unit power is turned OFF. 
If no problem is found when the above are checked, then 
it is possible that the communication is being interrupted 
by "a fault in the cable", "noise influence", etc. 
25
The zero point return complete flag 
(RX(n+2)0, RX(n+5)0) sometimes 
turns ON when it shouldn't be ON.
Check whether the drive unit READY signal is weak or the 
power supply is unstable. 
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