Distributed Control Systems (DCS) & DCS Migration

A Distributed Control System (DCS) is a control system for a process or plant, wherein control elements are distributed throughout the system. This is in contrast to non-distributed systems, which use a single controller at a central location. In a DCS, a hierarchy of controllers is connected by communications networks for command and monitoring.

A DCS typically uses custom designed processors as controllers and uses both proprietary interconnections and standard communications protocol for communication. Input and output modules form component parts of the DCS. The processor receives information from input modules and send information to output modules. The input modules receive information from input instruments in the process (or field) and the output modules transmit instructions to the output instruments in the field. The inputs and outputs can be either analog signal which are continuously changing or discrete signals which are 2 state either on or off . Computer buses or electrical buses connect the processor and modules through multiplexer or demultiplexers. Buses also connect the distributed controllers with the central controller and finally to the Human–machine interface (HMI) or control consoles. The elements of a DCS may connect directly to physical equipment such as switches, pumps and valves and to and HMI via SCADA. The differences between a DCS and SCADA are often subtle, especially with advances in technology allowing the functionality of each to overlap.

Portland Engineering DCS & DCS Migration controls engineering services are dedicated systems used to control manufacturing processes that are continuous or batch-oriented, such as gas storage and extraction, power generation & cogeneration, metals production, and food and beverage manufacturing. Our DCS are connected to sensors and actuators and use setpoint control to control the flow of material through the plant. The most common example is a setpoint control loop consisting of a pressure sensor, controller, and control valve. Pressure or flow measurements are transmitted to the controller, usually through the aid of a signal conditioning I/O device. When the measured variable reaches a certain point, the controller instructs a valve or actuation device to open or close until the fluidic flow process reaches the desired setpoint. We work on large facilities that routinely have many thousands of I/O points and employ very large DCS. Processes are not limited to fluidic flow through pipes, however, and can also include things like wood processing facilities and their associated quality controls, variable speed drives and motor control centers, metal processing facilities, and many others.

Our DCS are usually designed with redundant processors to enhance the reliability of the control system. Most systems come with displays and configuration software that enable the end-user to configure the control system without the need for performing low-level programming, allowing the user to better focus on the application rather than the equipment. Considerable system knowledge and skill are required to properly deploy the hardware, software, and applications in a DCS, so consider contacting PEI if you have further questions.


Advanced Control | Automated Assembly | Batch Control & Batch Processing | Computer Aided Design (CAD) & Computer Aided Manufacturing (CAM) | Cloud Based Applications & Software | Control System Design | Control Panel Design | Data Processing, Collection, Reporting, Management & Analytics | Distributed Control Systems (DCS) & DCS Migration | Dedicated Controls | Discrete Control | Energy Management | Ethernet/IP | Factory Automation | Fault tolerant Systems | Field Service | Flow Control | HMI/OI | Industrial Engineering | Industrial Ethernet | Information Integration | Information Systems | Input & Output Modules | Installation & Startup | Level Control | Machine Design, Control, Repair & Maintenance | Manufacturing Execution Systems (MES) | Modbus TCP | Motors, Drives & Motion Control | Networking & Communications | Programmable Automation Controllers (PACs) | Programmable Logic Controllers (PLCs) | Pressure Control | Process Control | Process Engineering | Product Tracking, Identification, RFID, Barcodes & Matrix Codes | Profibus & Profinet | Project Management | Pumps, Compressors & Turbines | Supervisory Control and Data Acquisition (SCADA) Systems | Sensors | Systems Engineering | Radio, Wireless & Cellular Telemetry | Temperature Control | Maintenance Training & Education | Operations Training & Education | Virutalization | Wireless | Wireless Ethernet