Qicheng Automation was established in 2012, focusing on training projects in Siemens PLC programming system integration, industrial robot programming, EPLAN electrical design, vision, and other training and technical services. Official website: www.qichengplc.com
Embedded systems are often used for developing relatively independent products;PLC is mostly used for application-oriented project integration.In summary, whether to usePLC or embedded systems should be based on the characteristics of the project, and cannot be generalized. Let’s analyze this below.
(1) When to Use Embedded Systems
If you pay close attention, if it’s a standard industrial product produced in large quantities and requires some complex calculations, embedded systems are usually used. For example, frequency converters, standard industrial robotic arms, and some specialized equipment.Some products are mass-produced. Initially, when using embedded systems for specialized research and development, a certain amount of financial and human resources need to be invested for research and debugging. Once the R&D is successful, the initial R&D costs will be directly allocated to each individual product in later mass production, greatly reducing the overall R&D cost per product. If only mass-producing equipment, it can be said that embedded systems are considerably cheaper in hardware costs than PLC.Additionally, in many scenarios, using PLC is not ideal. For instance, some products require a lot of complex calculations, such as the extensive motor drag and control algorithm calculations within frequency converters, or the SLAM navigation algorithms of automated handling robots. These can only be implemented in high-performance embedded systems, as PLC cannot compute such complex algorithms.Moreover, in some cases, PLC cannot be used. For example, in frequency converters or a compact industrial device, although PLC can be implemented, the size is a concern. At the very least, a voltage regulator module is needed, several input/output modules, and a communication module. If all these components are crammed into a standard compact industrial device, it would look unreasonable.Furthermore, if a standard industrial product is controlled solely by PLC, there are usually many competitors in similar products. If an embedded system is used, relatively speaking, there are fewer competitors.Moreover, control systems built with PLC are easily replicated. Just opening the control cabinet reveals how the control system is constructed, with several input/output modules and what sensors are connected, making it very clear.In contrast, embedded systems require designers to design their own peripheral integrated circuits, which provides better protection.A high-value-added industrial device that is controlled only by PLC, if there are few competitors, it certainly does not mean that their control system has a significant difference from others. The advantage must lie in mechanical structure, patent protection, or process control.On the other hand, control systems that must use embedded systems often have higher technical content and more complex algorithms. The embedded system includes embedded programs, which adds significant value and creates a certain technical barrier.
(2) When to Use Industrial PLC
In real situations, various industrial devices need to be deployed in specific project applications. When it comes to projects, they vary greatly. The most important requirement for industrial projects is “stability.” Anyone involved in industrial control knows that companies producing PLC products are definitely not small companies; their PLC products are highly popular and are applied across various industries and fields, with countless case studies. PLCs can be found in power transmission and distribution network control systems, automatic storage systems, certain devices in the petrochemical industry, and in steel rolling control systems. Each of these projects has already helped other users validate the stability of this PLC.Imagine if a company wins a project with a construction period of 100 days. If Group A uses an embedded approach to develop the control system, they are designing circuit boards, while Group B, using PLC, is already writing programs into the purchased PLC modules.Moreover, this does not even consider how to control outputs and what coupling circuits to use for input collection in embedded systems. For PLC, none of this is needed; they only need to select suitable modules from the PLC manufacturer and insert them into their cabinet.
