AutoID technology – quo vadis?

Automatic identification systems such as 1D/2D-code and RFID readers are tried-and-tested, indispensable technologies for controlling industrial production processes and logistics workflows in the supply chain. At the same time, Industry 4.0 and IIoT have put digitization at the focus of advancing automation. What demands will in future be placed on modern identification systems? Has the classic reader, which forwards a code via a serial interface to a control, become obsolete?

The classic bar code

The classic bar code as an optical identification system was introduced in the 1970s. In the meantime, various types of bar code are now in use worldwide (e.g. GS1-128, Data Matrix, QR Code, Aztec Code). The bar code – e.g. in the form of a printed label – has its simple usability, its extremely low cost and complete global standardization to thank for its significance as the world's most important identification medium. The bar code has become our daily, almost unnoticed companion in our personal environment – but also, of course, in industrial applications.

RFID

Radio frequency identification (RFID) operates in the radio frequency range and utilizes the electromagnetic interaction between mostly passive RFID data carriers (so-called tags) and an antenna generating the electromagnetic field. Initial practical applications came on the market at the end of the 1980s (e.g. the electronic vehicle immobilizer). The technology then became widespread in the early 2000s with the availability of new frequency ranges (HF and UHF) when contactless card systems were introduced and low-cost RFID labels, particularly in the retail market, opened up new possibilities for automated logistics processes.

Advantages of RFID over the bar code

The advantages of RFID compared to the bar code are obvious: Unlike the bar code, RFID requires no direct line-of-sight between the data carrier and reader. And another often important point: Additional data can be stored on the RFID data carrier so that as well as an individual code (the so-called unique ID or electronic product code (EPC)), each object can also be assigned additional, decentrally stored information about its properties, history or its current state.

After many years of targeted technical development and with extensive experience in different industrial sectors and applications in practically all industrial production processes and in the supply chain, RFID has developed into an established and reliable identification technology. Its advantages over the bar code play out wherever the application conditions and the cost-benefit calculation allow the use of RFID.

RFID versus bar code?

Today, both technologies live in peaceful coexistence, particularly in track-and-trace applications. For example in the automotive industry where production processes need to be continuously monitored while at the same time an eye must be kept on all material flows necessary for component supply. Linked to this are further state information about the condition of the machines and systems as well as the control of container loops and warehouse management. As "enabling technology", both laser-based or camera-based optical identification systems and RFID systems today make a major contribution to end-to-end automation and process tracking. And that's not all: They provide the basic data for a digital map of the production system, including all components involved and the logistics processes. At the same time, the evolution of classic production through to the "smart factory", logistics and "smart material flow", all of which was set in motion by Industry 4.0 and Industrial IoT, demands the adaptation of established AutoID systems to the enhanced requirements of digitally networked systems on the shop floor. The developments needed to achieve this extend to the functionality, communication capability and performance of AutoID systems.

Functionality

An important step toward the optimization of AutoID systems with respect to the digitization of production processes is condition monitoring. This requires the integration of sensors in the AutoID devices. These sensors enable condition monitoring of the reader and deliver cyclical information on the device state, warn of irregularities in the quality of the acquisition process and by means of downstream analyses allow prompt intervention or predictive maintenance of the system. The integration of external sensors in order to determine the current state at the same time as object identification and to link this to the object ID stored on the data carrier also provides a considerable benefit for the optimization of process transparency. Operating as an IO-Link master, an AutoID device can, for example, collect data from multiple IO-Link sensors installed at the reading location very easily and – either forward this data to a control system – or, with the appropriate hardware equipment, even preprocess it in the device itself using suitable software applications.

Communication skill

The communication capability of AutoID systems is of key importance because it is responsible for digital data exchange both at control level and with higher-level administrative and planning systems.

Typically, Ethernet-based fieldbus interfaces such as PROFINET or Ethernet/IP have long been used for the real-time capable control of processes. The necessity of combining process-related identification procedures with the monitoring of simultaneously determined operating and device states increases the demands on the communication interfaces of AutoID systems. In particular OPC UA as an open data exchange standard is now increasingly being used in the AutoID devices of many automation manufacturers. The interlinking of devices within a network on the one hand and communication with control and IT systems on the other via so-called OPC UA Companion Specifications is possible irrespective of the manufacturer. For AutoID systems in particular, the OPC UA AutoID Companion Specification that provides information models for the use of optical identification systems and RFID has existed since 2019.

The ability of AutoID systems to act as OPC UA servers allows all systems involved in the process, e.g. machines, robots, industrial trucks and storage systems, to be integrated interoperably in a uniform production and intralogistics system based on OPC UA. The material flow is controlled dynamically and flexibly based on the order data from the production plan and the most recent process data that is obtained from the identification process (the "read events") and the simultaneously acquired operating states.

Performance

As is generally known, the use of RFID systems in the UHF frequency range is subject to certain restrictions with respect to the frequency bands authorized in the regions and countries concerned. In this regard, especially incompatibility between EU rules and the regulations in the USA is an obstacle to cross-company use of RFID systems and therefore to complete networking and transparency of a supply chain. To eliminate this disadvantage, in 2018 the European Commission agreed to release a so-called "upper band" from 915 to 921 MHz in addition to the existing frequency band from 865 to 868 MHz. Besides the at least partial harmonization with the North American frequency range, the bandwidth of the transmission channels and the maximum permissible transmitting power were also improved allowing a significant increase in the usability of this technology, particularly in logistics processes.

A small drawback: In Germany and a few other European countries, the implementing decision of the EU has so far not been acted on due to national restrictions. Nevertheless, a positive development can be seen across the EU with regard to the functional usability of RFID systems.

With logistics processes in particular, large quantities of data often occur, e.g. if industrial trucks are used to transport goods and a pallet loaded with a large number of containers is detected as it passes through an RFID gate. These identification processes are used to automatically capture and book material movements, and therefore to create complete transparency with regard to order status and material availability. In order to provide a goods management system with only the essential and usable data sets, the use of suitable middleware systems on external servers and IPCs which filter, aggregate and evaluate the often large quantities of raw data from the RFID readers and forward it as business events via IT-compatible interfaces and communication protocols, have proven effective for RFID applications. The hardware performance of AutoID devices has already increased to such an extent that middleware or other software applications can be installed directly in the device, thus enabling direct communication with facility control systems as well as cloud communication e.g. via OPC UA or other network protocols such as MQTT.

Summary

The performance of AutoID systems is set to increase further and, thanks to modern network connectivity, it will be possible to utilize this performance to implement individual use cases. As a result, AutoID will in future also play an even more crucial role in the digitization and optimization of industrial production and intralogistics processes, also in combination with other technologies such as RTLS (UWB) or 5G and 6G. Future identification systems are intelligent, interoperable controllers that support modern, internet-capable communication protocols, capture and evaluate sensory data and make it available to many clients in a network. The installation of customer-specific apps in the device allows adaptation to individual use cases and thus offers additional potential for the optimization of industrial processes.