Fanuc Oi MD Z Axis Stuck

Hello,

I have been working with a Hanland Vertical Machining Centre with a Fanuc Oi MD control. For a few days now it has been stuck on the +Z axis Overtravel, when I try to press the servo release button and the -Z button, nothing happens ( does not move even a mm).

When I reduced the Z feedrate in the parameters and tried pressing the servo release button together with +Z button the axis moves. that is the problem it moves in all other direction expect the -Z direction.

I have now run out of ideas on what could be wrong coz initially I thought it was the z axis motor which had a problem but now since it can move up and not down I don't understand what the problem is.

Kindly help me in this?

It sounds like the limit switch wires are reversed? It should only allow movement away from the switch it is on. Worse case pull the wire from the switch and move off slowly.

Probably need to cancel softlimits on power up. Not sure on the oi, but it used to be hold the cancel and p button during power up.

Thanks guys for the advice. But both options have not worked so far.

I even removed the limit switches physically and switched them manually but even when I activate the - Z limit switch, it shows a - Z over travel alarm and I am able to move it slowly in the +Z direction but not in - Z direction.
When the limited switches are removed all errors disapear but the machine cannot still move in the - Z direction but it can move in all other directions..

I have even tried the P+ can but no change yet.

I am still troubleshooting it but would appreciate your assistance..

Some machines need to be in either MDI or manual mode to be able to release over travel.

If the switches are changing the right bits, then under the tire is on the right track. It is likely the soft limits. Find the stored stroke parameter and open it up, just be sure to put it back when done.