EEC 608 Industrial Control Electronic Exam 2022

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EEC 608: A 3-page Second Semester Examination for Industrial control electronic (EEC608), University of Buea College of Technology, Dept of Electrical and electronic Engineering, instructors Dr. Feudjio Cyrille / Dr. Adelaide Kengnou, Credit 4, 17/06/2022, 3 hours. Exercise 1 (25pts): direct-on-line two-direction one-speed 3-phase motor starting using a Twido PLC -- given power/control diagrams, students give the operating mode, assign push buttons/contactors (S0/S1/S2, K1/K2) to PLC inputs/outputs and draw the ladder diagram, and draw the PLC control wiring diagram for 220V contactor coils. Exercise 2 (20pts): a closed-loop proportional position-control robotic system (motor/robot arm/feedback potentiometer, computer-DAC command path, difference op-amp, proportional gain stage, power amplifier) -- listing/identifying closed-loop elements, the computer-DAC's role and DAC output characteristic, DAC resolution calculation and a binary-weighted D/A converter design, the system's operating mode, the gain-control element, the proportional controller's steady-state-error drawback and a PI-controller remedy, and a PI-controller schematic with transfer function. Exercise 3 (25pts): PID controller tuning via the Ziegler-Nichols second method for G(s)=1/[(s+1)(s+3)(s+5)] -- open/closed-loop transfer functions, the Routh-Hurwitz critical gain Kcr=192, the ultimate period from a given 4.8 rad/s oscillation frequency, PID parameters from the Ziegler-Nichols table, and an op-amp PID controller circuit design.