Systems and methodologies feed for testing drilling control systems

An apparatus for testing an integrated control system (1) in which the integrated control system (1) is adapted forregulering of a drilling vessel (2), wherein the drilling vessel (2) is adapted for drilling operations, wherein the integrated control system (1) comprising * a drilling control system DCS (3) for controlling a drilling system (7) *, where the drilling control system (3) is arranged to receive sensor signals (31) relating to the drilling operations and further to supply control signals (33) to the drilling system (7) to perform the desired drilling operations, * wherein the drilling control system (3) is arranged to control one or more drilling operations and includes one or control subsystems, * the apparatus is adapted for testing the error in the integrated control system (1) due to failure of one or more control subsystems of the integrated control system (1 ) or from the failure of the interaction between control subsystems of the integrated control system (1) or from a combination thereof.