... with speed sensor and realizes constant WOB auto-bit-feeding and zero speed suspension function. WOB is smooth and even and bit ... traveling block makes drillers operation easy.5. Field-bus control system forms a communication network founded on PROFIBUS-DP. The ... machine ,oil rig,oil equipment, rig equipment, tiger rig,low-temperature rig, land rig ,truck-mounted rig,mobile drilling rigrotary drilling ...