Mitsubishi M70 controller and turret referance point alligment

Dear friends,

We have got following problem. Our operator plugged of cable of encoder from amplifier of turret. then he plugged it back. but when we turned on machine we got turret alarm and turret revolving alarms.(alarm number 1056) somebody knows how to make turret referance point again? unfortunately we have no parameter book of this machine. I need instruction how can I make referance point again. First I opened maintenance from PLC SW. then I changed parameter 6412 bit0 to 1 and unclampped turret. later made adjusment of turret. but now when I change 6412 bit0 to 0 and close PLC SW turret doesn't clamp. what should I do?