401 servo alarm (VRDY off)

hi,

I've Puma 6s with fanuc 0, after applying the lost parameters, i found the mentioned alarm,

could any one help me to solve that.

sting

Check your circuit breakers first in your electrical cabinet if the are all alright then check your optical cable that connects the servo drives. Here is a screen dump of your error and the actions to take.

SERV0 ALARM 401
Which Fanuc Model & Axis Drive you are using. If it is Old analog & Digital Drive, Pl. check the 100V ac to the Drive. It is always through the Emergency Relay

HI,

I have a mill with a Fanuc 0M controller. The drive hardware is siemens...

I have the 401 servo alarm (VRDY off) that is thread is about...

It all started one day after the machine was off for about 2-3 months. I had to turn it off, and back on about 8 times to get pass this 401 Error.

What is it does is upon power on, I hear one relay.. the screen shows some software numbers, and then jumps to the XYZ 00000 screen like it always had before, but now, it sits there about 5 seconds like it wants to work, but I hear another relay trip and up comes the 401 servo alarm.

I have looked at the parameters, but I really do not know what they are suppose to be. I purchased the machine 5 times ownership old, and no books or parameter papers came with the machine. Also, it seems that the siemens controller is not popular with people.

I have changed the motors around, and it does not help. They are all 3 the same according to the tags on them. I have pulled the controller board, and this appears ok..

There are some LED lights that come on.

First on bootup, a green LED pops on, and then back off. When the machine CRT displays the XYZ 00000 screen, all LEDs are out, and then that relay trips and a red one on the SIMODRIVE 6RB21 board lights up ( V5 ) at what appears to be the Y axis set of lights. Then the green one, and a red one comes on at V4 and V1

So, somehow I think it is the limit switches, but they are all free and I hear relays clicking. I can put some wedges in the switches like the machine is home, and the error does not come on, but neither does the machine. the boot up hangs at the software version screen and will not continue to XYZ 00000 screen. Pull the wedges, and it will continue to boot, but then 5 seconds or less, the 401 Servo Alarm....

Any ideas?

thanks

For the Siemens drive.
Check the dc link voltage at the axis drive.If it is ok,check the drive healthy signal which is 24vdc and goes in terminal 73.2 and comes out 72 or vice versa on the axis drive.If you do not have the healthy signal the problem is in the drive.These older drives do not like dampness.If they have been standing a while disused in a less than dry atmosphere it is better to give them a blow with a heater for a few minutes before powering up.

I would need a little more definition of what these items are called for a mill tech vs a master mech and computer engineer..

I call the drive axis motor.. just plain electric motors.

I call the SimoDrive a computer controller.

I call the Fanuc a user interface controller.

Now, checking the axis drive sounds to me like checking the computer controller at some test point.

The drive healthy signal at 73.2 sounds like some test point on that big cabinet where there are many wires running around.

What is a axis drive... what does not like dampness. Because I sure have alot of humidity in my shop. No heat or AC, so temp inversion is really bad some days.

Its hard for me to understand that it will boot up and sit there about 5 seconds sometimes and it wants to work, but then that relay will trip and the 401 error comes up. I can disconnect the encoder plug and get X error communication, and then take off Y and get the same error.

thanks for your help, I need to make some parts...

Fastfieros.
The Fanuc part is called the cnc control.
The Simodrive is an axis drive and/or a spindle drive.
The axis drive motors are servo motors.
I`m afraid I cannot give any more help as the voltages within these components are lethal if you come into contact with them.
I suggest you contact a cnc repair guy.
Mark.

I have had this machine for 3 years. I have worked around higher voltages than the 240 running around inside this cabniet. I wear and adhere to proper safty equipment and guidelines. I have a EE degree.

I worked with the machine some more today. I called Fanuc and they suggest the problem is in the Siemens controller area. One time today, it booted to the ready state for about 10 seconds... in the past when it did this exact same thing, all I had to do was turn it on and off about 10 times and it finally stayed in the ready state.

I think it is the 24v signal as this is what the Fanuc customer support indicated also. is it 24v DC or AC? I can remove the caps from the drive motors. I have already removed these 20 plus times. Even if it is missing 24v signal, what am I going to replace to fix this issue? I looked up all the boards in the controller.. I have the following with the XYZ conections... 6RB2100-0NA21, Control Board

From what I remember it all started when I overran the table on the x axis, and worked fine the rest of the day, but when I tried to turn it on the next time, it did not boot up to ready. it was the error....

There is a lot more than 230 volts running around this cabinet.The dc busbars will either be 210 or 320 volts.These are open and run along the botton of the axis control.
The old dc drives do not like dampness,stray voltages short on the cards and cause failure,sometimes with a very loud bang.This problem is not confined to Siemens only.
Yes the problem is in the Siemens unit.The Fanuc control is not getting a drive ready/healthy signal.It is 24vdc.It comes from where I told you.Have you checked the dc fuses feeding the stack cards?
It is possible to remove axis cards and make the drive think there is only one or two axis but you need to know what you are doing.
If you have elec schematics for the machine you will be able to follow this signal if you are an EE.
If the fault is not obvious to me I have spare cards and can replace each card until I find the faulty one.I also isolate the Simodrive from the cnc and set each axis up using a battery box.It is relatively easy to do as Siemens always uses the same terminal numbers from drive to drive.
What make is the mill?

No schematics to the machine : ( I am about number 5 owner... I purchased the machine without parameters even loaded. I was lucky enough to fine a phone number on a piece of paper in the machine that was for AIT in CA.. Sidney was the person who built the machine in 1989... it is a WebbMatic 800 with this lovely Fanuc Om-A and the Siemens controll.

Sidney sold me the parameter sheet, and I loaded the machine and got it working. It never has zero home correctly since I have had the machine, but my work is not that precision, just needs to look pretty.. The machine is very tight, so I would like it to work a little more. The spindle head is nice, and not noisy..

BTW... here is some of my work http://www.fastfieros.com/projects

I am a hybrid engine installation specialists.. but I did computer networking and systems testing in the past also.

You can download a manual for the 6RB2100 drive at the Siemens Automation and Drives website.It is a nightmare site to navigate but can be done.
Mark.

http://www.fastfieros.com/host/milllights.jpg

here is a pic of the inside... I marked the LED's that are on with the red arrows.

http://www.fastfieros.com/host/millfuses.jpg

here are the fuses... all of these are confirmed good.

Hey gridley51

Can you help me a little more here.... please....

I downloaded the manual on the 6100... I studied 73.2 and somewhat understand how it works...

I read the voltages at G0 card on these pins....

Ok, 9 and 63 are at the top... and they are jumped together with a green wire.

9 = 17.3 V
63 = 17.3 V
64 = 33 V
73.2 = 16 mV
72 = 20 V

I read that 73.2 should be the same as 72 if all was working right. I cannot tell what is bad however. The relay K22 is clicking it sounds like.

I even jumped 72 and 73.2 together to see what happens, and it clears the 401 error, but I get a 404 error with that jumper, and it reads VDRY = ON with that. So, I removed my jumper, and back to 401...

thanks......

9,63 and 72 are a bit low for 24vdc.I will need to check the allowable specs but you have over 20% voltage drop there.
I would expect 0v on 73.2 if the drive has a fault.
I can`t remember what 63 is,I suspect it should be 24vdc also.Will have to check tomorrow.
What is the dc link voltage at?

Well, after reading and reading these block diagrams, I can not figure out where DC link is in my cabinet..

the paper reads....

L to master switch

Something that is X501 ( I cannot find a X501 anywhere )
Then to K1 ( relay, I cannot determine what is or where )

Then to N

K1 on the other page is at the big relay with L1 L2 L3... and then PE

Now, L1 is 120v AC , L2 is 120v AC , L3 is 220v AC

then this goes to K2...

Then it shows that K2 has something to do with Board G0 at X121... now I know where this is, and pins 9 and 63...

So, it looks like K2 relay closes, and provides power to U V W ... it appears that this is 165v AC at U V W ....

What is the point of DC Link you want me to find?

Are you reading L1,L2,L3 coming out the transformer?If you read L1-L2,L1-L3 and L2-L3 you should have near enough even readings.The 165vac gets rectified to 210vdc and this is linked across the amplifier cards in the axis drive.This 210vdc is what is known as the link voltage.The amplifier cards are also known as stack cards.It is going to be difficult for you to fault find without substituting boards.Give your boards to a Siemens repairer to check for you.Most of them have racks set up and can put your boards in one at a time to test.While the boards are getting tested check the brushes in each servo motor and while the brushes are out give the carbon a blow out with dry air from an airline.If any brushes are worn well down or chipped and broken inspect the commutator as well.It is ok to pull these motors apart but do not leave the rotor out the stator for long or you will lose magnetism.I usually check the motors on there own on a 12v truck battery.They should run nice and smooth in both directions which you can do by reversing the leads.If they run smoothly at 12 volts I have never had one fail at higher volts although sometimes I will connect them to a battery pack on an electric forklift where I can select up to 72 volts.
Mark.

Ok, I have found what you want me to measure..

it is identified as

X1 = 156v AC
X2 = 203v AC
X3 = 175v AC

at the rectificer output to the capacitor is 307v DC

not a very stable 165v and the output of the rectifer is high compared to 210v DC you mention, but I cannot find on these block diagrams many voltages I am suppose to see..

Attached a pic of that transformer.. the yellow ones on the left are the ones going to the rectifier..

I have a little more info today..

I found a blown fuse on number one...

Number 1,2,3 go to an Allen Bradley relay 100-A09NA3 Ser B

then from there is 8,9,10 to the drive transformer..

this AB relay is buzzing today. I changed the number one fuse and tested the one I put in there for continuity, and sure enough, upon power up, it must have blown that good fuse, because it now does not have continuity.

Is this relay bad since it is buzzing?

Is the transformer bad causing the buzzing, and blowing the fuse?

Is the fuse before or after the transformer?
The buzzing is either caused by dust/muck on the pole faces of the contactor or the coil voltage is low or lastly the coil is faulty.It`s most likely to be on of the first two.

the fuse block is right after the master switch.

1,2,3 go to the fuse number 1, 2, 3... then the output is 8, 9, 10 to the AB relay.. then the output is to the drive transformer. This is making the drive transformer not getting the correct input voltage so the out put voltage is correct. ( i think )... well, at least the output to the SimoDrive, and the SimoDrive is showing the error.

Either that transformer is bad or that relay is bad it seems like to me. I have heard that AB relay in the past do some strange noise things.

I cannot find a part number on that transformer to even begin to try and track one down.

If the transformer was bad it would blow more than one fuse.With the power cables disconnected from the relay and the power off close the relay by hand and measure the resistance across the line contacts.Reading should be very low and same for all three.If not toss the relay.
What does EE stand for in this degree you have?

Hi everyone.

I have the same problem with my machining center. It has a Fanuc 0m control and the 401 servo alarm (VRDY OFF) message comes right at machine startup. I just bought the machine and the seller said there was no alarms before they disconnected the hydraulic unit. After they reconnected the hyd unit, the message appeared. He said that it's probably because theres air in the oil system but I doubt it. Besides I have let all the air out of the oil tubes.

The machine starts normally but after a few seconds a relay clicks and this message appears. I measured some voltages from the power unit module and found out that the module does not have power because the main relay does not work, uknow the really big one right after the main power switch and transformer that is driven by the power unit itself. I manually pressed the relay so that all the modules had power but it had no effect whatsoever. The same 401 message appears. :confused:

The servo- or the spindle driver's alarm leds are not lid, but the spindle driver has been changed to a re-built one so im not 100% sure if theres some compatibility problems. But the driver is not broken, it is guaranteed, and there was no alarm when the driver was changed, it appeard later.

Also no axis limits are pressed because none of the axis are close to the ends and I can hear a relay click by pressing emergency button, and the electric charts say the limit switches are serial connected to the emergency button.

Any ideas, anyone?

Hello. I don't know your particular machine but i can tell you that the VRDY alarm means you dont have the 300 volts on the buss power for the drives. The buss power is the large shinny chrome bars that connect between the drives. Your drives are powered by a power supply. Check your power supply for proper voltages in and out and see if you have a power boot up sequence in your manuals so you will know in what order and when things are powered up in the start up sequence.

There are full voltage at the power buss when the main relay is manually pressed. But the relay does not connect by itself. But although there are power at all drives, the alarm still appears.

Still having the same problem... A couple of professionals have had a look at the machine but so far no progress.

I've studied the ladder diagrams and tried to find something that would cause the power module not to connect the main relay. So far I've discovered that all the axis limit switches do work but none of them are pressed, spindle gearbox switches work, emergency button works, spindle and gearbox lubrication works, hydraulics work...

What I would like to know is that does the power module get some kind of information from spindle or axis amplifiers so that this unleading main relay could be a result of some kind of accessory failure or some other fault? If not, the power module has got to be broken because the only input that it gets via a separate cable is the one from emergency button. And i've measured that it works fine.

Improper grounding can also cause this problem. Does this machine have it's own seperate ground or is it grounded with other machines?

It has its own ground, it is connected to the main grid via a 5-wire cable, 3 phases, zero and a ground. Also the phases are in correct order, and just in case I've tried to run the machine also with reversed phase order.

Have you checked you servos, power supply and spindle amp to make sure all the boards and cable are pushed in (connected) properly?

Yes, I have checked all the connections and every single fuse I could find in the machine. I've also opened the power- and spindle module and inspected if there are any black burned spots in the circuit board or swollen capacitors or something unusual. I found none. :/

Could someone with similar milling center test their machines that is the main relay supposed to be connected and the power unit supposed to feed voltage to the crome bars, if the spindle amplifier and axis amplifier are completely disconnected from the power unit?

This would help me a lot because if there should be power feeded from the power unit, despite if the amplifiers are disconnected, it will narrow my problem down to the power unit itself.

The machine is now up and running! Turned out there wasn't anything really busted in the machine, the previous owner had just disconnected the rotating a-axis and this machine needs some kind of blind cable or termination resistor or something like that to the connector that used to lead to optional a-axis servo module. And also he had messed with the parameters and hadn't taken backups so we did need an expert to straighten them out. Who knew that the missing axis caused the main relay to not conduct, I was so sure that the power unit was busted.

I'm not really having any luck either; same alarm, both 401 & 402 - x axis and z axis. Above those 2 alarms it also says something like - 1000 something monitoring something:3 . Whatever that means??? I was just there helping the Fanuc 210i-T control, get its memory back (this machine is an old Colchester Clausing Lathe w/a Combi control, built back in 1999); who would have known - you can pull the monitor panel out and connect a keyboard and mouse up to it, to help out... Yeah, so I cleared up the memory problem, but it keeps coming up with these alarms. The Polish guy that works it did a thing inside the back cabinet. By turning off the machine like normal, then pull a jumper in the back cabinet and move it over to the off position, then turn the machine back on (only in back -not the front panel on button), and watch the little code display under the jumper. When four zero's come up, push and hold the button above it. Don't let go until the display reads 2200, (the numbers on the display will read like 100, 200, 1000, etc., until it reaches 2200. Then let it go, turn off the machine, (in back again only), then pull back out the jumper and put it in the on position. Then turn on the machine in back, and then in front like normal. This is supposed to clear the alarms....but it hasn't yet for us. He swears by it!! But maybe that 1000 code means something simple, like I was supposed to take the k.b. and m back off and close up the monitor panel first, before the jumper deal. I don't know yet...I'll go back and try it again tomorrow. You wanna try it? If anyone knows anything or tries this jumper switch, and it works, you guys give me a shout back. I'll check this out tomorrow...G'nite:)

401 ALARM is 'normally' caused when the Fanuc CNC isnot getting the 24 V ready signal send via the ESP switch in the PSM



402 SERVO ALARM: SV CARD NOT EXIST (sounds like the servo card is faulty)

Hi All

This is my first post on this site but have been browsing a lot.

We have 6 fanuc robots(CNC) and resntly had same problem and found power supply -15V rail was not working. It is worth check all the voltages on the power supply card against the 0V line.

Another choice is servo amplifiers have a loop plug in the bottom and small relay contacts inside to tell cpu that amplifiers are okay. We have found this relay to cause errors and bridge out plug.

Good luck with your efforts

dear all

I've got a Kryle VMC 700C and recently encountered problems with the equipment. The first one was 401-VRDY OFF(servo alarm) , the second one was 1023-magazine failed to index and the third one was 1027-powermate Servo alarm. Through these problems the machine can neither be operated and nor can i know from where could get help on how to troubleshoot those problems.

Please send your suggestions and advices.

Regards

Ashley25

Ashley,all I can offer is to concentrate on fixing the 401 alarm and you may find the others go away.

Quote:

---

Originally Posted by gridley51

Ashley,all I can offer is to concentrate on fixing the 401 alarm and you may find the others go away.

---

To gridley51

Thanx Gridley, but it appears that the 401 VRDY OFF is intermittent and constantly when the equipment is powered ON, sometimes it appears and the rest of times it doesn't even show up.

I've tried testing across the pins 1 and 3 of the cx3 connector on the PSM, and as per the maintenance guide, the contact is shorted, which is PSM OK.

Please advise for further steps as the equipment's been inactive since long resulting in loss of production.

Regards

Ashley25