Homework-04 Solution (100 marks) Read Chapter_4_Time_Based_Measurements.pdf Question 1 (10 marks) When converting an analogue value to a frequency, consider the following diagram describing the system. The frequency changes from 20 MHz to 18 MHz and the system samples at an interval of 2ms. How many counts does the microprocessor detect at, a) 20 MHz? b) 18 MHz? What is the difference in terms of number of counts detected by the microprocessor? Solution: 1 1 a) Converse 20 MHz to time length: T 0.00005ms f 20,000,000 2ms Number of counts in 2ms: N 40,000 0.00005ms 1 1 b) Converse 18 MHz to time length: T 0.000055556ms ...
Read Chapter_5_Output_Control_Methods.pdf Question 1 (10 marks) Draw a PID control scheme and write down an equation to describe the PID control. Compare the differences between the “bang-bang“ control and proportional control. What are the functions of Integral and Derivative terms in the PID equation. Solution: Draw a PID control system: (Figure 5.5, page 111) Write down an equation to describe the PID control: (page 111) Compare the differences and the advantages between the “bang-bang“ control and Proportional control: (page 105) “Bang-Bang“ control or ON-OFF control is the simplest control system. It turns ON when the system needs more INPUT and tuns OFF if the system doesn’t need INPUT any more. The INPUT is similar to the PWM square wave (running ON and OFF during the length of the needed INPUT). Bang-Bang control is similar to the PWM input signal Proportional control: Bang-Bang con...