Specifying and Using RFID for IIoT Asset Tracking
Contributed By Digi-Key's North American Editors
Asset tracking and supply chain management are important activities across a range of Industrial Internet of Things (IIoT) applications, including manufacturing plants, logistics and distribution centers, data centers, hospitals and health care, agricultural, construction, and transportation. Specifying a passive radio frequency identification (RFID) asset tracking system is complex. Valuable assets can be exposed to various uncontrolled conditions, including shock and vibration, hot, freezing cold, and wet environments during transport and storage, and there are various application-specific RFID standards to be considered.
Designers need rugged and reliable tags that withstand the harsh conditions of industrial, construction, and manufacturing environments which are available in various standard sizes and read ranges to suit the needs of specific asset types and classes. This article briefly reviews passive RFID technology and several industry standards related to RFID tags and data. It then presents RFID tags, readers, and system solutions from Molex, Murata Electronics, and ThingMagic.
A passive RFID tag consists of an antenna and an integrated circuit that includes an analog front-end (F/E) with a modulator, demodulator, RF energy harvesting unit, a controller with a coder/decoder, control electronics, clock, and memory (Figure 1). Passive RFID tags do not use batteries. In most passive RFID tags, the memory can be re-written, and RFID tags can exchange much larger quantities of data than alternatives such as barcodes.
Figure 1: A passive RFID tag consists of an antenna and an IC that includes an analog front end (F/E), controller, and memory. (Image source: Murata)
Passive ultra-high frequency (UHF) RFID tags can be read at distances up to several meters, and multiple tags can be read at once. In contrast with barcodes, RFID uses wireless communications, and tags can be read from outside of packing boxes without opening the box (Figure 2). In addition, RFID tags are insensitive to dirt, moisture, vibration, and other environmental factors that can interfere with the use of barcodes. RFID tags come in a variety of formats designed for specific applications. Some tags are designed for tracing and tracking metal items and use the metal surface as a booster antenna to increase the operating range. Various communication and data format standards have been developed for passive RFID tags.
Figure 2: RFID tags can be read at distances up to several meters. In some designs, multiple tags can be read simultaneously, and the tags can be read through boxes and other packaging. (Image source: Murata)
The RAIN RFID alliance promotes using the ISO/IEC 18000-63 GS1 UHF Gen2 protocol. RAIN (RAdio frequency IdentificatioN) is designed to link UHF RFID tags and the cloud. It enables RFID data to be stored, managed, and shared using the Internet. A system utilizing a RAIN solution has an RFID tag, reader, and software that can provide a link to the local network and from there to the cloud (Figure 3). The RAIN alliance has built on the ISO numbering system to simplify encoding using company identification numbers (CINs). The ISO-based numbering system is designed to support RAIN RFID tags’ collision-free identification. It is intended to provide an interference-free alternative to existing proprietary or vendor-defined data formats.
Figure 3: RAIN RFID is regulated by a single global standard called EPC UHF Gen2v2 or ISO/IEC 18000-63. (Image source: RAIN Alliance)
Electronic product codes and RFID
The electronic product code (EPC) Gen 2v2 used by RAIN is an air-interface protocol standard for passive UHF RFID tags. EPC Gen 2v2 includes features to improve security, deter counterfeiting and enhance privacy by enabling authentication of tags and readers. The memory of a Gen 2v2 tag can be partitioned into multiple files, and compliant tags can be used for electronic article surveillance (EAS).
The EPC standard was developed by EPCglobal and approved and adopted as the ISO 18000-6C standard. In addition to setting a standard for how tags and readers communicate, a suite of standards associated with EPC establishes how EPC data is shared among various users. An EPC is a universal identifier for physical objects. Since it’s widely used in RFID tags, the EPC tag data standard includes requirements for data in addition to the EPC that may be stored on a Gen 2 RFID tag. While there is a significant overlap between EPCs and RFID tags, they are inherently different; RFID is the data carrier technology, and EPC is an identifier and data format.
EAS and UDI regulations for medical devices
Similar to EPCs, Unique Device Identification (UDI) regulations in many countries require medical equipment to have individual identifiers to support EAS for the safe use and storage of medical equipment. UDI systems apply to many types of medical equipment but are especially important with surgical instruments where there is a significant risk of preparing incorrect instruments for a procedure.
Hundreds of different surgical instruments and inexperienced personnel can easily select incorrect instruments. The use of UDI and RFID tags can eliminate that concern. The use of RFID tags also facilitates the collection of the history of uses of individual instruments and the number of uses within a healthcare facility.
Passive RFID tag for surgical instruments and industrial tools
RFID system designers can use the LXTBKZMCMG-010, a small on-metal UHF RAIN RFID tag from Murata, for tracking surgical instruments, industrial tools, and similar metal objects (Figure 4). The LXTBKZMCMG-010 uses the metal surface to increase the read range as a booster antenna. This tag measures 6.0 x 2.0 x 2.3 millimeters (mm), operates over the entire UHF band, and has an operating temperature range of -40 to +85 degrees Celsius (°C), making it suitable for tracing and tracking metal objects in industrial environments as well as healthcare facilities.
Figure 4: The LXTBKZMCMG-010 UHF RAIN RFID tag is optimized for metal surfaces such as surgical instruments and industrial tools. (Image source: Murata)
Low profile RFID tags for asset tracking
Asset and inventory tracking applications can benefit from tags designed to survive high vibration and impacts and wide temperature variations found in industrial, agricultural, construction, and transportation systems. A low-profile footprint means less space, less damage, and lower costs. For example, the 0133580821 RFID tag from Molex is 1.8 mm thick, has an IP68 rating, can be used in wet environments, and operates from -50°C to +85°C (Figure 5). The 0133580821 has a 4.5-meter read range and is designed for use on a variety of materials, including metals and plastics.
Figure 5: This 1.8 mm thick RFID tag is optimized for asset and inventory tracking with a 4.5-meter read range and can be used on multiple surfaces, including plastics and metals. (Image source: Molex)
Plug and play RAIN RFID reader
The Elara RAIN RFID finished reader from ThingMagic has interface and operational features that minimize design efforts and speed RFID implementations in any application that requires read distances up to 2 meters (Figure 6). The Elara is offered in two models, the PLT-RFID-EL6-ULB-4-USB that operates in the 865 to 868 MegaHertz (MHz) band and the PLT-RFID-EL6-UHB-4-USB that operates in the 915 to 928 MHz band. Both readers come in enclosures made of healthcare qualified plastics.
Figure 6: The Elara RAIN RFID finished reader can minimize design efforts and speed RFID implementations in any application that requires read distances up to 2 meters. (Image source: ThingMagic)
Using Elara, designers can easily add RFID capabilities into applications that benefit from a plug-and-play desktop or fixed mount reader. Autonomous workflows are supported that enable rapid creation of solutions without RFID expertise on the part of the designer or the need for software development kits and integration tools. Examples of Elara applications include implementing UDI regulations in healthcare facilities, returns processing and tracking in warehouses and distribution centers, and commissioning RFID tags. Capabilities of Elara include:
- Simplified system integration and software-free operation using the pre-loaded autonomous workflows.
- Support for RAIN technology standards and RAIN communication interface.
- EPCglobal Gen 2v2 protocol support.
- Bulk reading of sets of items such as surgical instruments or a kit of components for an assembly line.
- Item counts and verification for returns processing or taking inventory.
- Commissioning RFID tags
- Updating tag data with usage and other information.
Industry 4.0 RFID reader and edge service device
For industry 4.0 applications that need multiple RFID readers and connection to the cloud through an edge server, designers can turn to the ALR-F800-X from Molex that includes a 4-port enterprise-class passive UHF RFID tag reader and an edge service controller (Figure 7). Using the ALR-F800-X enables RFID data to be processed at the source and evaluated in real-time. The ALR-F800 can be powered using either a dc power adapter or a Power-over-Ethernet (PoE) power source, simplifying deployment of large-scale Industry 4.0 RFID systems.
Figure 7: The ALR-F800-X includes a 4-port enterprise-class UHF passive RFID tag reader and an edge service controller to support Industry 4.0 applications. (Image source: Molex)
Dynamic self-adapting (DSA) technology in the ALR-F800 monitors the RF environment in real-time and controls several parameters, filters, and tuning metrics to optimize RFID tag reads. Memory can be added using micro-SD cards, and a USB port is available for adding Wi-Fi and cellular modem connections.
The built-in Emissary software enables support and configuration of additional readers and reads points without needing a dedicated edge server (Figure 8). Emissary software allows the development of complete workflows using pre-engineered activities (such as read tag, turn on light, send data, and so on) that simplify and speed the commissioning of new applications. Emissary includes:
- Structured and intuitive visualization of functions, devices, and read points.
- Use of common-sense naming conventions such as ‘wrap station’, ‘door #1’, and so on.
- Windows-based toolset for the creation of workflows.
- Set-up, control, and maintenance of all local readers connected to the device.
- Use of the correct Tag Data Standard for accurate interpretation of incoming data.
- Management of tag-read data reports and consolidation of reports from multiple readers for transfer to the cloud.
Passive RFID tags and readers can support various asset tracking activities in the IIoT, including manufacturing, logistics, data centers, health care, agricultural, construction, and transportation. When selecting and specifying RFID systems, designers need to be aware of a range of industry standards, including RAIN, EPC Gen 2v2, ISO/IEC 18000-63, and UDI regulations. Various types of tags are optimized for specific applications such as on-metal installations and low-profile designs for asset tracking applications. In addition to the tags, RFID readers are available, including desktop designs and enterprise-level readers/edge service controllers that can speed the deployment of Industry 4.0 RFID applications.
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