The present invention relates to an industrial robot system comprising a movable platform (1), an industrial robot (2) located on the movable platform, a sensor system comprising two sensors (4, 5) arranged to detect motions of an object within at least one safety zone (A, B) defined in relation to the sensors, and a safety control unit (7) configured to adjust the speed of the robot if a moving object is detected in the at least one safety zone. Each of the sensors is configured to detect motions within an angle of at least 90° in a horizontal plane. Each of the sensors (4, 5) are arranged so that their positions are adjustable in relation to the movable platform between a first position on or in close vicinity of the movable platform, and a second position located at a distance of a least 0.5 m from the movable platform (1).