System Architecture

What are the basic elements of a control system?

Basic parts of system architecture are shown below

What is system architecture with example?

An architecture diagram is a graphical representation that depicts the physical implementation of software system components. It illustrates the overall structure of the software system as well as the relationships, constraints, and boundaries between each component.

The control system architecture illustrates the architecture of the plant control systems and the interface between systems required for the overall operation of a process plant.

The level of functionality, complexity, and safety of a plant determines which Control System is needed. This could include a process control system, safety instrumented system, HIPPS, fire and gas system, and package unit control system.

Control system architecture drawing must also show supervisory level equipment like operators workstation, engineering workstation, HMI server, OPC server, historian server, control panel like ESD panel (push button and lamp), fire and gas matrix, and network equipment.

The architecture of the control system must clearly define the locations, including the main locations, remote I/O locations, indoor/outdoor locations, and the limit between the control room and the building.

Additionally, the major control, Ethernet, and communication cables are displayed and described.

What is the use of a system architecture diagram?

• Visual overview making it good to communicate about ideas and key concepts in a way that everyone can understand. 
• Demonstrate how current services are organized and exposed both internally and externally. 
• Indicate how third-party integration will work with the system.
•  Describe how the system will be protected and managed.

The control system is a communication system made up of controllers and links.  The structure of the plant should be reflected in the control system.

In an ideal situation, each part of the plant should have its own controller that talks to the controllers of other, related parts, just like the parts themselves talk to each other.

Busses and processors in industrial plants

Printing Architecture

Production management system

Centralized (Hierarchical) Control Architecture

Architecture that is traditional, hierarchical, and centered. The central computer only watches and sends commands to the PLCs.

Decentralized Control System 

All controllers can communicate directly with each other (without going through a central master), and the only limits are throughput and modularity.

Advantages of Architecture Diagrams

1. Improve understanding: The diagrams provide an overview of the system, so everyone understands how the various components interact when determining the impact of updates and new features on the system.
2. Enhance communication: Software architecture diagrams help everyone understand the game plan by aligning project goals across all teams, departments, and stakeholders. They also keep stakeholders up to date on the overall progress of the project.
3. Effective cooperation and identify areas for improvement: Visualizing the application system structure allows your team members to discuss the design, identify patterns that work well, look for major weaknesses, and identify areas for improvement in a collaborative effort.

The picture below is an example of a system architecture drawing

The functional hierarchy model shows how a manufacturing company has five levels of functions and activities.

Level 0 describes the physical processes themselves.

Level 1 describes the tasks involved in sensing and evolving physical processes. In automation systems, level 1 elements are physical sensors and actuators that are linked to level 2 control functions.

Level 2 describes the activities of monitoring and controlling the physical processes. In automated systems, this includes controlling and monitoring equipment. Level 2 automation and control systems have real-time responses measured in subseconds and are usually made with Programmable Logic Controllers (PLCs), Distributed Control Systems (DCS), and Open Control Systems (OCS)

Level 3 describes the activities that coordinate production and support resources to make the desired end products. It includes both workflow “control” and procedure “control” through the execution of recipes. Level 3 usually works with time periods of days, shifts, hours, minutes, and seconds. Production, maintenance, quality, and inventory operations are also part of level 3 functions. These are called MOM. MOM’s production operations activities are directly supported by level 3 activities and functions that are directly integrated and automated.

Level 4 describes the business tasks that are needed to run a manufacturing company. Activities related to manufacturing include making the basic plant schedule (for things like material use, delivery, and shipping), figuring out how much inventory to keep on hand, “controlling” logistics, and “controlling” material inventory (making sure materials are delivered on time to the right place for production). Business Planning and Logistics is the name of Level 4. Most of the time, Level 4 works in terms of months, weeks, and days. Logistics systems that use enterprise resource planning (ERP) are used to automate level 4 tasks.