Problem- Fanuc OT, 520 alram will not reset!

[Darens]

I have a Kingston CL-25B Lathe 1996. The other day I had a crash. The turret slammed into the chuck. Now I have a 520 Alarm. +Z hardware over travel. I have looked through the threads and tried the limit switches, moved the screw by hand to stops, set 700,701, and 65 parameters(at different times) and pressed P and CAN, and pressed P Q and Can. Still will not reset. Can someone please help!
Thanks for now,
Darren Ens

[Al_The_Man]

Have you looked at the diagnostic screen for the +Z limit?
Push on it while watching the screen it should change from 1 to 0.
If the switch is OK, I would guess you have opened up the switch conductors somewhere, these limits are active low, they are normally closed so open the switch or break the conductor and you have an over travel.
The diagnostics screen and the Ladder, if you have it, are your two best friends.
Al.

[Darens]

I can't see a +Z limit in diagnostics. But Y No. 0048 bit 4 is flashing 0 to1 to0,etc.
Noticed now too after manually moving screw to the limit switches, that now when I strart the machine both -Z and +Z alarms are on, and I can'tt get either one off. But when I start the machine while holding P CAN, then the -Z cancels, but not the +Z????

[Al_The_Man]

P cancel is a software limit cancel, what you have sounds like a hardware limit problem.
If you cannot get the Z+ diagnostic bit to change when moving the limit, then this is your problem.
If Z+ and Z- over travel is on, then it is uaully the 24v+ to the switches that is open.
Al.

[Darens]

Not sure if it helps, but on the back in the control panel, there is a panel of relay switches, and the second from the top and second down is clicking on and off.

[Al_The_Man]

Hopefully you have the OEM schematics? This should tell you which relays are activating if they are label'd or identified.
Al.

[GPena]

Al is right, the hardware limit travel is active.

I think that when the machine crashed the axis lever touched it, maybe it has dirt, oil or something to get stucked and didn't release when you moved the axis. I suggest you to manually activate it several times to release it from the active state.

To see what is the diagnostic related to this microswitch you can press it ans release it several times and a diagnostic (bit) between 0 and 20 must change. Of course there must be another person at the nc screen.

Good luck.

[fanucman]

Originally Posted by GPena Al is right, the hardware limit travel is active. \

Check the limit switch for Z axis.. you should have a schematic.. locate the switch and replace/ fix it...

[Darens]

Thanks for all the input guys. Found out that I broke the plate holing the screw in place right by the switch. When I remove the switch completely, but still wired in, the machine works fine. So I think the switch is shot too. Ordered one yesterday. Find out soon.

Thanks again.