In the early stages of process automation control development, plant managers had two basic choices: Distributed Control Systems (DCSs) or Programmable Logic Controllers (PLCs). Despite their similar functions, they differ significantly, each with its own advantages and disadvantages. Ultimately, whichever you choose, you will always pay a price. Distributed Control Systems A distributed control system is a sophisticated, single-processor network system that controls various aspects of a process system. These systems are typically very complex and expensive, using proprietary hardware and software, including control languages, meaning only the manufacturer can provide after-sales service and technical support. Once installed and in use, they are difficult to adapt to changes in process requirements over time. However, they can handle the largest and most complex process operations, making them primarily used in continuous process industries such as energy and power, oil and gas, water and wastewater treatment, and pulp and paper manufacturing. Programmable Logic Controllers Programmable Logic Controllers (or PLCs) are small but fast computers used to control the process flow of single or multiple practical applications, such as equipment in a process system. It replaces the hard-wired relays that required manual rewiring after each change in process flow or product, overcoming the high cost and low efficiency of traditional relays. With a PLC, you only need to reprogram it to complete the entire operation. In fact, early PLCs used ladder logic, a language that reflects relay circuit diagrams, making them easy for traditional engineers to understand. DCS systems are rigid, while PLC systems are flexible. DCS systems are large, self-contained systems, while PLC systems are modular, scalable systems, providing excellent solutions for small to medium-sized process operations, especially for process systems in batch and discrete production departments such as food and beverage, personnel safety, and life sciences. Because of its modular components, PLC systems are generally cheaper, at least in the early stages of engineering. However, once engineers have assembled all the components into a system, its price can be comparable to or even exceed that of a DCS. The Concept of Hybrid Control Systems Over the past decade, long-established DCS and PLC companies have turned to what is collectively known as "hybrid control systems," where they attempt to combine the power and complexity of DCS systems with the flexibility, openness, and low cost of PLC systems. To this end, DCS companies have reduced the footprint of their systems, while PLC companies have begun integrating their components to create more sophisticated systems. However, despite many attempts achieving commercial success, these "hybrid systems" have never quite reached the original vision of hybrid control systems. For example, DCS hybrid control systems cannot be manufactured in a sufficiently modular fashion for OEMs and end customers, nor do they offer enough scalability and flexibility to handle applications of varying sizes. Furthermore, the speeds of high-speed sequential control or discrete processing (sometimes measured in tens of milliseconds) are too fast and difficult to adjust for DCS hybrid control systems, making applications such as packaging, metal forging, or simple motor control difficult or even impossible to implement. Therefore, mixed industries with batch, continuous, and discrete environments, or large continuous processing plants requiring high-speed sequential control, still require another control system for their discrete domains, resulting in numerous additional costs, integration problems, and increased training and maintenance expenses. Many long-established PLC systems attempting to develop hybrid control systems fail to provide true system performance and lack system services, such as the inability to uniformly define variables and manage system alarms/events. Whether from traditional DCS or PLC technologies, most such systems cannot be tightly integrated with the information layer. Increased costs due to the use of multiple databases cannot be avoided, while a tight integration of the information and control layers can effectively control and optimize products and improve operational performance. Introducing visibility into process operations is not only economical but also simpler. The concept of a hybrid control system allows for a tighter integration of the information and control layers . Now, GE Fanuc's Proficy Process Systems, a system employing a hybrid control system concept, is an automation control system that combines the power and efficiency of distributed control systems with the flexibility, openness, and price advantage of programmable logic controllers. By integrating Proficy software's inherent hierarchical structure into process control systems, product optimization, analysis, and production management become simpler and clearer. Partnering with GE Fanuc to address your process control needs will give you a competitive edge in today's global economy: • Results. GE Fanuc's process solutions allow you to improve system performance, increase output, and reduce overall costs. • Experience. As a long-standing leader in process technology, GE Fanuc's professional services team, along with its network of qualified system integrators, is dedicated to providing the industry-specific, application-specific expertise needed to develop solutions tailored to your business. • Freedom. Our solutions remove the limitations of traditional DCS and PLC systems, giving you the freedom to configure, allocate, plan, and maintain your systems as you wish. • Modern solutions. Not only are our technologies cutting-edge and industry-leading, but our flexible service and support models are also innovative, allowing us to customize solutions to meet your business needs.