Technology report: RFID or bar code? – Has there been a changing of the guard in the identification solutions used in automation?
Two identification technologies – RFID and bar code – are competing for the favor of users: With the promise of making a decisive contribution to realizing an automated transparent production and supply chain to meet the requirements of Industry 4.0. But which technology is the right one today? Has the bar code outlived its purpose? This article takes stock of the current situation with respect to modern identification technologies and casts a critical eye over each of them.
Do you still remember the time nearly 20 years ago? When there was an atmosphere of positivity and RFID technology was enjoying a boom? RFID (Radio Frequency Identification) is not really a new technology. The physics behind it was developed back in the early 20th century. The first systems and product solutions for industrial applications were already available in the 1980s – mostly as proprietary solutions in the low frequency (LF) range (125 kHz). Typical applications from this time, such as animal identification, electronic vehicle immobilizers and vehicle identification, are still used today and have become well established.
The classic, tried-and-tested bar code has been in use since the 1970s. At that time it was a technology that was met with some controversy! Today it is hard to believe that the unique identification of a product using a printed bar code caused discussions regarding continuous surveillance and data protection. In the meantime, the bar code is used everywhere. A world without bar code labeling on products – in the consumer sector or on parcels at a time where the volume of goods traded online has mushroomed – is now simply unimaginable.
The enormous significance of the bar code as by far the most important identification medium is down to its simple applicability. For example, as a printed label, due to its extremely low cost and, last but not least, because of its universal worldwide standardization. The bar code, which is now available in various forms (e.g. Data Matrix, QR code), has become an inconspicuous companion in our daily lives and also in industrial applications. And an end to its continued development is not in sight. But the bar code does have its limits: To be read, it requires a direct line-of-sight. And, once the bar code is printed, the data content (encoded information) can no longer be changed.
This is where RFID comes into its own: This technology was intended to do everything the bar code can, but much better, and through various other convincing benefits slowly but surely oust the bar code. Targeted initiatives by industrial corporations that attempted to optimize their processes by using RFID, especially in the supply chain, as well as by technology providers that propagated the use of RFID in almost all application areas, triggered the so-called RFID hype at the beginning of this century. The impression arose that RFID was a cure-all for every identification task and would, in the medium term, replace the bar code. In retrospect, it must be stated that this prediction that was voiced many times publicly was destined to be proven wrong because it was based on extremely little practical experience and the physical limits of the technology were underestimated.
After many years of targeted technical improvement and with extensive experience from countless pilot projects in different industries and applications, RFID developed into an established, reliable identification technology which can leverage its advantages over the bar code, provided that the application conditions have been carefully examined and a serious cost-benefit calculation has been made.
In the meantime, the behavior of RFID under different ambient conditions is well known. Modern UHF systems (860-960 MHz), for example, can be optimized for almost any application through increased sensitivity and extensive configuration options. As a result, the use of RFID in many industrial sectors, e.g. for track&trace applications in the automotive industry, completeness monitoring in production processes or for monitoring container cycles in logistics, has proved to be a powerful and reliable technology many times over and has established itself as the de facto standard for identification tasks. And yet the bar code is and remains the top performer in all industries. Its potential applications are near unlimited. In many cases, there is simply no need for the specific benefits of RFID.
Moreover, in the segment for 1D/2D scanners, smart cameras and vision systems, the market now offers extremely effective products that are tailor-made for many applications in industrial sectors. Equipped with modern communication interfaces such as Ethernet-based fieldbuses or OPC UA and therefore optimally prepared for today's future requirements of Industry 4.0 and for network and cloud capability necessary for the Industrial Internet of Things.
There has not been a changing of the guard. The world of identification technologies continues to be characterized by a peaceful coexistence between two physically very different systems which each have their own merits and even perfectly complement each other in many applications. The bar code claims to be the only identification medium that is universally usable and accepted across the globe and whose technology is highly standardized and has proved to be extremely reliable.
The following typical areas remain the domain of RFID: challenging surroundings (e.g. harsh environmental conditions with a high degree of contamination), the detection of many data carriers simultaneously in a group or the repeated reprogramming of RFID tags in returnable systems in a closed logistical cycle. So long as an RFID tag has an electronic circuit, consisting of a metallic antenna structure and a silicon microchip, the bar code will always score the point for the technology with the lower manufacturing cost. Especially in high-volume applications with single-use data carriers, the use of RFID tags is often extremely difficult to justify from a cost perspective
It should be mentioned that the sustainability of RFID tags is also a hot topic and must be taken into consideration when deciding which technology to use. The RFID tags produced using valuable raw materials are subject to the same recycling regulations as other electronic components and assemblies. The question as to whether RFID or the bar code is to be used is not a black-and-white matter. Today we find ourselves in the fortunate situation of being able to choose the technology that is best suited to the specific application. Both systems have achieved the technological maturity required to allow this. It is our responsibility to make the right decision based on professional advice and careful analysis.