High-precision control for superconducting electron linear accelerator
European XFEL, Germany
A wide range of products and solutions is required to react flexibly and precisely to rapidly changing requirements in the automation of machines and plants in the scientific environment. In large scientific research facilities, for example, a measurement setup must be able to change at any time and at short notice. At the same time, the next setup should be quickly available and meet the highest requirements with regard to precision and resolution. This can only be achieved with a flexible control platform, such as Beckhoff has been offering with PC-based control for 40 years now. As a technology-driven company, Beckhoff continuously surprises its customers with innovations that represent a qualitative leap in automation, enabling them to benefit from this technological advantage.
With PC-based control, all functions run in software, from the classic PLC and motion control to measurement and safety technology. As a result, the controller can quickly be adapted to changing requirements. TwinCAT is not only the software and engineering platform for all automation processes, but also supports the programming of high-level language parts. The extensive range of EtherCAT Terminals, which includes various I/O signals, interfaces, fieldbus masters/slaves, measuring options and motor controllers, is also ideally suited for applications in scientific systems and devices. Due to its modularity, the I/O system supports a lean and flexibly expandable control architecture; the retrofitting of functions by directly connecting additional terminals is possible at any time. The scalability of all Beckhoff components in terms of performance, design and price also allows a controller design that is precisely tailored to the application.
Beckhoff technology highlights for applications in science
High flexibility in scientific systems and devices with PC-based control
With PC-based control, Beckhoff offers comprehensive system solutions in various performance classes for all areas of automation. The basic system is based on a high-performance Industrial PC, a high-performance fieldbus connection with the connected peripheral devices for sensors and actuators, and the software for engineering and real-time control. The control platform is supplemented by an extensive portfolio of drive components. Precisely scalable and modular, the Beckhoff control and drive technology can be optimally adapted to a wide range of applications. The TwinCAT automation software bundles all necessary machine functions such as PLC, motion, robotics, measurement technology, vision, communication, IoT functions and the HMI operating software in a single software package. This results in a high functional benefit and allows the realization of cutting-edge technology while at the same time keeping costs low.
All PC tools and communication options, such as Internet access, sending emails from the PLC, etc., can also be used in the industrial environment; communication into the controller is realized via defined interfaces. Customer software is also addressable via this interface. Support for common fieldbus systems and software protocols also guarantees universal horizontal and vertical communication: from the networking of the individual machines to the IT level and the cloud.
Synchronization of distributed systems with PC-based control and EtherCAT
In spatially extensive installations, such as particle accelerators, observatories, etc., the challenge is to control actuators synchronously. For system-wide data collection, it is important to know exactly when the data is generated; only in this way advanced analysis methods such as condition monitoring or the learning of neural networks are possible. The goals are better control and better further processing of data. Depending on the application requirements, Beckhoff offers different methods of synchronizing distributed controllers with different accuracies:
- Synchronization in the microsecond range via EtherCAT
With the EtherCAT fieldbus system developed by Beckhoff, the "Distributed Clocks" function makes time synchronization in the microsecond range possible. The distributed systems are connected to an EtherCAT master that manages data exchange and synchronization.
- PTPv2 (Precision Time Protocol) for connection to a PTP clock
With the Beckhoff EL6688 EtherCAT Terminal, a PTP clock can be connected to a controller. Controllers that are not connected to one another via a real-time EtherCAT connections can be synchronized with one another via the network protocol. Synchronization takes place on the basis of high-precision clocks. The time is transmitted using the PTPv2 protocol. The topology can be transferred for a network prepared for "Transparent Clock" or a point-to-point connection.
- NTP (Network Time Protocol)
In distributed systems where time synchronization in the millisecond range is required, a pure SNTP solution can be used. The clocks of the controllers can be synchronized via an SNTP server using the TwinCAT-3.1 function "Corrected Timestamps". In order to achieve improved accuracy and load balancing, a controller can query the time via SNTP and provide it to additional Beckhoff controllers by means of ADS.
Beckhoff product highlights for applications in science
Highly dynamic, modular, scalable: the Beckhoff drive technology
In combination with the motion control solutions offered by the TwinCAT automation software, Beckhoff drive technology represents an advanced complete drive system. Modular and highly scalable, it offers the right solution for every application area and every performance requirement: from the ultra-compact servo terminal for "small drive technology" to the AX8000 and AX5000 EtherCAT servo drives for the mid to upper performance class. The integrated control technology of the AX series supports fast and highly dynamic positioning tasks. The extensive range of linear and rotary servomotors is optimally tailored to the servo drives and is suitable for multi-axis positioning tasks with high dynamics and accuracy. The AM8000 motor series is characterized by the One Cable Technology: It combines power and feedback signals in a standard motor cable, thus reducing material and commissioning costs and making machines and plants more compact and lighter. Additional encoder signals (BISS-C, EnDAT 2.2 and others) can be connected via an optional multi-feedback card. The EtherCAT servo terminals represent an inexpensive and compact alternative for applications where only low forces are involved. Solutions up to 8 A are available in the I/O system as well as the option to connect stepper, servo, DC or AC motors in IP20 or IP67. The stepper motor controllers using TwinCAT Motion Control and the EtherCAT servo drives in terminal format are optimally suited for use in research facility operation.
One Cable Technology minimizes cable and mounting costs
Each cable is one too many, provided there is a technologically better alternative to it. Cables are a not inconsiderable cost factor in machine and plant construction – they have to be procured, configured, connected and, in the worst case, assembled. In subsequent operation, cables are a sources of error, especially when they are moved. Bending and torsional movements in drag chains and robots lead to wear. EtherCAT P significantly reduces these expenses. The one-cable fieldbus integrates the EtherCAT communication as well as the system and peripheral voltage in one cable and enables power supply forwarding via the devices. EtherCAT P is the optimal bus system for sensors, actuators and measurement technology in scientific automation and its large and distributed research facilities. Components, terminal boxes and machine modules only need to be connected via one cable. Modular machine and plant concepts can be implemented with noticeably reduced installation and commissioning effort and very high flexibility.
All the benefits of EtherCAT are retained, such as the free topology selection, high speed, optimum bandwidth utilization, the processing of telegrams in passing, highly precise synchronization, extensive diagnostics, etc. For distributed sensors in large, extensive systems, terminal boxes can be completely dispensed with using the EtherCAT Box modules in IP67, if necessary.
EtherCAT P: the high-speed fieldbus with a "one cable advantage":
- optimized for the direct connection of EtherCAT P devices in the field
- less wiring work combined with time savings
- fewer sources of error
- smaller sensors and actuators due to elimination of the separate supply cables
- simple connection of components
TwinSAFE: the integrated control and safety solution
In TwinSAFE, Beckhoff has implemented a universal safety concept that integrates safe functionalities into the standard control platform: from the PLC to I/Os to drive technology. All safety functions such as emergency stop, safety door monitoring, two-hand operation, safety mat evaluation and muting, safe position, safely limited speed, etc. can be programmed and configured on the integrated TwinCAT engineering platform. Safety technology is seamlessly integrated into the terminal segment via the TwinSAFE I/O modules, whereby safe signals can be mixed with standard signals as required.
The typical safety functions can be programmed or configured according to the safety requirements in a TwinSAFE Logic Terminal, e.g. EL6910 or the EK1960 compact safety controller on the basis of standard safety function blocks. All Beckhoff safety controllers are suitable for applications up to SIL 3 according to IEC 61508 or Performance Level e of ISO 13849-1. The safety controllers support complex, safe analog evaluations, e.g., for the safe limitation of process variables such as pressures, temperatures or speeds of frequency-controlled drives.
With the help of the TwinSAFE SC technology, it is possible to qualify standard signals for safety tasks in any network or on any fieldbus. For this purpose, corresponding EtherCAT Terminals are available for the acquisition and safe transport of these signals via EtherCAT.
Large networked plants pose major challenges for all parties involved, especially with regard to safety technology. Many networked machines and plant sections with their own safety zones, spread over large areas, hinder the overview and make subsequent extensions and adaptations a herculean task. TwinSAFE offers the option to completely or partially decentralize the safety application as required. Each machine, each plant section or, if necessary, each unit can easily be equipped with its own safety logic. The TwinSAFE logic is part of every safe input or output terminal and also of many drive components. This makes it easy to create autonomous safety areas that can communicate with one another. If necessary from a process point of view, sections can be switched off interference-free during operation, even though they are a part of the safety chain. During the use of the plants and commissioning, individual units and machines can be verified and validated in terms of safety by the respective department.
