Components of Fatigue Test Controller

This paper describes about the development of computer controlled single channel controller used in servo hydraulic test system for fatigue testing of materials. The closed loop control obtained with load cell and LVDT which provides an electrical signal to the controller proportional to the mechanical position of the actuator or load exerted by it. The electrical signal is passed through signal conditioning circuitry for amplification of the signal which is fed to the servo-controller to generate an error signal. The feedback mode whether in stroke (LVDT) or Load mode is compared with respective set points using a differential amplifier. Add -on boards of digital to analog converter is used to convert the set-points which are in digital form to analog value. The operations of the controller are displayed on the console of the computer.