Fadal amplifier issue - I'm stumped!

New to me fadal vmc15, has t818e transformer running on 480v. Machine turns on fine, spindle winds up and runs great, control works, estop works, etc. The issue I am having is whenever I enter jog mode I get a servo amplifier fault (error #18) on the axis that is selected. This alarm moves with whatever axis is currently selected to jog. I can continue to reset the alarm and eventually It will allow me to jog the axis for a random amount of before I get the alarm again. In between these servo amplifier fault alarms I have had a motor overload error (cant remember error #) a few times on the axis that is selected, however when I got this alarm I did not get the Amplifier alarm with it, just the motor overload alarm. I have checked my +12v, -12v and 5v and all were right on the money. There is no binding on any of the axis, I can turn them by hand smooth as butter. I have been able to cold start the machine in between these issues, I also was able to make the machine "runaway" by disconnecting 2 of the servo amps. Im completely stumped, my electrician is completely stumped, and Ive searched the forums up and down trying to figure this out but still no luck. Any help would be greatly appreciated and will probably keep me out of the asylum

Ewindward said:

New to me fadal vmc15, has t818e transformer running on 480v. Machine turns on fine, spindle winds up and runs great, control works, estop works, etc. The issue I am having is whenever I enter jog mode I get a servo amplifier fault (error #18) on the axis that is selected. This alarm moves with whatever axis is currently selected to jog. I can continue to reset the alarm and eventually It will allow me to jog the axis for a random amount of before I get the alarm again. In between these servo amplifier fault alarms I have had a motor overload error (cant remember error #) a few times on the axis that is selected, however when I got this alarm I did not get the Amplifier alarm with it, just the motor overload alarm. I have checked my +12v, -12v and 5v and all were right on the money. There is no binding on any of the axis, I can turn them by hand smooth as butter. I have been able to cold start the machine in between these issues, I also was able to make the machine "runaway" by disconnecting 2 of the servo amps. Im completely stumped, my electrician is completely stumped, and Ive searched the forums up and down trying to figure this out but still no luck. Any help would be greatly appreciated and will probably keep me out of the asylum

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do you have the right transformer settings in the back of the machine for your correct voltage coming into the machine?

are you running commercial 3 phase or you using a converter?

im running commercial 3 phase. All voltages coming out of the transformer are right on, I believe the legs were 237, 238, 239v

Ewindward said:

im running commercial 3 phase. All voltages coming out of the transformer are right on, I believe the legs were 237, 238, 239v

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Yes but what is the AC voltage to the servo amps? Sounds under powered.

Ziggy2 said:

Yes but what is the AC voltage to the servo amps? Sounds under powered.

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Im going off of memory since im not at the shop right now but I think I had 118v to the amps

So I must admit im terrible with this stuff. Disregard my last response because I'm sure that is incorrect. My electrician checked voltages according to the manual troubleshooting guide and schematics and all seemed good according to him. I am not very electrically savvy, which makes this much more difficult for me. I'm going to put a call into fadalcnc tomorrow afternoon to see if they have any ideas or maybe get a service tech in to take a look. If anyone has anything I can try in the meantime it would be greatly appreciated. I have tried unplugging and reseating the cards with no luck. I have also tried resetting all of the relays I was able to find. God this thing is driving me crazy, and now I have work I cant get done

Ewindward said:

So I must admit im terrible with this stuff. Disregard my last response because I'm sure that is incorrect. My electrician checked voltages according to the manual troubleshooting guide and schematics and all seemed good according to him. I am not very electrically savvy, which makes this much more difficult for me. I'm going to put a call into fadalcnc tomorrow afternoon to see if they have any ideas or maybe get a service tech in to take a look. If anyone has anything I can try in the meantime it would be greatly appreciated. I have tried unplugging and reseating the cards with no luck. I have also tried resetting all of the relays I was able to find. God this thing is driving me crazy, and now I have work I cant get done

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Assuming your machine was running fine before you moved it into your shop, then the issue should be rather simple.

If all 3 axis are doing this at the same time, that implies that the issue must lie in something that is common to all 3 axis.

If a servo amplifier is fed to low of a voltage, the servo motor will have a difficult time positioning rapidly enough to not cause positioning errors.

If a servo amplifier is fed to low a voltage it will also increase to current to the servo motor to compensate for the lagging position error. This tends to cause over current conditions since the amplifier is tacking motor current.

This leads to the another question. How good at controls is your electrician? There are electricians that are really good at pulling wire and installing conduit and then there are the controls type electricians that have their heads into what the symptoms indicate. Two different skill sets and both are electricians.

Not saying your guy doesn't know what he is doing but this problem should not be hard to fix.

The only other issue could be that someone modified the servo axis parameters. they would have to do all three the same to get the same behavior on all three axis. This is not likely unless someone did not want the machine to work for some reason. Not likely.

My electrician is pretty good, built machines for cincinati-milacron back in the day as well as a few other robotics companies. I think he knows his stuff, but he's been out of that kind of work since the 90s, so who knows. He had said it could possibly be an issue with the power supply (ac ripple or something), and since it seems to be original it might be worthwhile to replace it since its cheap and they're known to crap out causing weird issues. Any thoughts on that? He's family and im not paying him anything for his help so I feel pretty bad about having him come by the shop constantly.

The computer side of your controls is likely ok. The cheap power supply you are referring to is for the computer side.

I would be looking at the power supply voltage at the servo amplifiers such as looking for a blown fuse on a leg that feeds the power transformer for the servo amplifiers.

You said the power into the machine was okay. The machine use to run. The table axis move easily. You have following errors and servo motor over current errors on all three axis.

What is the one thing that is common to all three axis and not part of the control computer side? The power feeding the servo amplifiers. Now you also could have an issue with the high voltage DC power supply on the servo amplifier.

Also remember that just because a fuse reads okay does not mean it will necessarily conduct power under load. More than once I have seen fuses that check okay on resistance but open under load.

Thank you so much for your help. I will take a look at the fuses this afternoon and see if that could be the cause of my woes

I second the idea that the voltage at the servo amp is the problem WHEN UNDER LOAD! If you have a bit of resistance on any voltage lead into the machine, it may read fine with no current through that leg. But Ohm's Law tells us that there will be a voltage drop across any resistance which is equal to the current through it times the resistance. For example, suppose you have a bad crimp which has a 1 ohm resistance. When you push 30 amps through it, that will mean 30 volts (1 ohm times 30 amps) will drop across the bad crimp connection. THat may be enough to trigger a fault. I do not know what sorts of transient loads your machine draws in a sudden move situation, but the basic principle applies.

One way to troubleshoot this is to use a portable oscilloscope with the right sort of probes to with stand the voltages involved which can trigger on a voltage drop, or otherwise record the time behavior of the voltages going to the inputs of the servo amps. Your electrician may have such a tool. There are other methods. The drop may be both sudden and also very short, as the fault condition may shut off the load (servo motor amp) quickly. Just looking at the voltage with a hand held voltmeter probably will not catch the transient.

It may also be something else, but after a lifetime of being beat to death by my assumptions, one rule I always follow is: "Never assume the power supply is supplying power!!!". So consider the voltages both with low load, and with full rated current being drawn. There will always be some ohmic drop in the wires due to their finite conductivity, but circuit breakers, fuses (as mentioned), bolted connections, crimped connectors, etc can have enough resistance to really drop the voltage to the load when significant current is being drawn. Before assuming bad boards or parameters, etc, be SURE that power to the inputs of amplifiers, and other critical items is absolutely fine at all input current draw. This is something tangible and relatively inexpensive that you can systematically do. My bet is that that will find the issue.

Best wishes!!
Michael

My 2 cents. I don't care where your electrician worked, they are good for pulling wires,
and only when absolutely needed getting permits and talking to the electric company.

Unless they are a real techno wonk, I wouldn't want them messing around in my machine.

2 things.. first.. The trouble shooting guide in the manuals is really handy.. Notice that
before it even asks you what the problem is, it wants you to check voltages and AC ripple.

2nd thing.. If you are experiencing odd ball errors. 95% chance that it is the power supply.

The "stock" power supply is nothing more than a WAY overpriced POS PC power supply. They suck.


Here is how I troubleshoot errors on a Fadal. Are there different errors randomly? Its the
Power Supply.. 99.9% of the time.. I've wasted more time dicking around trying to find a
problem, when its the damn power supply... Even when they check ±12 and 5v perfect, some of them
WILL NOT run the machine..

The new power supply they are selling. It fricken awesome, it cures a lot of ills. Pain in the ass
to get it in there the first time, but completely worth it. Even if the machine and boards are old
and has some leaking caps that a PC power supply can't keep up with, the new power supply they have
will keep up..

Don't even waste your time trying to diagnose anything. New Power Supply, you will need it eventually
anyways. Just do it now and save yourself a lot of time.

Also, I would tap another 10V higher. 240V is the "Death Point" of spindle drives(guess how I know that?)
and you are right at the top.. They run fine 220 to 240.. All it takes is a little wiggle in your
line voltage and you are over. You gain nothing by running at 239.. Tap her higher and bring her
down to 230ish. My machines are tapped for 250 to bring my leg to leg down to about 232-234.

And if you are a bit timid about checking this type of stuff, which I'm guessing you are... Its easy,
you just have to get in the right mind set.. You aren't dealing with a big giant machine with all kinds
of electrical and mechanical systems. You are simply dealing with a one tiny little system, that happens
to be attached to a big giant thing.. You don't have to know how to rebuild an automatic transmission
to be able to replace a cigarette lighter in Bugatti, you just need to know red to black is supposed to
be 12V. Super simple, and they don't get much easier than a Fadal.

Bobw you are correct when you say I seem to be a bit timid about working on these things. Im really young and invested a lot of money (for me) into the couple machines I have, and the thought of destroying it (or myself) scares the crapola out of me and could easily put me out of buisness. I plan to learn more about these once my situation/buisness isn't so cutthroat and vulnerable, and its usually much cheaper and faster for me just to hand over my wallet and first born child to the repair guy so I can get back up and running asap. I actually ordered a power supply already, I guess we will see how that works out, and I will definitely take your advice on the taps. Worst case Ontario, I pay the guy in the van.