System 800xA is ABB’s DCS Platform that allows operators and engineers complete overview of the automation process. It encompasses everything from the controller programming all the way to the operator workstation. It gives the operator access to the all the information about the various aspects of a particular instrument or machine just at the click of a button.
A system architecture is a conceptual model that describes the structure and behavior of a proposed system or an existing system. The 800XA system architecture is divided into different levels that correspond to the functionality of the devices on that level.
There are different levels of an ABB 800xA DCS automation system. These include:
- Field Network—Here you have the field devices like Variable Frequency Drives, Transmitters, Pumps, Valves etc that send or receive signals from the field to the controllers or IEDs. The devices can send the signals to the controllers or IEDs through hardwired signals (24V, 4-20mA) or Fieldbus Protocols like PROFIBUS, Modbus RTU etc.
- Control Network—The control network is used for communication between controllers on the network. This way, a controller can share information about its variables like (transmitter values, power parameters etc) with other controllers on the network. This makes the system behave like a complete unit. Different communication protocols like PROFINET, PROFIBUS, MODBUS can be used for communication on the control network depending on the manufacturer. ABB uses the MMS protocol (Manufacturing Messaging Specifications) for communication on the control network. The control network is also used for communication between the controllers or IEDs and the 800xA DCS servers. There are different servers that can be used depending on their purpose. The main purpose of the servers is to acquire information from the control network for logging, analysis, visualization and so on.
- The Client Server Network—The client server network is used for communication between the 800xA DCS servers and the operator workplace for visualization, and between the servers and the engineering workplace for controller programming and tag configuration. The protocol most used here is OPC and for newer systems OPC UA.
- Plant Network—The plant network is used for communication between the 800xA system and the plant IT/Business Systems.
Understanding the system architecture of control and monitoring systems is important for automation engineers who are going to work in large process plants.