Something about self-control* * question

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1. What is closed-loop control? answer: A closed-loop control system is a system that controls based on the deviation between the controlled variable and the given value. 2. In closed-loop control, what parameters are commonly used to measure control quality? answer: When analyzing the performance of a closed-loop control system, rise time and transition time are often used to measure the rapidity of the system, overshoot and attenuation represent the stability of the system, and static error represents the accuracy of the system. 3. What is sequence control? answer: According to the requirements of the production process, regular control of the switching volume is called sequence control. 4. What is the function of the transmitter? answer: The function of the transmitter is to convert the controlled quantity measured by the measuring element into the signal type required by the controller. 5. What are the advantages of the proportional regulator? answer: The advantage of the proportional regulator is that the response speed is fast and the adjustment effect can be effective immediately. That is, when a deviation signal is input, the output of the regulator immediately changes in proportion to the deviation, which can quickly overcome the fluctuation of the adjusted parameter caused by interference. The larger the output deviation signal, the stronger the output adjustment effect, which is a significant feature of the proportional regulator. 6. In electric PID regulation, what is the role of the deviation detection circuit? answer: The function of the deviation detection circuit is to compare the input signal with the given signal, and send the compared deviation signal to the input end of the modulation amplifier. 7. Briefly describe the transition process of the PID adjustment system. answer: When interference occurs, the differential adjustment takes immediate action. At the same time, the proportional adjustment also plays a role in overcoming the deviation, reducing the amplitude of the deviation. Then the integral begins to take effect. This system has a stronger ability to overcome the deviation than the proportional-integral system. After the PID adjustment write only undergoes a short attenuation and oscillation, the deviation is eliminated and enters a new stable state. 8. Briefly describe the signal source of the three-impulse water supply regulating system.: In the three-impulse water supply regulation system, the regulator accepts three input signals: The main signal drum water level H, the feedforward signal steam flow rate D, and the feedback signal feed water flow rate W. Among them, steam flow and feed water flow are the main reasons for changes in the drum water level. When a disturbance causing a change in the drum water level occurs, the regulating system takes immediate action and can effectively control changes in water level. 9. What are the general principles for selecting regulators for stage control systems? answer: (1) The secondary loop should surround the place where the strong disturbance is introduced. (2) The secondary loop should surround the object with a large time constant as much as possible. (3) The main and auxiliary regulators should choose regulators with different adjustment rules. 10. Why can’t differential adjustment be used alone? answer: The output of a simple differential regulator can only reflect the speed of the deviation signal, but cannot reflect the size of the deviation. The adjustment result cannot eliminate the static error. Therefore, the differential regulator cannot be used alone, but must be used in combination with proportional or integral laws. 11. What control method is used for water supply control in our factory? answer: Cascade three-impulse control 12. In water supply control, which is the main signal, which is the auxiliary signal, and which one should be connected in reverse? answer: The drum liquid level is the main signal, the feed water flow and the steam flow are the secondary signals, and the steam flow should be connected in reverse. 13. What is negative feedback? answer: It means that the feedback signal sent back from the output end is in opposite phase with the input signal, and the signals cancel each other out, weakening the input signal. 14. In an automatic system, what conditions should be met to achieve disturbance-free switching? answer: The output of the regulator is equal to the given.