The primary goal of the fourth industrial revolution is to optimize production processes, to minimize downtimes and to achieve an even more flexible production. The basic requirement is a sufficiently large data base containing extensive information concerning the production plant and the production process. Contrary to the greenfield method, a more theoretical image of an ideal factory network, the brownfield approach looks at reality, specifically how to make existing plants and factories suitable for i4.0. Here, AS-Interface offers decisive advantages.
A production hall somewhere in the world: a collection of different machines, technologies and interfaces. Over the years or even decades, everything was connected by a network of cables, pipelines and tubes. Production is running, and obvious production bottlenecks where recognized and fixed. However, now more information about the production is needed:

• How much energy is required per produced unit?

• What are the CO2 emissions during production?

• To what extent are the production machines utilized?

• What is the OEE of my production plant?

• How can processes be further optimized to achieve better product quality?

• How can maintenance intervals be optimized?

• How can downtimes be minimized?

IO-Link – the key to Industry 4.0

The list of possible questions is extensive. However, in general, an additional number of data sources, i.e. sensors, is needed to collect all necessary machine and production data. If these sensors are able to communicate, all the better. This is where IO-Link comes into play because it provides readable process information instead of unscaled analog data. For example, 6.3 mA becomes 150 mbar or 57° C. In addition, the IO-Link sensor is not only limited to a single processor value but can supply several process values, depending on the type of sensor.

AS-Interface – economical and easy  

But how can this sensor technology be implemented in the machines with minimal effort and without negatively affecting the production process? Ideally, the sensors would wirelessly transmit their data to the server. Unfortunately, the topic of providing energy to sensors is not entirely solved yet: Sensors need a power supply. However, since two line are needed to supply the sensors with power, why not use these lines to communicate with the sensors? Welcome in the world of AS-Interface.

AS-Interface impresses with its simplicity. A reverse polarity protected, two-conductor flat cable enables foolproof mounting of I/O modules into the system by using piercing technology. The piercing contacts of the I/O module pierce the flat cable to access the conductors. The I/O module is now connected to the ASi system, receives power and is able to communicate with the ASi master. A wide variety of different I/O modules ensures that almost any sensor signal can be processed, whether a digital switching signal, an analog value, or IO-Link data. The ASi flat cable has the impressive range of 600 m, and the user can freely choose the topology of the system. Larger distances of up to 3.2 km can be arranged through an optional fiber optics repeater. Whether flat cable or fiber optics, the system’s immunity to inference is unparalleled.

Intelligent ASi masters cyclically read the sensor information and can transmit all values of connected I/O modules via various interfaces and protocols, including i4.0-specific protocols like OPC-UA and REST-API. A targeted data preprocessing inside the ASi master is possible to reduce unnecessary large amounts of data, even in real-time applications like counters. Therefore, AS-Interface is technically and economically the perfect solution to retrofit sensor technology in existing production plants, creating a predictable and controllable brownfield project.

The system extends functionality and reduces costs.

This results in externally controlled linear drives in processing plants that propel digitalization. Reducing machine downtimes and making better use of capacities: In intelligent process automation, plant operators take a holistic approach to the control levels as well as to innovative components and fittings on the field level. In this context, the valve specialist GEMU offers high-quality valve control systems with AS-Interface which support a successful automation.

Valve actuation as system-oriented solution

The GEMU combi switchbox 4242, suited for mounting on pneumatically operated linear drives, follows the trend towards decentralized plant intelligence. The valve stem position is reliably detected electronically by a backlash-free and force-locked adaptation – including evaluation. Integrated pilot valves allow direct control of the connected process valve. Intelligent microprocessor-controlled functions facilitate commissioning and support operation. The current position of the valve is indicated using far-reaching LEDs and reported back via electronic signals. Compared to external versions for larger installation spaces, this solution offers functional as well as cost-related advantages like fast response times or reduced compressed air consumption.

System-oriented functionality requires appropriate data transfer

Plant operators prefer safe bus systems like AS-Interface. As production processes become more automized, safe, fast, and economic connection options are of particular importance. From GEMU’s point of view, one of the most important advantages of AS-Interface is the master’s ability to address and reply to up to 62 slaves (actuators/sensors) via a single port. Another crucial aspect is the easy wiring that significantly reduces errors. The following AS-Interface profiles are available: 24 V, AS-Interface or DeviceNet versions as well as a version with an IO-Link interface.

Especially because the connection system is established in different areas of process automation and thus guarantees functional safety in process automation, the combination of a component, like for instance the combi switchbox, and AS-Interface implements the customer-specific requirements on the automation concept, and therefore complies with the need for more digitalization and networking.

More information: www.gemu-group.com

Functional safely, including human errors when connecting ASi, are the stories told by Prof. Tilo Heimbold and his team. As enthusiastic as Friedrich Schiller was about the connection between a handcrafted bell casting and the human life, the testing lab of the HTWK Leipzig shows its passion to test connections to the AS-Interface system. As of today, about 2,500 test runs and inspections of connectable components such as power supplies, masters, slaves, system ASICs, repeaters and ground fault detectors were performed, ensuring the system’s functional safety from the user’s perspective. In addition to inspections and tests related to the development project, the examinations of all electronic ASi components attached to the bus as the basis of a certification through the AS-International Association is planned to start in 2020.    

ASi-5 tested and deemed fit for usage

By now, the testing lab and the team of Prof. Tilo Heimbold are positioned as the development partner of AS-Interface. Inspection and test data, for example on measurement parameters like bus impedance, symmetry to ground potential, and EMC tests (BURST behavior) with error rate measurement, are valuable results for new developments such as the ASi-5 system and are incorporated into the its implementation.  The spectrum extends up to a complete inspection of all bus-related physical and logical characteristics according to the requirements of the system specification and IEC/EN62026-2. The focus is on the system’s ASIC as main component of slaves, repeaters and the manufacture-dependent masters.

Higher data throughput with AS-Interface

In the times of digitalization, the request for more data communications is raising, and the classic ASi system needed new functions for future-proof topologies with cloud structure. In cooperation with the HTWK Leipzig’s testing lab, a point-to-multiple-points multiple-step concept had to be developed that retained AS-Interface’s commonly known advantage in a master-slave topology. In developing AS-5 by changing the data transmission procedure, the Industrial Internet of Things’ (IIoT) potentials that promise extensive diagnostics including additional field data as well as faster system cycles are taken into account. Even though currently, many sensors and actuators operate on a relatively small data width, AS-Interface’s new upgrade keeps network costs for setup and components low without losing flexibility and modularity at any point.

ASi’s upward and downward compatibility

From the user’s point of view, it is important to ensure in the test lab that if both ASi-3 and ASi-5 components are included in one topology, I/O data communications are guaranteed. The absolute continuity of ASi components – for either upwards or downwards compatibility – is always maintained at the sensor/actuator level. The absolute zero-error transparency, proven by HTWK through various test setups, is decisive for a reliable data transmission. In the lab, measurements on four identified worst-case topologies guarantee functionality of typical, critical system topologies of sensors and actuators connected to the master.
At the same time, meticulous function tests opened up the data-technological advantages of ASi-5 to the lab’s specialists. Different from ASi-3, the system management with error diagnostics now also runs parallel to I/O data communications. When adding I/O-Link as a slave, condition monitoring functions become available. Through the performance gain when adding the new chip, AS-Interface becomes an IIoT data feeder at the lowest level of automation – exactly where increasing requests for decentral intelligence in plants and machines are directed.

All in all…

…  functional safety in industrial communications in existing plants can be seen as a retro process, to be permanently optimized and designed to be more efficient through digitalization. Data management and the associated industrial communications in automation is subject to constant change – either analog or digital. AS-Interface supports the users’ need in terms of real-time communications, linking to IO-Link devices, or the easy and cost-effective interconnection and wiring of sensors and actuators. HTWK’s testing lab puts everything to the test to guarantee functional safety of classic as well as cloud-based topologies with ASi-3 and/or ASi-5.

The cancellation of the Hannover Fair due to the Corona Pandemic was not known at the time of going to press. Please ignore the information about the July date in the magazine.

In principle, all improvements of the system are based on these changes. Not only more complex devices can be addressed, but also the diagnosis of the system and many mores has been significantly improved.

Learn more in the current German video youtu.be/1hcRt3Zx0m4.

Dongguan Hugu is a leading company in automation business with a focus on connection and data transmission.

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