424 Servo alarm: Y axis detect error

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02-13-2010, 01:41 PM
padobranac

424 Servo alarm: Y axis detect error

VMC (Kia KV25), Fanuc 0M

Machine was working normally.
Suddenly, it started to give next alarms (in different combinations):
426 SERVO ALARM: Y AXIS DISCONECT
401 SERVO ALARM: (VRDY OFF)
421 SERVO ALARM: Y AXIS EXCESS ERROR

It happened while moving Y or X axis. Not every time.

Now, I can not move Y axis.
When I try to, I hear buzzing from motor (load?), it moves for few milimeters and than it crashes and gives:
424 SERVO ALARM: Y AXIS DETECT ERROR

From diagnostic 721 it says OVC (over current alarm).
02-14-2010, 05:06 PM
John_B

First, look for something mechanical. Turn the power off and see if you can move the table in Y axis by hand (requires a good amount of force).

If this is OK, look at the cables. Move the table to a different area, like if the alarm is occuring with the table forward, with the power off push it to the back (or vise versa), then power up and see if you get the alarm. This can tell you if the cables have an open connection from age and flexing.

If nothing comes to light after these two quick checks, it may be time to test the cables with a multi-meter next.
02-15-2010, 12:49 PM
padobranac

Quote:

Originally Posted by John_B

First, look for something mechanical. Turn the power off and see if you can move the table in Y axis by hand (requires a good amount of force).

I have done it before posting problem here, it moves by hand without problem.

Quote:

Originally Posted by John_B

If this is OK, look at the cables. Move the table to a different area, like if the alarm is occuring with the table forward, with the power off push it to the back (or vise versa), then power up and see if you get the alarm. This can tell you if the cables have an open connection from age and flexing.

I haven't done this, but I disconnected connector from the motor and opened it.
One wire was broken. I soldered it. While doing this, two other wires get broken. I soldered them also.
I am pretty sure I put every wire to it's position (but not 100% sure).

Now when I power on the machine, I get alarm:
400 SERVO ALARM: (OVER LOAD)
It is shown immediately after I power the NC on, even before I pull out the emergency stop button.
And it stays on all the time, after pushing reset, after power off/on...

Diagnostic no. 721 is 10000000 (OVL - overload)

Quote:

Originally Posted by John_B

If nothing comes to light after these two quick checks, it may be time to test the cables with a multi-meter next.

I probably have to do this now.
02-15-2010, 05:20 PM
alexfanuc

Question

Quote:

Originally Posted by padobranac

I have done it before posting problem here, it moves by hand without problem.

I haven't done this, but I disconnected connector from the motor and opened it.
One wire was broken. I soldered it. While doing this, two other wires get broken. I soldered them also.
I am pretty sure I put every wire to it's position (but not 100% sure).

Now when I power on the machine, I get alarm:
400 SERVO ALARM: (OVER LOAD)
It is shown immediately after I power the NC on, even before I pull out the emergency stop button.
And it stays on all the time, after pushing reset, after power off/on...

Diagnostic no. 721 is 10000000 (OVL - overload)

I probably have to do this now.

Do you have the motor part number? it should start with A06B-XXXX-BXXX
Also, Do you have the axis part number? if it is a 0C control then the number should be something like A16B-2200-0360 or 0390 or 0220.
If the table moves easily by hand then you have a problem either with the motor , the cable or the axis pcb.

Regards,
Alexfanuc
02-15-2010, 07:27 PM
padobranac

Quote:

Originally Posted by alexfanuc

Do you have the motor part number? it should start with A06B-XXXX-BXXX
Also, Do you have the axis part number? if it is a 0C control then the number should be something like A16B-2200-0360 or 0390 or 0220.
If the table moves easily by hand then you have a problem either with the motor , the cable or the axis pcb.

Regards,
Alexfanuc

I checked the cable again. One wire was broken again, I soldered it.
Again checked cable with multi-meter, everything is OK.

Now there is no OVER LOAD alarm, after power on I can move X and Z without problem.
Y axis is movable for aproximately 2 mm.
On both edges of this stroke of 2 milimeters, it starts to buzz very loud and if I move it further, it crashes with alarm
424 SERVO ALARM: Y AXIS DETECT ERROR (over current alarm)

I tried to change X and Y motor and encoder cables on the axis pcb (amplifier) and again the same thing (with real Y axis).

So the problem is not with pcb (servo amplifier).
And cable is OK too.

Obviously the problem is with motor or pulse coder.

I am now going to try to clean the encoder.

BTW, motor is A06B-0313-B006
pcb for this axis is A16B-1200-0800
master PMC-M is A16B-1211-0901 B
02-15-2010, 07:57 PM
dialog_11

Hi,
assuming everything is fine at the control side
1) check all wires/connectors on motor again often the solder points look fine but the
cable itself barely holds contact, move all cables.
2)Clean connector contacts
3) Clean motor and check motor coles
3) Upon reassembling the motor, be careful not to get the cables into/onto the runner/axis
and make sure you get everything back together having the right orientation (made that error once myself).

I had most of the mentioned alarms myself on a fanuc 6mb, and it was always down to bad cable/connection or cole issues.

I am not a pro though.
02-15-2010, 08:34 PM
alexfanuc

cable swapping

Quote:

Originally Posted by padobranac

I checked the cable again. One wire was broken again, I soldered it.
Again checked cable with multi-meter, everything is OK.

Now there is no OVER LOAD alarm, after power on I can move X and Z without problem.
Y axis is movable for aproximately 2 mm.
On both edges of this stroke of 2 milimeters, it starts to buzz very loud and if I move it further, it crashes with alarm
424 SERVO ALARM: Y AXIS DETECT ERROR (over current alarm)

I tried to change X and Y motor and encoder cables on the axis pcb (amplifier) and again the same thing (with real Y axis).

So the problem is not with pcb (servo amplifier).
And cable is OK too.

Obviously the problem is with motor or pulse coder.

I am now going to try to clean the encoder.

BTW, motor is A06B-0313-B006
pcb for this axis is A16B-1200-0800
master PMC-M is A16B-1211-0901 B

Hello:
The command cable goes from the control side (axis pcb should be A16B-2200-0360 or 390 or 220 ) to the amplifier pcb A16B-1200-0800. From this amplifier you should see 6 cables going to X and Y motors. The feedback ( encoders) go back to the control, again to the axis pcb.
If you would like to see where the problem is then you should swap the command and the feedback cable at the same time. ( Considering both motors are the same number)

Regards

Alexfanuc
02-25-2010, 09:32 AM
Muthumani

Same problem i'm faced recently..
I found that Y axis servo motor had earth fault.
I repaired the motor and fitted in the machine and it is running fine.
before that u have to confirm the motor direction
(ie phase sequence of the motor)
02-25-2010, 09:34 PM
JapieK

H0(water) in the end swits.
Gr Japiek
03-02-2010, 10:44 PM
M_Controls

The prob you are having padobranac can happen on two conditions:
A. Bad encoder feedback.
B. Bad linear scale feedback.
And, if you only swapped the X&Y motor and encoder feedback, and you also had a linear scale, then your troubleshooting is flawed. You would have to either swap the X&Y scale input as well, or turn it off in the parameters. If you don't have a linear scale (Fanuc systems usually do), then ignore this part after "A".
07-12-2010, 03:58 PM
philter

Quote:

Originally Posted by John_B

First, look for something mechanical. Turn the power off and see if you can move the table in Y axis by hand (requires a good amount of force).

If this is OK, look at the cables. Move the table to a different area, like if the alarm is occuring with the table forward, with the power off push it to the back (or vise versa), then power up and see if you get the alarm. This can tell you if the cables have an open connection from age and flexing.

If nothing comes to light after these two quick checks, it may be time to test the cables with a multi-meter next.

John B
So what if you can't move the table by hand? I could a little bit but now it doesn't move at all
07-13-2010, 04:06 AM
John_B

Quote:

Originally Posted by philter

So what if you can't move the table by hand? I could a little bit but now it doesn't move at all

Pull the way covers back and turn the ballscrew by hand.