tailieunhanh - Ebook Programmable controllers theory and implementation (2nd edition): Part 2

(BQ) Part 2 book "Programmable controllers theory and implementation" has contents: System programming and implementation, PLC system documentation, data measurements and transducers, process responses and transfer functions, process controllers and loop tuning,.and other contents. | C HAPTER E LEVEN SYSTEM PROGRAMMING AND I MPLEMENTATION He that invents a machine augments the power of man and the well-being of mankind. —Henry Ward Beecher Industrial Text & Video Company 1-800-752-8398 SECTION 3 System Programming and Implementation PLC Programming CHAPTER 11 C HAPTER The implementation of a control program requires complex organizational H IGHLIGHTS and analytical skills, which change depending on the application. Because they are so varied, we cannot explain how to solve every specific control task. Nevertheless, we can provide you with techniques and guidelines for completing this problem-solving process. In this chapter, we will introduce a strategy for implementing a control program, which includes program organization, system configuration, and I/O programming. These strategies also apply to PLCs with the IEC 1131-3 programming standard. Additionally, we will present both simple and complex PLC programming examples. After you finish this chapter, you will be ready to learn how to document the PLC system—the last step in implementing the control program. 11-1 C ONTROL T ASK D EFINITION A user should begin the problem-solving process by defining the control task, that is, determining what needs to be done. This information provides the foundation for the control program. To help minimize errors, the control task should be defined by those who are familiar with the operation of the machine or process. Proper definition of the task is directly related to the success of the control program. Control task definition occurs at many levels. All of the departments involved must work together to determine what inputs are required, so that everyone understands the purpose and scope of the project. For example, if a project involves the automation of a manufacturing plant in which materials will be retrieved from the warehouse and sent to the automatic packaging area, personnel from both the warehouse and packaging .