i am able to run the m/c with out encoder by setting bits in parameter 4000.0,4001.1,4005.0 from 1 to 0. But eventhough i do this the axisnot responding to G00 and G01 commands. Also i saw a m/c without encoder by bypassing the bits. Thats why i am asking this. Pls tell me if u know that. Also tell me the M codes and descriptions about it for Fanuc 21-TB.