Recently, I was given a training task on the design of automatic control systems, using instruments. Implementation using analog instruments and PLCs; no experience
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Recently, I was given a training task aimed at college students majoring in electrical engineering and automation. I haven’t been in contact with it for many years. How are instrument control system designs carried out these days? For the design of automatic control systems, are there any ready-made solutions that use analog instruments and PLCs? I have no experience in this area; please offer some guidance. Specific requirements: 1. Flow control system 2. Temperature control system. The design shall be developed based on the control of a single object. It would be best to have sample essays for reference. I’ve looked for many people, but truly there’s no one to turn to. I earnestly ask everyone for their help. There is a pretty good book on this topic. The general structure is as follows: Table of Contents: Project Description; I. Description of the process flow; II. Project requirements. Task 1: Project analysis – I. Analysis of control tasks; II. Introduction to typical equipment; III. Analysis of safety factors. Practical training: Visit to an industrial production facility. *Question 1. Task 2: Determination of the control scheme – I. Scheme for measuring and displaying methanol flow rates; II. Control of methanol flow rate and air flow rate; III. Scheme for controlling the ratio of water vapor to the binary mixture; IV. Control scheme for the material system involved in the oxidation of methanol to formaldehyde. Practical training: Setting of ratio coefficients. *Question 2. Task 3: Selection of flow measurement devices – I. Basic knowledge of flow measurement instruments; II. Differential pressure flow meters; III. Rotameters; IV. Electromagnetic flow meters; V. Other types of flow meters; VI. Selection of measurement devices for this project. Practical training: Calibration of rotameters. *Question 3. Task 4: Selection of control devices – I. Selection of accumulators; II. Selection of calculators; III. Selection of controllers; IV. Selection of actuators. Practical training: Adjustment of valve setpoints. *Question 4. Task 5: Installation and commissioning of the control system – I. System wiring diagrams; II. Equipment installation; III. Preparation and debugging; IV. Commissioning; V. System maintenance; VI. Defects in the project control scheme and ways to improve them. Practical training: Flow control system using single-loop ratio control. *Question 5. References. Source: Flow Control Systems – Part 3 of the Textbooks for Project-Based Teaching in Automatic Control (Textbook for secondary vocational education), author: Cai Xizhong
Design of automatic control systems: who has ready-made solutions using analog instruments and PLCs? I have no experience in this area, so please offer some guidance. Specific requirements: 1. Flow control system 2. Temperature control system. It should be a very simple task. Here’s some guidance: 1. Select the appropriate measurement and control solutions; for example, in the case of flow control, it is necessary to choose a method for measuring flow. This requires taking into account the relevant process conditions such as the medium, pipes, flow parameters, and allowable pressure losses. There is a wealth of information available on flow measurement methods and the selection of appropriate instruments in the “Field Instrumentation Technology Exchange Area”. As a supplementary point, when selecting instruments, pay attention to whether explosion protection is required. 2. Control scheme: Whether flow or temperature control employs a single-loop system or other complex control schemes can illustrate the characteristics of the control. 3. If conventional instruments are chosen, secondary instruments and gauge panel design are added after the selection is made; if a PLC is used, programming is also required to meet the relevant requirements using ladder diagrams or other algorithms. 4. Other things, of course, there are many more. 4. Finally, one thing to note when selecting instruments is to check whether explosion protection is required.
For example, in the control of a distillation tower, there is the flow rate of the feed material and the steam flow rate used for heating. The main medium for distillation. Measurement methods, specific parameters of steam, pressure, temperature. Nothing is clear. There are also specific parameters for the tower top pressure, along with specific design requirements. It’s the preliminary design.