Fanuc 0i-mc tool crash

[motordude]

Hello all,
I was setting the tool length and before doing so I wrote this line (as usual): G30G91Z0.
Normally the machine returns to zero, but not this time, it went in opposite direction into the table.

How is this possible? What did I do wrong?

Best regards
John

[underthetire]

Seen it before, but with a G28 (first zero return). Every time the G91 was omitted. I know there are a few on here that says you don't need the G91, but all the Fanucs i've set up need it. We had an apps guy do that once, brand new machine, never even cut a part. Bounced the Horizontal spindle off the pallet. 50K damage to the machine. Full rapid 2400 IPM.

[jvangelder]

If im doing a refrence return though code ive always used G0G49Z0.

However on an OI-MC you shouldnt have to clear the current height offset to set a new TLO, just jogg the tool to place, then on your desired tool offset punch Z, then hit the input C soft key