US Patent 7665533 Electronic threading control apparatus and method

A system to control a threading operation includes a first tubular and a second tubular, wherein the first tubular and the second tubular include corresponding thread profiles. The system further includes a drive assembly configured to rotate the second tubular with respect to the first tubular, wherein vertical and rotation movements of the drive assembly are controllable through a drive assembly controller, and wherein the drive assembly controller is configured to operate in a threading mode when the second tubular is threaded with the first tubular.