Abstract: A cursor control system is provided whereby a discrete-direction input device, such as a joystick, may be used to accurately move a cursor in both straight and curved lines. The cursor control system may be implemented in software and is ideal for with an electronic drawing application having only a rudimentary joystick-like control and various user buttons. A cursor capable of indicating the direction of movement, such as an arrow, is provided and may be aimed with the joystick. During drawing or movement, depression of the joystick causes the arrow to rotate towards the selected direction at a fixed angular rate such that the arrow travels in a smooth arc. The control system may be arranged so that the rotation of the arrow stops when it has reached the selected direction or so that the arrow continues to rotate even after it has reached the selected direction. The former control method may be used for moving and the latter control method for drawing.

Abstract: A transmitter for use in a process control system has externally accessible actuators for permitting external adjustment of the zero and span (or full scale) settings of the transmitter. The transmitter has an explosion-proof housing which includes an interior chamber in which transmitter circuitry is located. Each of the actuators includes a movable magnet which operates a magnetic reed switch located within the interior chamber of the housing through a wall of the housing. Each of the magnets is mounted on a movable actuator which extends into a blind hole in a wall of the housing. By moving the magnet within its hole, the corresponding reed switch can be changed from a non-actuated to an actuated state. When the zero reed switch is actuated, the transmitter circuitry adjusts its output so that the present value of the parameter represents a process zero.