The ongoing changes in hardware have led to homogenization. Today, PLCs should no longer be compared based on factors like CPU speed, storage capacity, number of I/O points, or programming language. As a core product in industrial control, the PLC has undergone significant changes, all thanks to the revolution brought about by IT technology. Storage is becoming increasingly cheaper and larger, allowing for the storage of massive amounts of real-time data on PLCs. CPUs are becoming faster, easily solving problems that were previously unsolvable. Displays are becoming more diverse and abundant, and hardware demands are increasing in speed. However, standardization and generalization are the future trends. Therefore, competition is no longer about the hardware itself; the era where performance determined everything is coming to an end.
The era of PLCs needing to be more open and integrate various technological functions has arrived. This includes motion control, safety, hydraulics, robotics , CNC, real-time communication, FDT, wireless Ethernet, GPRS, etc., which are all widely penetrating control. PLCs need to become more open in order to survive in future competition.
Technology is converging – the widespread application of PC technology has infinitely expanded the power of controllers, while rich software applications have also made CPUs faster and more powerful. IT technology has provided all of this. Intel architecture embedded CPUs have been widely used in industrial control, and concepts such as PAC, PCC, PLC, PC, DCS, and SCADA are merging with each other and gradually interfacing with professional technologies such as GIS and SQL Server. Control technology is forming an integrated whole. Individual PLCs or PCs have become flattened in the needs of the entire control application, and the boundaries are beginning to blur. The concepts of dedicated controllers and general-purpose controllers are also becoming blurred. The world is moving towards convergence.
Simply listing and comparing the performance and functions of PLCs cannot reflect the full picture of high-end PLCs. It only shows a part of the PLC. Instead, it is necessary to take into account the industry's needs, the product design architecture and philosophy of high-end PLC manufacturers, and other factors.
Driving forces for the development of high-end PLC technology
1. The IT industry's contribution to the automation industry
1.1 Makes hardware more universal
With the development of IT technology, the processing power, communication speed (Ethernet technology), storage and expansion capabilities, software function blocks (OPC), diagnostic and maintenance capabilities (IT-based maintenance), and display capabilities of CPUs have all been greatly improved. Furthermore, the development of IT technology has led to a continuous decrease in hardware costs, and competition in the IT industry has made chips easier to obtain and cheaper.
1.2 Standardization and Modular Design
In order to reduce the production and manufacturing costs of the system, PLC products are constantly moving towards modular and standardized design.
Therefore, the development of domestically produced PLC products should always pay attention to the role of IT technology in promoting the development of automation, and to how IT technology can be integrated into automation technology.
2. The demand for complex control drives the development of PLCs. Whether it is PLC, PCC, or PAC technology, their development aims to meet the control needs of more complex machines and production sites. Distributed computing puts forward new requirements for buses, and production integration is constantly increasing the demand for software SCADA and DCS. PLCs will take on more functions in these areas.
PLCs were initially developed primarily for logic control. However, with the advancements in IT, communication, and sensor technologies, as well as the increasing demand for field data in production management—specifically for tracking production processes and analyzing factors influencing technology and quality—the need for such data has continuously grown. Furthermore, environmental and safety requirements have driven the development of safety technologies. These factors have all influenced the control requirements of PLCs.
2.1 Complex Algorithm Design
Today, in the field of machine control, there are some applications similar to PID control and process algorithm design (color matching, tension, weighing, drafting, unwinding, and rewinding) in process control that require PLCs to have strong algorithm design and processing capabilities. For example, B&R's PCC can be programmed in C or C++, which makes it easier to design complex algorithms. Bachmann's PLC can be programmed in C, C++, and Java, while SoftPLC's SoftPLC can also be programmed in Java.
2.2 Motion Control
Because older machines had fewer motion control actuators and typically used dedicated motion controllers, motion control is now more widely used in various mechanical manufacturing fields, as well as in papermaking, beer production lines, tobacco, and other industries. This has placed higher demands on motion control systems such as electronic gears, electronic cams, and positioning control. For example, SIEMENS' T-CPU series can handle motion control tasks, while B&R's PCC can directly control servo drives via a bus to implement various motion control algorithms.
2.3 Safety Technology
With the increasing demand for personal and equipment safety, various PLC manufacturers have developed SafetyLOGIC products designed for safety applications. For example, SIEMENS' 317F and 319F CPUs are designed for safety applications, as are ABB's PLUTO safety PLC and Rockwell Automart's. B&R has developed the SafetyLOGIC PLC.
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