The Bihl+Wiedemann Difference in AS-i Systems

Bihl + Wiedemann

Bihl+Wiedemann is a medium-sized company founded in Mannheim in 1992 by Jochen Bihl and Bernhard Wiedemann. It develops and manufactures complete automation systems for functional safety and data communication within plants and machinery. Its products are used worldwide across numerous sectors by leading manufacturers of consumer and capital goods.

Bihl+Wiedemann is a leader in automation and safety technology based on AS-Interface (AS-i). Its AS-i system was the first to be certified in 1995 by AS-International, an organisation with 300 national and international partners. The company also played a pioneering role in AS-i 5 devices introduced in 2019. This latest AS-i generation enables larger volumes of data to be transmitted at higher speed. Since 2019, for example, AS-i 5 modules have allowed a wide range of IO-Link devices to be connected simply and conveniently; since 2020 they have also enabled cost-effective solutions for complex drive-technology requirements.

Bihl + Wiedemann is among the leading functional-safety providers with AS-i Safety at Work, which it has supplied for nearly 15 years. Bihl+Wiedemann introduced AS-i 5 safety devices for the first time in 2022, enabling numerous safe and non-safe signals to be used under a single AS-i address.

The AS-i product portfolio includes masters/gateways, AS-Interface modules, safety components, bus couplers/master simulators and software developed in-house.

AS-i 3 and AS-i 5: The Ideal Combination for Modern Drive Technology

Automated material-flow lines for modern material-handling systems in logistics centres or complex manufacturing environments often extend for several kilometres. Along these lines are sensors, switches, measuring devices, scanners, drives, control panels and safety systems of every kind. Large areas and many devices must accommodate standard and safety signals as well as both simple and complex tasks—ideally combined within a single application. This is precisely the environment for which AS-Interface wiring technology was created, and the interoperable AS-i 5 and AS-i 3 solutions provide an effective combination for every type of requirement.

All network participants connect power and communication through a single yellow profile cable; piercing technology provides simple, reverse-polarity-protected wiring; no plugs or preassembled cables are required; no special connection method or dedicated switch is needed; and safety is built in. No other wiring technology enables both individual components and large quantities of devices to be integrated into material-handling systems so cost-effectively and efficiently. Storage and material-flow technology, conveying and sorting equipment, shuttle pallet-storage systems, picking systems, stacker cranes and other crane technologies can all be connected to AS-Interface with ease. The established and widely used AS-i 3 standard excels at collecting digital I/O signals and implementing functional and passive safety technology, while AS-i 5 provides the transmission speed and data bandwidth required for more complex material-flow applications. The ability to integrate intelligent sensors through IO-Link and support Industry 4.0 communication through OPC UA also delivers a high degree of future readiness.

As a complete AS-i provider, Bihl+Wiedemann offers a portfolio that delivers flexibility and multiple design options for material handling. It accommodates the requirements of different drive concepts and manufacturers, while the fine-grained structure of the available modules and compatibility with both AS-i 3 and AS-i 5 support precisely tailored solutions—from one binary signal at a light barrier to the large, rapidly transmitted data volumes generated by scanners, RFID readers or encoders.

The versatility of the Bihl+Wiedemann portfolio is evident, for example, in the electric drive technology used in automated material-flow systems. AC motors with frequency inverters from companies such as Lenze, SEW-EURODRIVE and NORD DRIVESYSTEMS are standard drive solutions in many conveying systems. In the simplest case, they can be operated in binary form using AS-i 3 components. Less complex functions such as start/stop, run left or on/off can be implemented economically with cost-effective modules; adapting the pin configuration to the relevant drives also enables plug-and-play solutions.

AC motors with frequency inverters—where the controller can access performance parameters such as speed or acceleration and braking behaviour—can now be controlled efficiently using AS-i 5.  Bihl+Wiedemann motor modules provide CANopen, RS485, Modbus TCP and IO-Link interfaces while also supporting compatibility with several fieldbus interfaces. Speeds or defined acceleration and deceleration profiles, known as ramps, can be activated and changed cyclically and continuously. Conveying speed can therefore be adapted to both the object and the conveying line to provide gentle deceleration and acceleration—for example, where an object with a high centre of gravity could tip, or where conveyed material enters and exits a curved section, machine or crane. This serial control method also supports extended diagnostics: the yellow AS-i cable can transmit detailed status messages and information such as current power consumption and temperature from the frequency inverter to the AS-i 5/AS-i 5 fieldbus gateway.

Finally, Bihl+Wiedemann AS-i 5 modules with an integrated IO-Link master allow devices such as intelligent actuators—meaning smart drives with IO-Link—to connect easily to the system controller through AS-i 5. The precise scalability of modules with one, two, four or eight IO-Link master ports helps reduce costs, because users invest only in the IO-Link ports they actually need. This level of technical and economic efficiency is generally not possible with conventional IO-Link fieldbus modules, which are commonly equipped with eight IO-Link master ports and a separate Ethernet interface.

Implementing AS-Interface

As a wiring technology, AS-Interface can exploit all its strengths when used in drive applications. The Bihl+Wiedemann AS-i 3 and AS-i 5 portfolio combines the performance capability of fieldbus technologies with straightforward field-device wiring. The company's software packages with an integrated hardware catalogue enable simple, error-free engineering and commissioning of AS-i networks, as well as efficient addressing and parameterisation of AS-i modules in the field. If several frequency inverters in a system use the same parameters, values need to be stored only once and can then be copied to every other device. Moreover, unlike PROFINET, only one IP address and one web server are required to control up to 124 frequency inverters or 248 roller drives. For on-site device addressing in a material-handling application, the new AS-i 5/AS-i 3 Address Programming Device provides valuable support by assigning bus-device addresses quickly and easily without requiring an actual bus structure to be created.  Another widely appreciated function in the Bihl+Wiedemann software package is online bus information. This allows users to address devices, parameterise them live, and monitor inputs and outputs directly from a computer. They can immediately see the actual effect of new settings on the correct operation of the material-handling system and optimise them without delay when necessary.

Easy installation, high functionality and flexibility, low cost—and substantial user convenience: AS-Interface has established itself as an internationally standardised wiring system for modern conveying and material-flow technology.