Quick ! Ships tomorrow ! Fanuc 20M control problem !

How do you get an overtravel alarm to reset when it's not overtraveled anymore ??

Sheesh, like new Miyano drill/tap center ran perfect every time I tested it, so today, the day before shipping it to customer I run it once more thru a program just to take a video of it for proof it ran properly before shipment.

Everything perfect as per previous runs, goes thru a program twice. Then just for the heck of it I rotate the tool carosel in manual mode, somehow the Z overtravels, I get alarm 500, Z+ overtravel. I hit the overtravel release button, nothing happens, Z servo still disabled.

Eventually I turn the Z ballscrew by hand and get it completely off limit switches, and it *still* refuses to get out of Z+ overtravel alarm mode. Hit control reset, have cut power at main for complete reboot many times, Z limit switches are like new, clean and not stuck, voltages at various internal power supplies on the money. Curiously I can get Z to go down if I remove a proximity switch on Z, but can't get it to go up...kinda moot anyway as even if it did go up the damn alarm would still be on.

Backup batteries good, parameters seem to be all there. I even temporarily altered Z overtravel parameters to match X and Y to see if that made any difference...nothing.

Soooo, got this cringer situation where I don't know whether to call off the trucker and pay a few hundred for his trouble or hope a solution comes by 11:00 AM tomorrow. Any ideas ?

try
cancel p

I don't have the manual for the 20M but Fanuc generally have several parameters regarding stroke limits etc, there is a parameter for ignoring the stroke limit until home is performed (5200 on a 15)
also by moving the tool turret manually may have affected something in the tool change routine, there are 3 sets of software limits #1 is usually the basic machine soft OT and there are #2 #3 which can be turned on and off by G code. If you have the manuals I would look at that possibility.
Look at the specifics of the alarm as each OT wether hard or soft has a different alarm#
M.

Yeah - on the Fanuc - hold down cancel and P buttons and keep them held down as you boot the control.

Think Snow Eh!
Ox

pi and Ox, the P /cancel trick did clear the overtravel error, but damned if I still wasn't having problems homing the Z. It would go up almost all the way, but not quite, and then trip yet another error.

Finally figured out a proximity switch was tripping a few thou before the home limit switch tripped. Apparently it should have been the other way around and this is what was confusing the Miyano's little Fanuc brain to cause the original error. So, lowered the proximity bar a tad and all is right with the world, machine back changing tools and running program after program perfectly !

Hey thomas

You forgot to say...

"thanks god for this forum and the extremely knowledgable and helpfull (and good looking) people in it..."

How could you forget that part ?

Solar, I have said that before in reference to other problem solving here, but in this particular case the actual saving grace was the tech at Miyano when I called this morning. First thing out of his mouth was "hit P and cancel", which as I mentioned did get rid of the overtravel error such that I could attempt 'home', but more problems followed, as 'home' was not to be. Even clicking my ruby red slippers and repeating "there's no place like home" had no result. It was the troubleshooting tips from "Miyano Man" that came after that, that really led to the final solution

As is often the case with troubleshooting over the phone, even the tech didn't think of the real source of the problem..in this case the proxmity switch being out of adjustment, but the tips he gave were invaluable in leading me to that discovery.

So was this the same prox switch that you were monkeying with ?

Even clicking my ruby red slippers and repeating "there's no place like home" had no result.

OH MY!

Where's that "This thread is worthless w/o pics" GIF?



(Just don't boot it up with delete/P held down. )

Think Snow Eh!
Ox