Hi all
As said in the title, we have a Mori Seiki MV-55 machining centre with a FANUC 6M-Model B NC controller. My boss bought it from a manager at an old company he used to work for, and since before I started working here he has been having trouble getting it going.
The problem was that a 420 alarm for the Y servo was being triggered. He has had a technician in and both the main NC board and the servo driver have been replaced, and in the end the technician was certain that it was the pulse encoder malfunctioning that was giving the error. After installing the new encoder the same error was appearing.
Steps to solve the alarm for 420 given in the maintenance manual were followed to no avail. We have tried setting the parameter 75 to 10000 instead of 500 as per the instructions in another thread on this forum, but this ended up giving a 422 alarm.
At the advice of the technician we tried mechanically disconnecting the encoder and turning it while the NC controller was on the see if the table position changed. We couldn't get any feedback from either the x or y axis (possibly because the machine will not provide feedback in that state).
One issue that arose from this was that if the machine was started with the Y axis encoder disconnected mechanically the Y axis would jump forwards towards the front of the machine. This resulted in the machine getting stuck on the Y over-travel switch, and I had to reverse the armature connections to the motor and jump it back off the over travel in the same way.
I personally tested the cable to the NC board and found it to be electrically sound (no shorts or discontinuities). I then swapped the "new" encoder that was sent to us (which we were beginning to suspect was buggered) with the encoder on the X axis servo. No dice. Same 420 or 422 error for the Y axis, depending on the contents of parameter 75.
One thing I did notice was that with parameter 75 set to 500 the DGNOS value 0801 would go to -500 when the machine was started an then give a 420 error, and when parameter 75 was set to 10000 DGNOS 0801 would go to approximately -2400 before the 422 error appeared. In both of these configurations, DGNOS 0804 was stuck at about 3420 and varying up and down by 10s rapidly. DGNOS 0800, 0802, 0803 were all 0. I have not been able to locate a list describing the DGNOS parameters. There are no error lights appearing on the Y axis servo drive board.
We are at a loss. We cannot figure out what could be causing this, as we have tested everything we can think of.
If anyone has any idea what could be going on we would seriously appreciate some feedback. Thanks.
EDIT1: Forgot to mention, when the NC system is powered on the CRT screen displays "bubble read" then "not ready" and just sits like that.
As said in the title, we have a Mori Seiki MV-55 machining centre with a FANUC 6M-Model B NC controller. My boss bought it from a manager at an old company he used to work for, and since before I started working here he has been having trouble getting it going.
The problem was that a 420 alarm for the Y servo was being triggered. He has had a technician in and both the main NC board and the servo driver have been replaced, and in the end the technician was certain that it was the pulse encoder malfunctioning that was giving the error. After installing the new encoder the same error was appearing.
Steps to solve the alarm for 420 given in the maintenance manual were followed to no avail. We have tried setting the parameter 75 to 10000 instead of 500 as per the instructions in another thread on this forum, but this ended up giving a 422 alarm.
At the advice of the technician we tried mechanically disconnecting the encoder and turning it while the NC controller was on the see if the table position changed. We couldn't get any feedback from either the x or y axis (possibly because the machine will not provide feedback in that state).
One issue that arose from this was that if the machine was started with the Y axis encoder disconnected mechanically the Y axis would jump forwards towards the front of the machine. This resulted in the machine getting stuck on the Y over-travel switch, and I had to reverse the armature connections to the motor and jump it back off the over travel in the same way.
I personally tested the cable to the NC board and found it to be electrically sound (no shorts or discontinuities). I then swapped the "new" encoder that was sent to us (which we were beginning to suspect was buggered) with the encoder on the X axis servo. No dice. Same 420 or 422 error for the Y axis, depending on the contents of parameter 75.
One thing I did notice was that with parameter 75 set to 500 the DGNOS value 0801 would go to -500 when the machine was started an then give a 420 error, and when parameter 75 was set to 10000 DGNOS 0801 would go to approximately -2400 before the 422 error appeared. In both of these configurations, DGNOS 0804 was stuck at about 3420 and varying up and down by 10s rapidly. DGNOS 0800, 0802, 0803 were all 0. I have not been able to locate a list describing the DGNOS parameters. There are no error lights appearing on the Y axis servo drive board.
We are at a loss. We cannot figure out what could be causing this, as we have tested everything we can think of.
If anyone has any idea what could be going on we would seriously appreciate some feedback. Thanks.
EDIT1: Forgot to mention, when the NC system is powered on the CRT screen displays "bubble read" then "not ready" and just sits like that.
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