Controllers with analogue signals for use in industrial-process control systems. Methods of evaluating the performance|Control signals, Flow measurement, Electric control equipment, Automatic control systems, Circuits, Pneumatic control equipment, Controllers, Instrument scales, Performance testing, Air, Test equipment, Accelerated testing, Verification, Test atmospheres, Process control, Environmental testing, Control equipment, Analogue signals, Industrial, Frequency response, Drop tests, Noise (spurious signals), Control systems, Electrical testing, Testing conditions, Calibration, Electric power system disturbances