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Alarm 401 (VRDY OFF)

Posted: Mon 05 Dec , 2011 13:24 pm
by pisit
Hello everyone
I have some problem about CNC machine. It's use FANUC control. The message on monitor is
401 SERVO ALARM : (VRDY OFF) .
I tried to check follow other method from another posted but can't finish.
The limit switch of each axis out of pressed. Overload all in machine not trip.
The AC voltage are complete. I turn on back switch and press on switch at control panel it's stay alarm.
The system not work and can't press another switch. ( problem happen after machine error spindle stop between feed.After that the technician press panel for home X Z and B axis then turn off and turn on again the machine alarm 401)
Would anyone have the method please to me.
Thank you for every reply.

Re: Alarm 401 (VRDY OFF)

Posted: Tue 06 Dec , 2011 9:47 am
by Denford Admin
Have you checked all the drives for error LED indicators ?
There are sometimes circuit breakers built into the fanuc drives themselves so check those...

I'm pretty sure this will be to do with the X or Z axis drive having tripped out, have no power, a broken or loose wire in the control cables or have blown a thyristor unit (in which case you should see an over current or overload LED indicator on the drive.

Re: Alarm 401 (VRDY OFF)

Posted: Wed 07 Dec , 2011 4:34 am
by pisit
Thanks for reply me.
I checked the servo drives and replaced servo box from good machine.
It's appear alarm. Now I try to check step by step but I don't know about step of that.
I'm not sure the spindle box have signal (ready) sent to PMC before machine start?
What's the signal that machine need before start work?
Where the ready signal come from?
Do you have another way or step to use repair this machine?
Please reply to me, I will follow your comment.
Thank you for your reply.

Re: Alarm 401 (VRDY OFF)

Posted: Wed 07 Dec , 2011 8:05 am
by pisit
.......The LED indicator on servo module showing +5V only.
Other LED not show.

Re: Alarm 401 (VRDY OFF)

Posted: Wed 07 Dec , 2011 9:45 am
by Denford Admin
The way VRDY signal works depends on the type of control and drives - 0-A used relays fitted by the machine builder for enable and error signals and a 0-C would use the signals from the drives via the Honda connector.
What machine is it ?
Do you have the original electrical drawings, machine serial number etc.. ?

Re: Alarm 401 (VRDY OFF)

Posted: Wed 07 Dec , 2011 10:44 am
by pisit
The machine is Miyano's brand from japan but it's very old model. The control use FANUC OT series.
I use manual model(BNC-12S,BNC-20S,BNC-30S) for guide to repair.
Some point of machine had modified example the spindle 2nd not used.
Now I checked switch detect point on machine(about doorcheck, oilcheck, air check, fire extinguiser check)
Then adjust or turn to same good machine static but turn on machine appear alarm.
I would like to know about parameter and diagnostic for this alarm way. In the manual doesn't have.
Please let me know if you have the other way for me
Thank you for your support.
Best Regards.

Re: Alarm 401 (VRDY OFF)

Posted: Wed 07 Dec , 2011 10:55 am
by Denford Admin
This post describe the vrdy alarm in detail and looks like it's come from a Fanuc maintenance manual:
viewtopic.php?f=4&t=3413

Is the control type 0-T model A,B or C?

I'd do an internet search for manuals that will be relevant, there will be Maintenance manuals for control/drives/parameters and connection manuals and drive connection / maintenance manuals. We can't publish any of the older manuals.
eg Fanuc book number 61395e is Fanuc 0M 0T C Maintenance Manual

Re: Alarm 401 (VRDY OFF)

Posted: Wed 07 Dec , 2011 12:36 pm
by pisit
The control is FANUC OT-B.
Servo drive 3 axis in one module.
Spindle module Fernic 5000 m.
........Tomorrow I will back to check again.
Thank you.

Re: Alarm 401 (VRDY OFF)

Posted: Sat 10 Dec , 2011 9:11 am
by pisit
Sorry for slow come back.
Today the service engineer come to repair the machine.
He use ladder manual book for check the problem.
I will learn from him today.
If finished I will result present again.

Re: Alarm 401 (VRDY OFF)

Posted: Mon 09 Jan , 2012 6:45 am
by pisit
Sorry to not reply I have many troble .
But in this problem was cleared The power of servo box fail to 65 VAC.
Cause of connector is broken. (110 VAC)