measuring, controlling, and regulating instruments, systems, and apparatus; namely, data loggers, analog and digital computers, recorders, indicators, integrators, regulators and controllers of combustion, of processes and of fluid flow and conditions pertinent to fluids such as rate of flow, level, temperature, and pressure; remote recording, indicating, integrating, controlling and telemetering instruments, adjustable orifices and other apparatus appurtenant to such instruments; gas analyzers, instrument and control panel boards, time cycle instruments and controllers, weighing scales, and electric and fluid pressure selector switches; pressure, temperature, level and fluid flow responsive control valves; and charts peculiar to the operation of said instruments and apparatus; process control instrumentation; namely, operator interface units; namely, digital controllers, configuration and tuning modules, operator consoles; process control units; namely, controller modules, logic master modules, digital slave modules, analog slave modules, analog master modules, analog output modules, controller interface modules; termination units for computer interface and process input and output wiring; and power modules for both modulating and sequential control, data acquisition, operator interface, and computer interface for industrial and utility applications; stand alone controllers, communications interfaces, smart transmitters or monitors and configuration engineering modules; liquid analysis equipment for monitoring pH, conductivity, specific ion and oxidation reduction potential; and flame scanners