TABLE OF CONTENTS Before selecting an automation system, business goal are translated to systems strategy by doing analysis. The requirements identified during the analysis are part of the automation plan. Automation plan is developed to implement the systems strategy. The automation plan outlines the control system architecture including hardware, operating system and application software, database system and communications.
For selecting system architecture, two options are there:
Complete solution provided by the vendor, where the vendor chosen provides complete solution for process automation and integrates it with the business system.
User-developed solution, wherein the user selects the components of system architecture at enterprise level to ensure consistency, compatibility and supportability. The choice of technology is made and standards are set, and any application adhering to the standards can be used. This approach ensures better integration with other systems and allows selection of technologies that fulfill the business needs of the enterprise.
The PLCs were initially developed and used for discrete operations as a replacement for electro-mechanical relays. However, over the period of time with addition of process control and networking capabilities, PLCs have gained greater functionality. With advancement in user interfaces and SCADA systems, PLCs have become more popular for sequence interlocking and integrating controllers.
PLCs are used with Personal Computers for batch management/control applications. Application of PLCs for batch control application is explained with help of an example.
Let us consider an example of automation of fermentation process. The...
