[Greenbuggy]

Trying to learn myself about this old control, of course that naturally means screwing things up and trying to figure out how to undo the screw up.

Machine is a ~1984-85 Okuma Millac MC-4VA with a Fanuc 6M-B control

Was trying to get machine to home all axis and I went too far on X and hit the hard limit, the hard limit must be part of the E-stop circuit because when it tapped that limit switch my "machine ready" light immediately shut off as if I'd hit the E-stop. If I hold the "machine ready" button that normally turns all the subsystems (servo amps, lube pump, hydraulics, spindle drive) the light comes on but "servo error 401" shows up on the alarm screen. With error 401 up, the servo amps will not reset (and hitting the "reset" button causes the alarm to disappear for a couple seconds then immediately reappear) as such I can't jog the table in the opposite direction so that it gets off the hard limit switch.

Some googling suggests restarting the control while holding P+cancel buttons down which didn't appear to do anything. I have to wonder if the hard limit switches are somehow tied into the servo amps, unfortunately this machine didn't come with wiring diagrams to tell me if or how.

Is there an easier way to do this than unbolting and disconnecting the axis servo motor and rotating it until its off the limit switch? Or disconnecting the hard limit long enough to jog it back to center? I can do either if necessary but it seems like more work than it ought to be. Elsewhere I've been advised to just move the screws with servos off which works fine for X/Y but not Z, as Z has a servo brake and will not move unless power is applied to loosen it.

Wondering also what my options are to drip feed programs to this machine, how much do I have to spend to make it do what I want?

Last question, is there a procedure or call to make the machine automatically home itself? I'm a fanuc n00b all my CNC experience has been with a LinuxCNC retrofitted machine.

[agering]

You need to set the parameters of the stroke limit (143~157) for each axis. This procedure is well described in Maintenance manual. Please, tell your e-mail to my private message. I can send it to you.
For Drip Feeding is two ways of the decision this problem:
- Change the Base software to patched (with DNC);
- Install the BTR board to PTR connector.
Please, tell me series/version Base software your Fanuc 6M-B.

[Greenbuggy]

You need to set the parameters of the stroke limit (143~157) for each axis. This procedure is well described in Maintenance manual. Please, tell your e-mail to my private message. I can send it to you.
For Drip Feeding is two ways of the decision this problem:
- Change the Base software to patched (with DNC);
- Install the BTR board to PTR connector.
Please, tell me series/version Base software your Fanuc 6M-B.

Tag on cabinet says "Fanuc LTD Type A02B-0060-B201 Serial 7107991 Date 1984-0" If that isn't sufficient let me know where to find that information elsewhere.

How does one patch the base software (is this an upgrade from Fanuc?) if the base software is upgraded how does the program get from the source computer to the 6M?

I'm assuming "PTR" is the punched tape reader and thats what most of the BTR boards connect in place of?

I'll send my email shortly.

[agering]

For get the series/version of software need to CNC ON under pressed button EMERGECY STOP. The series/version will appear on CRT screen.
I know one chinese version of software patch with DNC for connection to RS232. After I have taken out from it error this version works safely.
BTR PCBs connected to Main Board CAT connector for PTR device. The Other side BTR is connected through RS232 to computer with installed in him DNC application. I use on my own machines BTR and DNC network software of the our development. Information for it here:
IinDoc
Sorry, more in russian...

[spark-el]

P-Cancel on start-up is only to cancel soft limits, for a hard limit there should be an OT Bypass button, if not try holding down the start button while you simultaneously jog. If no success, you may be able to physically pull the axis off the switch, if you can't do that then try to remove the switch or the dog to get out of the situation, then re-home. After that you need to check the home switch, you should never hit hard OT while homing unless that switch is faulty.

[Greenbuggy]

Ok machine says its a 6MB series M51 V12

I was unable to find any sort of bypass button but jumped out the hard limit switch and was able to get it to come off the hard limit that way.

[spark-el]

Good! That's what the OT button does, except it jumps all the axes switches. If you were doing a home move when it OTed, then you need to check the home switch & dog on that axis, should never happen. Be sure to remove cover, see if it's full of water or chips. You can make your own bypass button too if you wish, for future problems like this.