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Mori SL200 Alarm EX0491 Spindle Speed Abnormal Help and Ideas

13engines

Stainless
Joined
Jun 30, 2015
Location
Saint Paul, MN
Greetings,

Been having this alarm pop up recently. Stops the machine cold and have to reboot. I'm running a 1" 12L14 steel bar job. A couple of the sticks are not the straightest and am dealing with some vibration. Using a Trusty Cook liner and Spego bar feed. I'm wondering if the vibration can be setting this off.

There is a proximity sensor that reads the passing of three notches cut out of the brake disc hub and is labeled spindle speed sensor in the book. It's connected directly to the PLC. Is this thing sensitive to noise and/or vibration? I see it's mounted very close and thought tomorrow I'd move it away a bit and see if it still reads okay.

After my program stalled a couple times in the higher speed sections (capped at 3000rpm) I pulled the bar out and ran it without stock and had no problems over what was three, two minute runs. With it being so intermittent thus far I'm reluctant to swear to it that I've solved the problem. I mean, was running it without stock and eliminating the vibration really fixing the problem, or was the machine simply playing nice for the time being? Hard to tell.

I can't find squat about this error either here on the www. Anyone with past experience or ideas what I might be up against? (2000 Mori SL200-SMC Fanuc 18iTA)

Thanks.
Dave
 
The EX alarms are Mori specific so you will need to look at the Mori alarm list. On a machine that vintage, the alarms may be in a Mori operation manual, but there should be a listing in the back of the ladder diagram manual. Intermittent and maybe affected by vibration makes me think bad connection or broken wire.
 
"Spindle Speed Abnormal" usually happens when the programmed spindle RPM differs from the actual RPM by a sufficient margin.

Vibration usually isn't the issue.

If the machine is stopped and you spin the chuck by hand at say, 100RPM, that can also trip the alarm.

In your case if the bar is rubbing bad, the solutions are to cut the bars shorter (you'll have more remnants), straighten the bars, or cap the RPM lower, e.g. 1500 RPM.
 
"Spindle Speed Abnormal" usually happens when the programmed spindle RPM differs from the actual RPM by a sufficient margin.

Vibration usually isn't the issue.

After reading this I wonder...

Can CSS (Constant Surface Speed) control fail to keep up with tool path position and feed commands to the extent that it would throw this Spindle Abnormal Alarm?

I had a problem on my Mori SV50 mill once where it through some kind of a servo over-taxed alarm trying to keep up with a high speed tool path that was confined to a small area and moving between G1 feed blocks during cutting and G0 rapid moves in repositioning. I had to change the program to all G1 moves with different feed rates for cutting a repositioning to correct the problem. My thought was that when the control saw GO it would dump all the energy it had into the servo while never really having the time to make it there because of the shortness of move, then trying to retreat back to feed mode. Doing this over and over it would eventually throw a fit and an alarm.

On my new to me lathe I'm wondering if I have a different version of this same problem. I'm currently running my first ever programmed G71 auto roughing cycle followed by a G70 finishing cycle. (Reference below) The entire work area of this call is confined to about 0.300 in both X and Z. It's taking about 4 or 5 quick cuts on the outer corner of 1" stock. (I'll shorten that up later) I have G50 set at 3000 rpm. The mass I'm spinning is an 8" QC chuck with hard jaws, an 8 1/2 lb. Trusty Cook plastic liner and a 6-ish foot 12L14 steel bar running in a Spego bar feed. Because these moves are very quickly passing over and over through X, is it possible that CSS isn't keeping up and throws this alarm?

I've check and reconnected the proximity cable, and I'm going to look into my parameter book and see if I can't broaden the allowable speed error range CSS will operate in. (Non critical parts in easy material) I may also slow the machine down and see if that helps although I really don't want to do that.

Here's the section of the program where it usually stops.

T0100(TURNING TOOL)
G20G40G56G80G97G98

M70(BAR FEED ON)
G0Z0.5T0101
X1.075
G98G1X1.05Z0.05F90.
G50S3000
G96S916M3
M8
G99
G71U0.05R0.05
G71P10Q20U0.04W0.01F0.01
N10G0G42X0.635Z0.015
G1Z-0.075
X1.03Z-0.2103
N20G40X1.05Z-0.2171
G70P10Q20
M9
G97S726
G53X-8.
G53Z-8.

Am I all wrong with this hypothesis? Likely cable related? Amp problems? I did run most of a bar without trouble.

See how today goes.
Dave
 
Are there any alarm codes on the spindle drive read out? It all depends but some spindle drives can spit out some pretty detailed information and others don't.
 
No numbers on the drive. They look all okay.

Screw it... it just alarmed out during cutoff too. I noticed that my SFM is high enough that the entire batch of code listed earlier is running at the G50 limit or right near it. I thought I saw it run down to 2990 once. I'm going to switch the program over to feed per minute at 3000 or try it as is with a 2500 rpm cap. Also going to dig out the parameter book. I got to get this job done and hoping my amp isn't signalling the end of its' life.

Dave

Edit - Couldn't find a parameter that set a range before alarm. Anybody knows it, I'm all ears. Fanuc 18iTA (Mori MSC501)
 
Ran into this issue a few months ago on our Mori SL-204. First we replaced the encoder. That bought us a month. Then the servo drive went. Replaced that and it bought us another couple months. Finally, we replaced the motor. Been going strong for another month now.

The EX491 alarm is what we got for both the encoder, and the servo. The motor itself was a different alarm, but I cannot remember what it was.
 
If there is a variable that can be changed it will most likely be a PMC parameter defined by Mori's ladder. Does any of your Mori documentation list this alarm? If not, or you do not have the manuals, it will take a wander through the ladder diagram to see what logic drives the alarm. From there you may be able to determine if a parameter is used to set the allowable deviation.
 
If there is a variable that can be changed it will most likely be a PMC parameter defined by Mori's ladder. Does any of your Mori documentation list this alarm? If not, or you do not have the manuals, it will take a wander through the ladder diagram to see what logic drives the alarm. From there you may be able to determine if a parameter is used to set the allowable deviation.

I don't have the ladder in print, and for me to try and follow it on the screen is beyond my brain power. I'm going to call tomorrow when this job is done and order a ladder printout and find out what their service persons' take is on this alarm.

Lowered my G50 to S2547. Thought that was arbitrary enough, and just ran a whole bar without trouble. I have a feeling my new Trusty Cook might not be the the most true running thing I've ever seen. Will check more on that later.

My proximitry sensor is less then a paper thickness away from the hub. Don't see any telltale signs of it rubbing though.

Lunch over. Back to work!

Dave
 
Not likely that anyone really cares, but capped spindle rpm at 2547 and the job ran all day.

Think my Spindle Speed Abnormal alarm is more physical than electrical.
 
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My proximitry sensor is less then a paper thickness away from the hub. Don't see any telltale signs of it rubbing though.

Don't mess with the speed sensor gap if it is .005" to .007" give or take a thou. Don't use a metal feeler gage, use plastic to check as not to damage the face of the sensor. It's a pretty small window where they will work correctly. The run-out on the pickup gear is critical too, I try to get .0002" or better run-out on those.

It sounds like a vibration problem. I copied this from the ladder so you can search those addresses.

X54.0 R1362.2 MER0491 SPINDLE SPEED ABNORMAL (EX-PC) 126-08 338-22
 
Don't mess with the speed sensor gap if it is .005" to .007" give or take a thou. Don't use a metal feeler gage, use plastic to check as not to damage the face of the sensor. It's a pretty small window where they will work correctly. The run-out on the pickup gear is critical too, I try to get .0002" or better run-out on those.

It sounds like a vibration problem. I copied this from the ladder so you can search those addresses.

X54.0 R1362.2 MER0491 SPINDLE SPEED ABNORMAL (EX-PC) 126-08 338-22

Thanks Other Brother for the warning and addresses. I'm leaning towards a bent bar pusher rod tip and so-so spindle liner running accuracy.

Yes the sensor looks closer then a guy would think it needs to be, but I didn't see any rub marks so thought I'd leave it as is. It is mounted with only a light-ish gauge sheet metal angle bracket. Wondering if the vibration could jitter it so much that it causes a severely fluctuating magnetic response and bugs-out the PLC. It would be interesting to monitor the prox sensor signal with a scope and see what vibration does to it if anything.

My ladder skills are shakey at best. Wish I could take a class somewhere and nail it down. But here's my problem with using the, or a ladder to help fix this problem. (And others in general) It's likely my ignorance about what a ladder can do for the repairman is what even allows me to write the following.

The alarm includes an R address with it which I always find useless, as all it ever shows is the imaginary coil that calls out the stored alarm message wording. I'm like... why do I care where the words for this alarm come from? Using what OtherB supplied, I take that during the alarm I would likely find X54.0, which I'm guessing is the output from the sensor, sitting high, possibly closing a wrung on the ladder that also closes R1362.2 and causes the machine to alarm out and give me a message on the screen about it. To me that's sort of like the idiot lights in old cars telling you completely after the fact that you have a problem. Other then leading you to investigate the speed prox sensor,(which I already did simply from the wording of the alarm message) it doesn't tell me anything else. In my case, sensor looks good. Must be working because most of the time there are no problems. I guess you could say the ladder has served to verify a closed switch, but now what? I suppose if I were an expert in Mori repair with a long record of messing with this alarm I'd have something to go on. But has the ladder really helped me out that much? It's likely there are machine problems that a repair person would say, "thank god there was a ladder or I would have never figured this out." But here I'm not so sure. Please... someone show me the light. I think I've done more repair/verification work watching/checking the zeros and ones in the data tables. I wonder if the best use of the ladder is if you believe the machine is hung somewhere in the middle of something. What's holding it up? There I think the ladder could show you something that could be difficult to surmise out of the blue. That is if you really knew how to read it and follow it's complete path across many pages.

Dave
 
Using the ladder to troubleshoot this is not in beginner territory.

Imagining roughly the logic in the ladder would look a bit like...

Input from the sensor at X54.0 is read by a high speed counter function
Some math is done on the counter to equate to speed units.
The result is compared to the commanded speed units.
If the difference between commanded speed versus actual speed is below some limit, keep going.
If the difference between commanded speed versus actual speed is above some limit, stop the spindle, raise an alarm and display the error message.

Reading the ladder to determine what all goes on it not likely to point exactly to the trouble in this case. There may be multiple conditions that will generate the alarm. Watching high speed inputs on the ladder is pointless as the screen delay won't let you see missing counts. You would need an oscilloscope to watch that.
 
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OP, Have you tried to Tach. the spindle in comparison to the commanded speed?

There is also a chance that the Alarm is from an over violation of commanded speed.

R
 
Hey Dave (13engines), did you ever get this resolved? I had this alarm pop up on me twice last week and am trying to get to the source of it before it grows into a bigger problem. Thanks!
 
Hi wmpy,

No I never did. I've just been keeping my G50's under 3000. The self imposed restriction hasn't hurt me terribly just yet.

Though I do have some new repeat work for it now that in part I'd like to run faster if I could, but even that idea is hampered by the fact that all the turning that I want to do at high speed would sort of be wasted effort. That's because the turning is all done in sync mode using the B axis spindle as a live tail stock. When you do that, the spindles take forever both to start and to come to a stop, as the push to start and the regenerative braking are held to 50% power and less, whereas when running one spindle it will hit 150% or more to get things starting and stopping. My point is, what good does it do to wind things up so high just to have to wait for them to wind down again. Plus I'm still running chucks with jaws, and the coolant windmill effect is already off the charts. If I didn't run a demister all the time I'd be toast.

Anyway... enough blabbering on. Please let me know if you come up with anything. I'd appreciate it very much. If I dig back into it and find anything I'll pass it on too.

Dave
 
Hi Dave. I think I figured out the problem with my EX0491 alarm. I thought I’d post it here in case this helps you or anyone else with this problem. My machine is different than yours, so it might be a different issue. Mine is a DL150Y with MSC-518 control. I believe that’s a Fanuc 18TT-C. The turning spindles are integral motor spindles.

So, the problem got a lot worse to where I couldn’t run the spindle for more than a few seconds without alarming out. Before, it had happened randomly a couple times the week before while spinning at a constant 3000 rpm- no vibration, light cut, on a job that has been running for months and made thousands of parts without issue.

I tried spinning the spindle by hand really fast to see if I could get it to alarm out as Orange Vise mentioned above. I did get an alarm, but this time it was the EX0490 alarm- not my problem.

Looking in the electrical manual, I see that there is something called “Spindle speed monitoring detection”, also referred to as “Spindle monitor”. There are four sensors- one for each turning spindle and each milling spindle. They all feed back to a Fanuc PLC which is then connected to an I/O on the control via IOLINK. These are the only connections for this PLC.

It turns out that the sensor for the left turning spindle is bad. Between the spindle casting and the disc brake, there is a ring with four notches in it. This sensor picks up that ring. It’s just a 8 mm inductive proximity sensor. It is simple enough to check with a multimeter and also by just looking at the indicator light on it. It is still working sometimes, but it’s failing enough to where I can see it working at times and other times not. I have a new prox sensor on order and will put it in early next week once it arrives. I will update then, but I expect this to fix my problem with the EX0491 alarm completely.

I really don’t understand the purpose of these sensors. These aren’t the large, expensive Fanuc speed sensors that act as a tach for the motor. I believe that the prox sensors are in addition to those. When the prox sensor isn’t working, the display still correctly shows the actual rpm. So, I don’t get the purpose for this extra check of the spindle speed.

Hopefully, this is of some help to you. If anyone can tell me what these things actually do, that would be great. I'm quite curious.
 
...It turns out that the sensor for the left turning spindle is bad. Between the spindle casting and the disc brake, there is a ring with four notches in it. This sensor picks up that ring. It’s just a 8 mm inductive proximity sensor. It is simple enough to check with a multimeter and also by just looking at the indicator light on it. It is still working sometimes, but it’s failing enough to where I can see it working at times and other times not. I have a new prox sensor on order and will put it in early next week once it arrives. I will update then, but I expect this to fix my problem with the EX0491 alarm completely.

I really don’t understand the purpose of these sensors. These aren’t the large, expensive Fanuc speed sensors that act as a tach for the motor. I believe that the prox sensors are in addition to those. When the prox sensor isn’t working, the display still correctly shows the actual rpm. So, I don’t get the purpose for this extra check of the spindle speed.

Hopefully, this is of some help to you. If anyone can tell me what these things actually do, that would be great. I'm quite curious.

Hi wmpy, well I'm certainly anxious to hear how this turns out. If I remember correctly I have one sensor that is like a puck on the end of a cord. That must be the actual speed sensor you elude to. The one you're replacing I imagine as a threaded cylinder type. I'll have to take a look. I keep the end panel off my machine to keep track of things so it will be easy to look for it.

I'm curious what you mean in relation to what I'm thinking are visual clues of the sensor light. Isn't it flashing so quickly? I mean, how are you making sense of the idea that it's not operating as it should? Visually that is. Or was it the multimeter that filled you in?

I know some machines have an M19 Spindle Orient option. Maybe the spare sensor is for that. My other guess would be it's part of the synchronized phase and/or speed feedback for doing full on part transfers between spindles.

Anyway... I'm going to scope out the wiring and connection locations, and part numbers just in case you solve this now age old dilemma. Good luck!
 
I'm curious what you mean in relation to what I'm thinking are visual clues of the sensor light. Isn't it flashing so quickly? I mean, how are you making sense of the idea that it's not operating as it should? Visually that is. Or was it the multimeter that filled you in?

I know some machines have an M19 Spindle Orient option. Maybe the spare sensor is for that. My other guess would be it's part of the synchronized phase and/or speed feedback for doing full on part transfers between spindles.

Anyway... I'm going to scope out the wiring and connection locations, and part numbers just in case you solve this now age old dilemma. Good luck!

I didn't look at the sensor light while the spindle was rotating. I think you're right that it would be too hard to notice it flashing so quickly. I just moved the spindle slowly by hand while watching for the light to go off and come on as I moved past the notches.

It could have something to do with the phase synchronization. I'm going to see if it moved once I get it running again. The part I'm making has a slot on each end that need to be 90 degrees apart, so it will be easy to find out if the phases moved at all. That doesn't explain why the live tool spindles have the same sensors, though.

The sensor is referred to as SQ390, if that helps in your search. I ended up buying a replacement from AutomationDirect instead of the OEM Balluff sensor, so if you end up needing one, I can give you the part # of what I used.
 
I didn't look at the sensor light while the spindle was rotating. I think you're right that it would be too hard to notice it flashing so quickly. I just moved the spindle slowly by hand while watching for the light to go off and come on as I moved past the notches.

It could have something to do with the phase synchronization. I'm going to see if it moved once I get it running again. The part I'm making has a slot on each end that need to be 90 degrees apart, so it will be easy to find out if the phases moved at all. That doesn't explain why the live tool spindles have the same sensors, though.

The sensor is referred to as SQ390, if that helps in your search. I ended up buying a replacement from AutomationDirect instead of the OEM Balluff sensor, so if you end up needing one, I can give you the part # of what I used.

Hi wmpy, thanks for all the helpful tidbits. The plot thickens. I've got to dig into the live tool sensors. Don't recall seeing those other then I'm sure the live tool motor has one, as it's a normal Servo motor. The need there, at least on my machine, is that all the Rigid Tapping is done with the live tools and spindles locked. Meaning the live tool rotation has to be clocked. I haven't been able to find a working Rigid Tap sequence using a stationary tool and live spindle.

I always look for direct replacements of electro-mechanical stuff searching the OEM numbers. Mori is generally a last resort. With the www at your fingertips it's not that hard. If you're in a big hurry Mori will have it, otherwise I'm willing to work a little for an alternative. Your alternate part number would be most appreciated. :-) I hope your repair works.
 








 
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