PC-based control for highly efficient and flexible warehouse and distribution logistics

PC-based control meets the requirements of demanding warehouse environments

Traditional PLCs cannot keep pace with the technological advances of today's intelligent systems for warehouse and distribution logistics, as they can only be extended with a lot of expenditure through additional gateways and the interplay of various "black box" controllers. This leads on the one hand to additional hardware, software and engineering costs and on the other to cost-intensive service and spare parts maintenance of the systems. The development towards intelligent and modern warehouse technologies requires the use of PC-based control technology.

The bases of the PC-based control technology are the powerful Beckhoff Industrial PCs and EtherCAT as a high-performance fieldbus connection, together with the connected peripheral devices for sensor and actuator systems as well as the TwinCAT 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. As if from a construction kit, the user can assemble a suitable control solution for his system or plant type and dimension it according to performance requirements.

The Industrial PC portfolio ranges from entry-level controllers with ARM processors to multi-core industrial servers with Intel^® Xeon^® processors with up to 40 cores. A large selection of multi-touch panels guarantees mature functionality and modern operating comfort on the machine. More than 100 signal types and 1,000 different EtherCAT terminals as well as decentralized I/Os serve the entire spectrum of sensors and actuators. TwinSAFE provides an integrated, standardized and modular safety concept. The drive technology product portfolio ranges from the compact drive amplifiers in terminal format to the high-performance high-end drives for highly dynamic servo applications.

Fast, open and ideally suited as a fieldbus for intralogistics: EtherCAT – the high-speed fieldbus

Efficient handling of large amounts of data, such as those generated by fully automated warehouse and distribution logistics, requires the efficient and structured acquisition, storage and use of these data. The high-performance data acquisition at machine and plant level, the so-called field level, is ensured by EtherCAT. With outstanding performance, flexible topology selection, extensive diagnostics and simple configuration, EtherCAT is ideal for use in intralogistics. EtherCAT communicates with 1,000 distributed I/Os in 30 µs, offering virtually unlimited network expansion and optimal vertical and horizontal integration via standard Ethernet and Internet technologies. In particular in the area of high-speed applications in material transport, significantly higher-performance systems can be realized by means of EtherCAT.

• communication with 12,000 digital I/Os devices in 350 µs
• communication with 200 analog I/Os (16-bit) in 50 µs, which corresponds to a 20 kHz sampling rate communication with 100 servo axes every 100 µs
• network expansion: almost unlimited (> 500 km)
• up to 65,535 devices

However, EtherCAT is not just about high performance; the control of costs is at least as important: EtherCAT uses low-cost Ethernet cables and supports flexible cabling topologies. In addition, EtherCAT devices do not require switches, special fieldbus cards or IP addresses. Another advantage: Existing network and fieldbus technologies as well as devices can be fully integrated into an EtherCAT-based system.

More than 6,000 companies worldwide (as of October 2020), which have joined forces to form the EtherCAT Technology Group, now support the technology developed by Beckhoff. Due to its widespread use around the world, a large number of EtherCAT-compatible devices, sensors and actuators are available on the market, ensuring a high level of investment security and guaranteeing a suitable solution for every problem. The openness and properties of EtherCAT processing "on the fly", high-precision synchronization, free choice of topology and integrated diagnostics meet the present-day and future requirements for modern warehouse and distribution logistics. This applies both to the planning and development of new plants and to the modernization of existing plants. Beckhoff offers numerous gateway solutions that enable older or third-party technologies to be integrated into the new EtherCAT world.

While EtherCAT with a communication speed of 100 Mbit/s meets the vast majority of current requirements, EtherCAT G and G10 are already available for the future with bandwidths of 1 Gbit/s and 10 Gbit/s respectively, which can be seamlessly integrated into the existing EtherCAT system. With increasing demands on industrial image processing, complex motion controllers, IoT functions, high-end measurements and the associated increasing volume of data, these technologies will become increasingly important in order to be able to realize trendsetting intralogistics systems.

EtherCAT P: 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 mechanical engineering – they have to be procured, configured, connected and – in the worst case – assembled. EtherCAT P significantly reduces this expenditure. It combines EtherCAT communication with the power supply for the connected consumers in a 4-wire standard Ethernet cable. In addition, EtherCAT P enables energy forwarding directly via the devices. The well-known advantages of EtherCAT are retained, such as free topology selection, high speed, optimal bandwidth utilization, high-precision synchronization, integration of safety functions and extensive diagnostics. This makes EtherCAT P the ideal bus system for sensors, actuators, drive and measurement technology in intralogistics systems.

The previously familiar switch boxes and control cabinets can thus be partly or completely dispensed with, so that complexity and costs as well as the footprint of the systems are reduced. Thanks to EtherCAT P, it is possible to implement modular machines and system concepts with high flexibility and considerably reduced installation and commissioning effort. Material costs, assembly and time are saved without loss of functionality, and the frequency of errors during installation is reduced.

TwinSAFE: the scalable safety solution in software and hardware

A feature of storage and retrieval systems, e.g., in high-bay warehouses, is the connection of numerous standard and safety I/Os, which may be combined with various drive technologies. The integrated safety solution from Beckhoff ensures continuous safety. In TwinSAFE, Beckhoff has implemented a universal safety concept that integrates safe functionalities into the standard control platform: from the PLC to the I/Os to the drive technology. All safety functions, such as emergency stop, safety door monitoring, two-hand operation, muting, safe position, safely limited speed, etc., are programmable or configurable with the TwinCAT uniform engineering platform. The safety technology is seamlessly integrated into the terminal segment via the TwinSAFE I/O modules in the protection classes IP 20 and IP 67; the safe signals can be mixed with the standard signals as desired.

With the aid of the TwinSAFE SC technology, it is possible to make use of standard signals for safety tasks in any network or fieldbus. Corresponding EtherCAT Terminals are available for the acquisition and secure transport of the signals via EtherCAT. The typical safety functions can be programmed and configured on the EL6900, EL6910 TwinSAFE Logic or the compact EK1960 safety controller, based on standard safety function blocks according to the safety requirements. The required safety functions can be executed centrally or decentrally in almost all TwinSAFE devices to support modular system concepts.

Advantage through TwinCAT Vision

One of the biggest challenges in the field of warehouse and distribution logistics is the sorting and further processing of different goods. Due to the different shapes, sizes and packaging materials, the detection and sorting of individual packages is very complex. The consequences of this are high costs and often slow and error-prone sorting procedures. With TwinCAT Vision, the PC-based control specialist Beckhoff offers a real-time image processing solution integrated into the TwinCAT world. Costly, time-consuming and error-prone sorting procedures are now a thing of the past.

The approach of PC-based control technology offers the ideal solution here: In addition to PLC, motion control, robotics, high-end measurement technology, IoT and HMI, TwinCAT Vision now also integrates image processing on a uniform control platform. This makes engineering much simpler, because the configuration or programming takes place in the familiar environment. At the same time, all control functions derived from the image processing can be synchronized in real time. Latencies are eliminated, and all image algorithms are executed in real time. This shows the enormous quality advantage over conventional vision solutions: with TwinCAT Vision, machine manufacturers can integrate all image processing tasks directly into the master controller. The result is modern machine concepts for intralogistics that meet future market requirements and increase competitiveness and investment security.

EtherCAT drives for highly dynamic positioning tasks

Warehouse and distribution logistics require a high degree of flexibility and scalability. Automated storage and retrieval systems, high sorting speed, robotics and handling for the transportation of crates and pallets as well as automated guided vehicle systems each place different demands on the control and drive technology. With an extensive drive technology portfolio in hardware and software, Beckhoff supports all drive technologies, from the control of simple and inexpensive three-phase asynchronous machines for less dynamic processes or simple adjustments to highly dynamic servo drives for portals and storage and retrieval machine solutions.

The scalable drive solutions from Beckhoff cover a broad range of applications: from the compact servo terminal and the AMP8000 distributed servo drive system to the AX8000 and AX5000 EtherCAT servo drives. The integrated, fast control technology of the AX series supports fast and dynamic positioning tasks. EtherCAT enables the connection of the drive technology to the PC-based controller and supports coupling to other communication systems. The AM8000 servomotor series is characterized by the One Cable Technology (OCT), in which power and feedback system are combined in a standard cable. In the lower performance range, the EtherCAT drive terminals are an inexpensive and compact alternative for conveying applications.

The AMP8000 distributed servo drive system, on the other hand, opens up new possibilities for modular machine concepts in intralogistics: The AMP8000 integrates the servo drive directly into the servomotor in a very compact design. By relocating the power electronics into the machine, the space requirement in the control cabinet is reduced to a single coupling module, which supplies several distributed servo drives with only one cable via a distribution module. A further expansion stage completely eliminates the control cabinet space required for the drive technology. Whereas the connection of the drives to the control cabinet is reduced to only one cable with the coupling modules, it is completely eliminated when using the AMP8620 power supply module. The result is significant savings in terms of material, installation space, costs and installation work.

Improved efficiency, communication and cabling for motor-driven roller conveyor systems

The EP7402 EtherCAT I/O Box is the optimal controller for conveyor systems in intralogistics, distribution centers and warehousing. The EP7402 offers two outputs with integrated motion controller for direct connection of 24 V DC roller motors or other BLDC motors (up to 3.5 A). For example, light barriers can be connected or communication between different modules can be realized without the central controller via eight additional digital inputs/outputs. The EP7402 takes over the complete control of the roller motor irrespective of the manufacturer of the conveyor or the motor. The motor control is sensorless. Maximum rated current, start-up or deceleration ramps as well as various other parameters can be configured, which allows optimal adaptation to different applications.

The EP7402 can also be operated without a PLC in pure conveying mode. It provides functions such as Zero Pressure Accumulation (ZPA) as well as single or block removal. Additional EtherCAT devices such as digital and analog I/Os, barcode readers or safety devices can be connected to the additional EtherCAT junction. The EtherCAT Box, which measures just 174 x 60 x 36.5 mm, can be mounted on the conveyor frame in any installation position in standard lateral profiles. It does not require any additional protective cover, which saves additional mounting space. Power supply and EtherCAT communication run through just one cable with a B23-ENP hybrid connector (28 A/45°C current carrying capacity).

Scalable and modularly expandable CX2000 Embedded PCs

With the CX2000 Embedded PC series, Beckhoff offers modular Industrial PCs for DIN rail mounting that are scalable in performance and enable the direct connection of Bus Terminals or EtherCAT Terminals. Depending on the performance requirements, the CX2000 series offers a choice between different basic CPU modules with Intel^® Celeron^®, Core™, Xeon^® or AMD Ryzen™ processors that can be combined and modularly extended with various power supply units, some with integrated UPS functionality, and other components of the CX2000 product family.

The operating system can be either a Windows-based operating system or alternatively use TwinCAT BSD, newly introduced by Beckhoff, in order to be able to react flexibly to the requirements of the intralogistics industry. TwinCAT/BSD is based on FreeBSD, an industry-proven and reliable Unix-compatible open source operating system.

The Embedded PCs were developed with a view to optimized interaction with EtherCAT. EtherCAT offers a wide range of application options. Due to the separate Gigabit-Ethernet interfaces, it is possible to use EtherCAT with cable redundancy by using one of the Ethernet interfaces as a redundancy port. In addition, devices with EtherCAT slave interface can be operated such that several intelligent controllers can be synchronized via an EtherCAT network.

TwinCAT: the universal engineering and control platform

As a universal automation software, TwinCAT bundles all direct control functions such as PLC, motion control, robotics and safety functions. In addition, tools are available for the operation of the machine, such as an HTML-based visualization system. Extensive tools are available for the integration of image processing, measurement technology or condition monitoring of plants, which improve the quality of processes and increase plant availability through predictive maintenance. All functions run as software modules on the PC. TwinCAT also supports a variety of established and new protocol standards. Together with the open interfaces of the PC, they guarantee the seamless integration of all system parts as well as communication with the material flow computer and the warehouse management system. Functions and protocols that are tipped to be the new standards for cloud-based systems in the Smart Connected Warehouse already exist in TwinCAT. The TwinCAT IoT product family combines a variety of software packages for sending collected or pre-processed data to higher-level systems, such as cloud services, via standardized interfaces and protocols such as OPC UA or MQTT.

IoT and Industrie 4.0 in the smart warehouse

Beckhoff provides the basis for the realization of IoT and Industrie 4.0 concepts in warehouse and distribution logistics with TwinCAT IoT, standardized interfaces and protocols such as OPC UA. In intelligent warehouses, all systems involved are continuously networked, from the control level to warehouse management and the retailer's e-commerce software. Regardless of their shape, size and weight, the products are automatically removed, packaged and shipped quickly and seamlessly, for example via a fulfillment center, in order to meet the tight lead times from the receipt of order to the delivery of the package. In addition to the classic tasks of control technology, vision applications, e.g., for determining the position and orientation of goods, can also be realized with TwinCAT. With TwinCAT Analytics, Condition Monitoring, Power Monitoring and the real-time TwinCAT Scope, tools are available that enable predictive maintenance, improved diagnostics and extensive remote maintenance options to increase uptime. These are decisive criteria for modern intralogistics environments that are heavily influenced by e-commerce requirements. TwinCAT Machine Learning is available for the autonomous optimization of plants, systems and robots via pre-trained neural networks. Integrated into the Beckhoff real-time automation platform, these tools ensure that intralogistics systems or centers can meet the growing demand of consumers for shorter delivery times with high adherence to delivery deadlines and can handle returns quickly. With TwinCAT and EtherCAT, Beckhoff is already a leader in the automation of intralogistics systems.