UHF RFID – the radio technology of choice for Industry 4.0
First of all, the manufactured products, representing the most important objects within the factory, must become smart. This enables us to query these products at every stage of the product lifecycle (PLC). For instance, it would be possible to query the objects identity, health or status, to name just a few. Smart objects will be able to respond to queries like these.
We all know the term smart from the telecommunications sector. In the business world, it will be hard to find a person without a smartphone, including most readers of this document. Why do we call these devices smart?
Its because they are multi-functional, enabling us to translate our interests into action and to reach our goals which are quite individual, by the way. One user wants to communicate, using an email app for this purpose. Another user will use a weather app in order to obtain the latest forecast. When we are traveling, a map application and maybe a travel guide from an eBook app may be helpful. In the past, all kinds of different media and technical equipment were required for these tasks. Today, the smartphone in our hands can fulfill these functions thanks to its smartness. (This also raises the interesting question whether we thus have a Turing machine in our hands)
However, an essential prerequisite must be met for this, and well discuss this later in this article. This prerequisite is known as the infrastructure. How many smartphones would Samsung and Apple sell without the existing GSM/UMTS infrastructure and without the data networks offering enormous bandwidths? How smart would our technology be without this prerequisite? It is also important that this technology is wireless.
So whats the link between the smartphones and the smart objects needed to further advance our value chains?
Our industry has reached a stage in which we are assigning names to the products. During production, identification technologies including bar codes or matrix codes are used to address specific PCBs and to control the manufacturing process. These approaches have helped to solve many problems and to increase the efficiency of our manufacturing and logistics processes.
Nonetheless, more and more users are reaching the limits of these technologies. For instance, optical identification technologies require a line of sight. Due to their read-only nature, they also rule out the storage of any additional data on the object, i. e. on the product. In a real-world scenario, an optical code would be attached to the PCB representing the main functionality and the backbone of any electronic product.
As soon as a protective coating is applied to the PCB or the board is potted, the code becomes inaccessible, mandating the transfer of its information content to a different medium. Thus, another code must be attached to the case. This step is necessary once again when the device is packed and must be repeated with each new packing layer.
We therefore have reached the limits of Industry 3.0, and a new technology must be employed for the further migration towards Industry 4.0. Based on the previous discussion concerning the smartphone, it is advisable to use a wireless technology.
This technology is readily available and has reached a level of maturity enabling its large-scale use in the industry. It is called RFID, for Radio Frequency Identification and replaces bar codes and dot matrix codes (DMCs) with so-called tags. These devices include memory partitioned into a pre-programmed, unique serial number, a writable serial number memory for a custom number range and a user memory for storing additional data.
It is a crucial feature that data transfers are now done by radio and data can be read and written. It is thus possible to add data to a product during its lifecycle and to read these data off-line. Therefore, no connection to a database is required in order to obtain any relevant information. The object itself is turned into an information carrier. Additional value can be generated based on these data during the entire PLC.
The smart PCB thus becomes the backbone of the entire PLC. The transparency lost by outsourcing processes is restored using a unified technology. Instead of being just theoretical, the mentioned use cases are based on real-world scenarios in different industries where RFID technology is already used successfully. For instance, RFID-based process control and monitoring is a standard procedure in many fields including the fashion and textile industry, the paper processing industry and the steel and automotive industry.
Surprisingly, the electronics industry is still becoming aware of this issue even though its adoption is taking up speed dramatically. Some use cases have already been documented in the trade press, including Cisco (production at the Chinese EMS Jabil) and Schneider Electric with its own manufacturing site in Carros in Southern France. Lacking awareness of UHF RFID-based solutions is the primary factor responsible for the slow adoption of this technology in the electronics industry. The RFID Value Creator consortium is among the institutions trying to educate the industry.
Figure 1: Use of Muratas Magicstrap RFID tag in electronics production.
Thanks to products like Muratas Magicstrap, the technical implementation is not a problem anymore. This product provides all the capabilities required for migrating towards Industry 4.0. As a standard SMD component, Muratas UHF RFID module can be mounted on a PCB using established pick-and-place processes. The PCB thus becomes a RFID tag and can be used as a smart object. For applications requiring traceability starting at the PCB manufacturing stage, a low-cost embedding process was developed with Beta LAYOUT. This approach is available at Schmoll Maschinen as an automated process for every PCB manufacturer or can be implemented as an outsourced process step at Beta LAYOUTs RFID Service Center. The component is integrated into the circuit using a simple copy-and-paste step during the development process. Using the Magicstraps integrated front-end circuit, an existing metallization (i. e. the ground plane) can serve as an antenna.
Figure 2: RFID readers underneath conveyor belt in PCB manufacturing line.
Therefore, no special antenna design is required. Instead, it is only necessary to reserve sufficient space for the SMD device measuring just 3.2mm x 1.6mm. Depending on the individual conditions, a transmission range of several meters can be achieved even through the device housing and external packaging. As mentioned earlier, this does not require the device to be powered up. Instead, sufficient energy is extracted from the field emitted by the read-write device corresponding to the scanner used in bar-code systems.
Therefore, this can be considered an energy harvesting system. Looking into the future, it should be noted that a new product variant offering a digital interface will enable a serial communication with the MCU or CPU. RFID will thus become a low-cost wireless alternative to Bluetooth or ZigBee.
Figure 3: Magicstrap RFID tag on PCB.
Value creation is a highly fragmented process in the electronics industry. As a result of the outsourcing efforts in recent years, different phases of the PLC take place at different companies. Therefore, it is very important that these players join a cost-sharing discussion.
Quite often, OEMs will draw the major benefit from using RFID technology, while contractors and partner companies must pay for the creation of the infrastructure. We invite all parties to join a fair discussion. Existing RFID implementations clearly demonstrate that all parties will eventually benefit from taking steps towards each other.
A UHF RFID-based Industry 4.0 concept will therefore also contribute to solve the problems resulting from the fragmentation process. The author invites everybody to join the RFID value creators and to participate in the active implementation of a wireless-based Industry 4.0 to the benefit of all players.
About the author:
Alexander M. Schmoldt is RFID Business Development Manager Europe at Murata Management B.V. — www.murata.eu
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