There are Sercos-capable products for almost all automation applications
More than 130 providers cover a wide range of products and services: including controls, drives, frequency converters, sensors, decentralized I/O periphery, infrastructural components, other peripheral devices, image processing solutions, hard- and software components, development tools and testing and engineering solutions.
Products of Sercos members are highlighted red.
In addition to specialized device manufacturers, there are also numerous complete solution providers for different industries such as robotics, machine tools, packaging and printing machines and general automation.
Various application reports show how companies use Sercos-capable products, what the challenges were and how they were met. There are references from various companies from a wide variety of industries under Applications. Interested parties will find the appropriate solution for every automation application!
All Sercos products can be certified via independent certification centers. Details of the certification requirements and the process, plus addresses of independent certification centers are found under Certification.
In addition, companies with products that are almost ready for the market or products with newly implemented Sercos features have the opportunity to participate in the Sercos PlugFest that normally takes place twice a year and gives companies the opportunity to test their products with other manufacturer's devices in order to ensure both forward and backward compatibility .
Sercos was developed as a digital drive interface by an industrial consortium with the support of ZVEI and VDW in the mid-1980s. The first generation supported 2 and 4 Mbit/s transmission rates and initially was used mainly with demanding tool machine applications. In the following years, Sercos was successfully deployed in a wide variety of applications around the globe. In 1995, Sercos was recognized as IEC standard 61491. In 1999, the second generation of the standard followed. The transmission rate was increased to 8 and 16 Mbit/s and the service was expanded to include asynchronous data transmission. Since 2001, this technology has been available based on the SERCON816 ASIC, with backward compatibility with the first generation ensured. Collision-free data transfer based on a time slot process and an extremely efficient communication protocol enable very high performance with a deterministic time response. For example, up to 40 axes can be controlled and synchronized in hard real-time at a 1 msec. cycle time with a jitter of less than 1 µs. In addition, the use of a fiber optic ring ensures very high noise immunity and transmission robustness.
Numerical controls (NC) are devices which control production machines by translating control commands into work and motion sequences. Numerical controls have been equipped with computers since the beginning of the 1970s, which is why numerical controls are usually called CNCs (Computerized Numerical Controls) today. The development and maintenance of a CNC is a demanding and expensive task. Over the past 10 to 15 years, this has led to a severe decrease in the number of CNC providers and the number of machine manufacturing companies who build their own CNC. Manufacturers of CNCs who cover a niche market and therefore only sell a limited number of units can only remain competitive through a combination of products from third-party providers (in particular drive systems) and through the consistent application of industry standards. A different approach is adopted by universal providers who cover a very wide spectrum of machine tools with a full package which consists of CNCs and drives. Due to the higher volume of units, these providers can assert themselves in the market more easily. However, the products from these universal providers often cannot fully cover applications with specific or complex requirements.
A CNC machine can be programmed in a variety of ways. The DIN 66025/ISO 6983 programming language has established itself as standard in the industry, unifying the construction of a program code and certain basic commands. New programming concepts, such as STEP-NC, rely on a universal procedure chain from the CAD system to the CNC.
The device technology in the area of control technology has changed significantly over the past 10 to 15 years. More and more, proprietary hardware is being replaced by PC-based systems. Many providers have begun integrating the previously separate device technology for NC and PLC in the form of one or more PC expansion cards. However, in most cases, the real-time critical control software is still processed by a separate processor – independently from the PC. A small number of control manufacturers offer purely software-based NC systems in the form of a single-processor solution. Here, a real-time expansion for the Windows operating system ensures that a suitable real-time environment is provided for the NC software.
Modern CNCs offer machine manufacturers a wide variety of possibilities for carrying out individual adjustments for tailor-made requirements and applications in the operating area (HMI = Human Machine Interface) or, additionally, in the so-called NC core area. The connection to external peripheral equipment is usually carried out via a standardized bus system.
Numerous CNCs on the market support Sercos as an open communication interface to the electrical, pneumatic and hydraulic drives, and other peripheral equipment. In addition to specialized CNC manufacturers, there are also providers who offer a complete automation package for machine tools.
A PLC (programmable logic control) is a programmable control that is used to control or regulate a machine or system and is programmed on a digital basis. A PLC possesses input and output interfaces by which sensors and actuators can be addressed to monitor, control and regulate processes. The sensors and actuators can be connected to the PLC directly or via a bus system (e.g. Sercos, Profibus).
A PLC can be implemented in a large variety of ways, for example as a single device (hard PLC), as a PC plug-in card (slot PLC), or as a software emulation (soft PLC). Modern PLC systems are classic micro-controllers with their own CPU and basis software that also allows the word-by-word connection of I/O signals. The basis software consists of a real-time operating system and PLC-specific software components. Newer systems go a step further here. These combine the conveniences and advantages of a PLC with those of an industrial PC (IPC) and are referred to as PAC systems (programmable automation controller). Due to their simple programming capabilities, these systems allow both increased user comfort and an improved and faster connection at their place of use. Modern PLC controls also increasingly integrate functional components for motion control or assume safety functions (safety PLC).
Programmable logic controls are mostly programmed with special (often graphic) programming languages as well as specially adapted high-level languages, which make possible the programming of highly complex processes in automation. The IEC 61131-3 standard includes the definition of the Sequential Function Chart (SFC) language, used to structure the internal organization of a program, and four interoperable programming languages: Instruction List (IL), Ladder Diagram (LD), Function Block Diagram (FBD) and Structured Text (ST).
Depending on the efficiency of the PLC and the programming device, not all languages need to be available. Conversion between languages is dependent on the manufacturer, i.e. not possible or possible only with limitations. Many programming environments also offer the opportunity to use additional languages, such as C. As an international manufacturer- and product-independent organization, PLCopen defines complementary functional components on the basis of IEC 61131-3 that result in a significant increase in efficiency in the development of application software.
Numerous PLC controls are offered on the market that are equipped with a Sercos interface for connecting drives and other peripheral devices, also including various soft PLC products.