Derived from Invensys, the Foxboro A2 automatic system is a DCS system that meets a variety of market needs. It can be specified to control a process device or required to automate a plant. It can complete all users of a variety of applications, continuous process control and discrete manufacturing.

This is the economical, simple, and scalable solution that users have been expecting. It can be used as a simple I/O system, monitoring system, up to loop control, data management, operation panel display and implementation of redundant control, and provides a complete network system. In case of problems, users can get system support from any Foxboro service around the world. And its structured system ADAPTS to users’ needs and budgets. Invensys’ new ArchestrATM structure ensures that the system can grow with your needs and allows you to incorporate a variety of third-party solutions that can be used to increase your factory productivity in the future.

1 Overview of the system network

The Foxboro A2 communication network is based on the Open Systems Interconnection (OSI) standard defined by the International Organization for Standardization (ISO) and complies with the IEEE specifications. The system network includes the factory information network, the device level network (commonly referred to as the system network), and the I/O network. The main structure of the system is as follows:

ELIN or Modbus/TCP, the redundant control network of Foxboro A2 system, uses IEEE802.3 fast Ethernet technology to connect the control station, engineer station and operator station of Foxboro A2 system to complete the communication and data exchange between the stations. The maximum transmission rate is 100Mbps. The communication medium is optical cable or twisted pair, and the maximum transmission distance of each section is 10000m (optical cable). A2 system control station and I/O station are connected by the most popular field bus Profibus-DP in the world, Profibus-DP conforms to EN50170 standard, is specially used to connect the decentralized control equipment of the international standard communication bus, it can meet the high-speed transmission, high reliability and anti-interference requirements of the occasion. The transmission rate is 9.6-12 MBPS.

2I/O System -2500 series
The 2500 Series from Invensys is a scalable I/O system with high performance, high precision and high usage. The 2500 Series is a key component of Invensys’s advanced DCS framework solution, the Foxboro A2 Automation System, providing a wide range of cost-effective advanced features, including PID control with automatic tuning and gain scheduling.

3Foxboro A2 Controller -T940 and T2550 systems
The CPU of the control processor (T940 and T2550) adopts 32-bit Pentium chip, which can realize continuous quantity, sequential quantity and ladder logic control functions. T940 Process Controller Key Performance:

· Powerful control strategy engine can support continuous control and sequential control
· Redundant processor with optional automatic seamless switching
· The processor has online replacement and automatic initialization capabilities
· Support Ethernet, ARCnet and serial control network
· peer-to-peer control network for communication between nodes and controllers
· Support both Profibus DP and Modbus RTU open I/O networks
· Support redundant I/O communication
· Distributed I/O saves wiring costs

Control variables of industrial processes with time-tested algorithms (numerical calculations that perform specific functions), including continuous control strategies and procedural control strategies. Continuous control policies can be configured simply by connecting various functional blocks, including advanced control blocks, programming blocks, ISA-88 standard blocks, and user-defined functional blocks. The program control strategy uses the powerful and intuitive SFC flow chart configuration in IEC61131 to complete the requirements of batch processing and multi-program running at the same time.

1.4 Engineering development tools
The Project DeveloperTM and Project StudioTM software are high-performance engineering tools for process automation control and are an important part of Invensys Group’s advanced solution beyond the DCS framework, the Foxboro A2 automation System. These tools provide an engineering-oriented integrated development environment that provides a cost-effective, single-point solution for system configuration and commissioning.

Project Developer and Project Studio software Features:
· Engineering oriented integrated development environment
·HMI uses Wondeware INTOUCH
· A set of tools designed for system configuration and trial operation
· Single point configuration function
· Lots of examples and automatic build features
· Centralized relational database
· Have online help function of online materials
· Remote access via Modem/ network
· Automated application filing
· Component of Foxboro A2 automated system
·Windows 2000/XP