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08-04-2009, 11:16 PM #1
Fanuc Alarm 424 Definition needed please.
Iím hoping some one can lay their hands on a Fanuc Alpha servo maintenance manual, and give me the blurb for a # 8 alarm on the Led on that drive.
Iíd normally have that manual, but Iím away in the bush about 4 hours from town. Here doing some thing else and got roped into this as well.
I have a Deawoo Puma 250 Lathe 1998 , Fanuc OT-C control, A06B-6079-H106 Single axis Alpha Servo module.
As soon as the control comes up, I get a ď424 Servo Alarm - Z axis Detect errorĒ and a 401 ďServo Alarm (Vrdy Off)Ē. Iím convinced the 424 is the real alarm, as the 401 clears with reset. The 424 is solid.
When I read the alarm code on the drive module its self, it is showing a # 8. Can any one reach for a manual and give me the definition of that? This comes up virtually instantly I push the machine ready button. And stays there.
Iím thinking its to do with the drives its self. Iíve checked and cleaned the encoder feed back side. Thatís all spotless. I get different alarms when I leave those disconnected.
The Number 8 alarm even stays there with the motor connections disconnected from the bottom of the drive. Iíve got no chance of swapping motors or servo modules, as the X and Z are different.
Input voltage is good, DC bus voltage is in spec, 24 volts is good, both fuses on the module are fine. Iíve had the drive out and pulled the covers. It all looks clean, nothing obvious blown. Transistors look O.K
I believe that maintenance manual is B-65162. Can I please get a explanation of what a #8 alarm is?
If anyone happened to have that in PDF, that would be even better.
08-05-2009, 02:12 AM #2
Phil,don`t have the servo manual here,but the Fanuc OT-C manual describes alarm 424 as
"An alarm has occurred in the Digital Servo system of the Y (M) or Z (T) axis.The details of the error are output to the DGNOS No 721.Digital servo system alarm"
Sorry that`s all I have.
08-05-2009, 03:29 AM #3
Thanks for the feed back. With the Limited amount of manuals here on site. I found some thing like that. Iím back in the hotel after dinner now. So Iím going from memory. Diagnostic 721 was 00010000. Iíve no information here as to what they would mean. There was also a bit showing on the Servo / Tuning /Monitoring page. Those pretty much just report back, what the drive alarm is spitting out.
I have a memory that on the older analog drive with the 4 led alarm lights that a #8 was an Over voltage of some sort. Iíve checked every voltage I can think of, and itís still NFG
08-05-2009, 06:56 AM #4
Phil,on other Fanuc servo drives,Alarm 8 is usually "Power supply voltage is too high".
Another manual adds "AC power exceeds 10% of the rated value." This adds "+24v overvoltage"
Don`t have an OT-C here or could have looked at Diag 721.Only got OT-A`s and OT-B`s.
08-05-2009, 09:53 AM #5
My 0T-C manual says 424 is regenerative discharge circuit alarm.
Can't find my alpha series manual.
08-05-2009, 10:05 AM #6
Alphonso,that`s interesting.Totally different description from my Fanuc manual.What number is yours?
08-05-2009, 12:09 PM #7
I have about eight Alpha manuals, the closest I have is GFZ-65165 which is Alpha motor control maintenance manual applied to 0T-C.
But it does not specify any of those codes?
I know Fanuc has so many variation of motor/encoder combinations and some faults depend on what the system has, component wise.
The older system 424 was a Z axis disconnect error.
08-05-2009, 02:50 PM #8
Been a while, I do not have your e-mail addy on my laptop and I'm on the road. PM me you e-mail address and I'll send you the PDF of the manual you listed.
08-05-2009, 03:10 PM #9
P.M Sent. I should have listed it any way. I thought me email was in my profile. That must have been the old software.
email@example.com for any one else.
Only 8.00 am Thursday morning down here. I have a few other fires to put out, then I'll get back to this this afternoon.
Hopefully Daves manual will shed some light on it.
08-05-2009, 03:21 PM #10
You got mail
08-05-2009, 04:15 PM #11
08-05-2009, 04:31 PM #12
No where does it list those alarm codes that I could find. it just says to refer to the maintenence manual. I dont know what manual number that is.
08-05-2009, 04:38 PM #13
Hey Phil, I'm on it. I'll dig through and send you what I think will help. Give a few minutes and I'll send them.
On the bright side you now have another manual for some light reading
08-05-2009, 04:47 PM #14
Just sent you two that may help. I have an alpha maint manual that is a 68 Meg PDF also. Once I figure out how to compress it, it will be on the way also.
08-06-2009, 04:34 PM #15
Sorry for not getting back to yesterday. I’d meant to do that from the hotel last night. But I walked out of here and left my laptop behind.
Dave was good enough to send me the right maintenance manual. Another mate of mine from Melbourne, found an online version on the GE site. This is the same as the one Dave sent me, I could use a second opinion, if any one wanted to down load that. Its only 276k.
This must be an old trick for young players. What I’m seeing on the drive and calling a number 8 alarm. Once I’ve read the manual, what I have there is a number 8. with a period or full stop, beside the number. That means two different alarms.
Brief description of them here. http://fanuc.pennineuk.com/alpha-alarms.htm
An “8” led is a - L-axis over-current alarm (HCL) (Page 49 of 72, in the GE PDF)
An “8.” (With the period) is a :L-axis IPM alarm (IPML) This is the one I think I’ve got. (Page 50 of 72, in the GE PDF)
IPM would be “Intelligent Power Module” So its a fault of sorts in the drive. I’ve done all the checks on page 50 of that maintenance manual. I still have that alarm. It mentions a fan that’s not working. I’ve stripped the covers of the drive and remounted it. The fan is working, and the heat sink is cold.
When I disconnect the fan I get a number 1 of the led alarm and a 400 fault out on the control.
According to that manual, the IPM can only detect the following alarms.
“ 1 The IPM can detect the following alarms.
– Drop in IPM control power voltage
2 When the control power is separated from the main power, if the circuit breaker of the servo
amplifier is off, low DC link voltage alarm (LVDC) is detected.”
I’m thinking that there might be a suspect thermistor on the drive some place. I’m gonna take a look for that.
I did find a replacement drive in Perth, $1220 AUD exchange. I just want to be sure that this drive is cactus before I recommend to the customer to buy that.
08-06-2009, 06:24 PM #16
It mentions as you say that 8. can be caused by fan stopped, I suspect this is one that has a revolution sensor, these normally have three wire connections as opposed to the usual two.
There is a rare chance the fan may not be up to rpm or the sensor is defective.
Is there another fan available on another drive?
08-06-2009, 07:42 PM #17
It does have the three wire Fan. I looked at that yesterday, when I took of all the covers. It seems to be spinning O.K. But thatís not to say, what ever detects it, isnít faulty.
The X axis drive is smaller, but a similar style. Iíll pop the covers off that, and see if they are interchangeable.
08-06-2009, 08:06 PM #18
They are probably very similar to what Mits/Mazak uses, a pulse detected from metal fan blade keeps a watchdog timer reset, if the pulse rate drops the third pin is the output WRT fan common changes state.
08-06-2009, 09:02 PM #19
I tried that, the X axis had a smaller fan, but the wire colors, and connector where the same. Both Panaflow – Matsushita Electric.
I swapped them over. With no luck. The 8. Alarm stays on the Z drive. Just has it had been, the second you hit machine enable.
I had a bit of a suspicion yesterday about the fan, but didn’t swap them. When I leave the fan un-plugged, I get a number 1 on that led and a 400 on the control. I’m guessing that would be the same if they weren’t getting to speed.
I got excited a couple of hours ago, I thought I had found some thing. I pulled the drive apart. The PCB that the alarm led is on, goes back to the base board via a plug. That was a bit dusty, so I cleaned that up, and re-seated it a few times. That didn’t help.
I think I’m going to bite the bullet and order this replacement drive. I cant think of any thing else to check.
Last edited by machtool; 08-07-2009 at 01:33 AM.
08-07-2009, 06:24 AM #20