Automatic identification technology or Auto ID is a method of identifying objects, collecting information about the object and capturing that information directly onto a computer system with little to no human involvement. Auto ID technology helps to reduce human effort (and thus error) and also to keep information up-to-date quickly and easily.
What is RFID technology?
Radio Frequency Identification (RFID) is an automatic identification technology where signals or radio frequencies emitted from tags or identifiers are used to track or identify specific assets. RFID is a popular choice and is able to integrate with a variety of applications. RFID can broadly be divided into three groups, Low Frequency (LF), High Frequency (HF) and Ultra High Frequency (UHF).
The Low Frequency RFID band is between 30kHz and 300kHz. Despite this bands short read-range and slow data transfer speeds, low frequency waves can pass through liquids making it ideal for livestock identification applications.
High Frequency RFID is used by the NFC (Near-Field Communication) protocol and tap-to-pay applications. HF typically works at 13.56MHz and at this frequency reliable communication is limited to less than 20cm. The limited range also provides better tag reading control.
UHF RFID mostly operate between 860-960MHz. In South Africa the permitted ranges are 915.4-919MHz and 865-868MHz. At these frequencies the working range can be 3-10m for passive tags or up to 50m for active tags. The longer range of UHF systems and faster data transfer speeds has made it ideal for multiple tracking applications across the world.
How does RFID work?
UHF RFID allows wireless transfer of information between a tag and a reader with RF waves acting as the transfer medium. To make the information transfer happen RFID readers/interrogators prompt the antennas to transmit RF waves at the correct frequency and intensity. Antennas then listen for any returning RF signals. If a UHF tag is within range (usually 0-10m) it will send RF signals that is then detected by the antenna(s) and relayed to the reader. The tag information captured by the reader can then be distributed over a network connection.
Tags allow a digital identifier to be assigned to virtually any discreet object. Most tags also have the ability to store custom information, allowing data to travel with an asset. The most commonly implemented RFID systems use passive tags. Passive tags are dormant and only emit a signal once they have absorbed enough electromagnetic energy to activate the imbedded chip and transmit signals back to the antenna.
To activate passive tags, an antenna emits electromagnetic waves and then listens for any responses from tags to relay to the reader. Antennas come in various forms and degrees of toughness. The tag read and write performance depends largely on the antenna used. The foremost difference in antennas, that effect performance, is whether the antenna is circularly polarised or linearly polarised. When linearly polarised, the tag reading distance is greater but the tag vs antenna orientation must be consistent. Circularly polarised antennas sacrifice a small amount of reading distance but can read tags in multiple orientations.
The RFID system is controlled and operated largely through the reader (sometimes referred to as an interrogator). This device modulates and powers the antenna and is responsible for network communications. It is also through the reader that commands can be relayed to tags, like writing new information to the tag memory or silencing a tag that has already been read.
Networking & interface
The software that receives, interprets and presents the RFID information is what enables organisations to benefit from the information collected. Once information is received from the reader, it must be processed for use by software and be delivered to an interface. This interface represents the intended destination and reporting platform of the RFID tag data and can take many forms like databases, graphical user interfaces, computers, servers, dashboards, programmes etc.
Integrated Readers and Antennas
Because of the central role the reader plays in a working RFID system, integrated Reader and Antenna configurations are available. Integrated readers simplify installation but can potentially limit the scalability of the system in future. Similarly, many RFID installations require the construction of portals. Portals are often needed at doorways and conveyor belts so pre-fabricated portals are available for these applications and others. This greatly simplifies installation as these portals are already configured with the optimal antenna/reader combination. It may be tricky to find a portal with the correct dimensions but a suitable modular item is much easier to install, especially when aesthetics is important.
Many applications require tag information to be accessible at the point where tags are scanned. Handheld or mobile RFID scanning devices are ideal for scanning and collecting tag data over a distributed area. These devices are capable of handling the entire RFID information chain independently, while also running a customised interface or app. Like most mobile devices, connectivity is available in various forms (Wi-Fi, 4G, Bluetooth) allowing the device to share the data collected whenever it needs to.
Why use RFID?
While RFID is not the only automatic identification technology available it does provide unique benefits that have made it a popular choice across the world. Benefits of using this kind of technology include:
Easy to read and attach – RF waves can travel through a number of materials, allowing tags to be read even when placed inside containers or out of view (no line of site needed).
User memory – Apart from providing a unique identifier, RFID tags also have memory that can be used to log events or store a status, allowing data to travel with an object.
Survivability – RFID tags can get wet, soiled, crumpled, painted over or be subjected to high temperatures and still function as an identifier.
Wireless detection – An RFID system reads tags from a distance allowing integration with minimal hindrance to existing processes.
In order to create the ideal solution for a company, a needs analysis has to be established which allows specialist providers like Osiris Technical Systems to identify the appropriate solution needed. It would also determine how intelligent and integrated the final system has to be. This information is important for designing the overall RFID system and ensures that hardware and software capabilities are compatible with each other and able to deliver the solution envisioned.