9 Computer software and computer hardware; computer based information and control systems comprising differential pressure transmitters, level transmitters, temperature transmitters, vortex meters, magnetic meters, coriolis mass flow meters, controllers and recorders for sensing, measuring and managing industrial process variables such as temperature, pressure, liquid level, flow and composition of materials; computer peripherals, industrial control computers, industrial controllers, programming workstations, operator consoles, computer programs for use in the field of industrial control, and computer systems comprising the same; solenoid valves; sensors; instruments and apparatus for measuring pressure (using pressure sensitive and semiconductor sensors) and fluid density; apparatus and analytical instruments for measuring, indicating and recording chemical properties, pH and conductive properties of solutions