Editor's Choice


Tag-specific requirements in RFID systems for track and trace

September 2021 Editor's Choice Industrial Wireless

With particularly high frequencies, UHF RFID systems allow reading ranges of several metres. Tags, whose communication via the air interface is defined in accordance with ISO/IEC 18000-63 (EPC global Class 1 Gen 2), play a decisive role in this. If the chosen tags are, however, not suitable for the application, if they are not sufficiently durable to withstand the process or if they do not deliver the necessary performance (in terms of reading range), the reading rate of the RFID system will be too low or the entire system may fail. It is therefore necessary to understand the technical demands and physical conditions of the relevant process in as much detail as possible. These diverse conditions of different industries and applications generate a wide variety of tag-specific requirements, affecting aspects such as the design or the memory size. UHF RFID systems are being used for more applications all the time so the process of choosing the appropriate tag is becoming more and more complex.

1. Frequency ranges

In which region will the tag be used? There are basically three variants:

• ETSI (European Telecommunication Standard Institute): the tag is optimised for a frequency range of 865-868 MHz – this range is used in Europe, Russia and India, for example.

• FCC (Federal Communications Commission): the tag is optimised for a frequency range of 902-928 MHz – primarily used in America and Asia.

• Global: the tag functions over the wide frequency range of 860-960 MHz and can be used in all international regions.

When choosing a tag, it is essential to know where the tag will be used. Most South African industries fall under either the European or Global Regional Standard.


2. Material of the objects being identified

When choosing a tag, it is important to consider the surface on which the tag will be mounted. In certain circumstances, the read/write range can be greatly reduced by the electrical conductivity of the mounting surface. For example, the ends of the antenna will short-circuit if a conventional paper label is mounted on a metallic surface. As a result, the tag cannot be supplied with energy and is no longer readable. Other materials and substances that suppress the electric field include liquids, wood, textiles and plastics.

For some applications, special requirements are set out in the data sheet of the tag:

On-metal: these tags are suitable for mounting on metal. Insulating materials inside the tag prevent a short-circuit of the ends of the antenna. It is important to note that on-metal tags often function within a smaller frequency range. Different versions are therefore available for the ETSI and FCC frequency ranges.

High temperature: in certain processes, tags may be subjected to significant temperature fluctuations. Before choosing a tag, it is therefore important to know what operating and storage temperatures to expect and whether high temperatures occur occasionally or regularly. It should be tested how fast the tags heat up or cool down in the application. In this context, it is necessary to consider the expected number of cycles and thus the impact on the life expectancy of a tag.

How large the tag must be and where it can be mounted depends on the physical size of the object being tagged and the required reading range. In general, the size of the antenna structure on a tag has a significant impact on the reading range.

3. Tag design

Tags come in several body styles, based on application environments, ambient conditions and the ability to fulfil different requirements:

• Label: The antenna and chip are placed on a thin base layer and then covered with a thin film or printable paper. This type of tag is protected against mechanical stresses only to a very limited extent. If the tag is deformed because of impacts or bending, there is a risk that the connection between the antenna and the chip will break and the tag will no longer function.

• Hard tag: these comply with high protection classes up to IP69K and are made from materials that will not show cracks, breaks or other damage, even after a long service life.

• Sensor tag: combining sensors and RFID tags (labels and hard tags) is an interesting technical solution. In this case, familiar components of the tag, generally the antenna and IC, are enhanced by electronics for carrying out various measurements. Temperature and humidity measurements are often performed by sensor tags.

4. Memory buffer

What data and how much needs to be stored on the tag depends on:

• Scenario 1: the customer saves all process-relevant data on the tag. A high storage capacity is required. If the tag is lost or becomes faulty, all data will be lost.

• Scenario 2: the customer assigns only a unique ID and stores all process-relevant data in their own system. A low capacity is sufficient with 96 bits usually being enough.

Data can be stored in two memory buffers on the UHF tag:

1. EPC (electronic product code) memory: this memory buffer must be present in accordance with the EPC Global Class 1 Gen2 specification and is usually at least 12 bytes in size. It is suitable for assigning a unique ID and can be read in bulk. Multi-tag applications are possible.

2. User memory buffer: this is optional and can be up to several kilobytes in size, making it suitable for storing large amounts of data. However, since it cannot be read in bulk, multi-tag applications are not possible. It is possible to read the memory buffer of a specific tag within a group by specifying the EPC.

5. Optimum mounting method

There are several ways to mount a tag to an object, for instance, glue, screws, cable ties, potting, or welding. The optimum mounting method depends on the type of tag, the ambient conditions and the surface of the tag.

6. RFID systems from a single source

The BL ident complete RFID system from Turck Banner offers solutions in the HF or UHF range with interfaces for use in a plant or switch cabinet. Since 2006, this RFID system has been used successfully in industrial environments and is being developed continuously. Over the years, Turck Banner specialists have acquired in-depth practical expertise that users can benefit from in their own RFID projects. For highly-complicated applications, integration partner, Turck Vilant Systems, operates a proven middleware system to help smooth integration of UHF systems into specific processes. The company has demonstrated its expertise in integrating solutions in MES and ERP systems through several complex projects. Full transparency along entire supply chains can be achieved through reliable detection of goods at RFID checkpoints using simple, cost-effective labels https://tinyurl.com/7dmr2326.

Advantages

More efficient processes in production and logistics:

• Avoid time-consuming manual work steps and simplify inventory management.

• End-to-end identification and tracking of goods flow.

• Bulk reading – detect several tags at the same time.

Improved quality control

• Eliminate errors, for example, during tool change or material feed.

• Full transparency along the supply chain thanks to the clear allocation of goods.

• Tamper protection via individual coding.

Future-proof investment with high flexibility

• Expandable RFID system consisting of tags, read/write heads, interfaces, connectivity and fieldbus technology.

• Rewritable tags for sustainable use.

• Combination of HF and UHF detection for complex or new requirements.


Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Wide-beam radar sensor
October 2021, Turck Banner , Sensors & Transducers
Turck Banner’s T30R series has been expanded with a wider-angle (45°×45°) beam pattern sensor to better detect curved or reflective surfaces and larger targets.

Read more...
Loop Signatures 9: Digital controllers – Part 1: Introduction to the simple PID controller
October 2021, Michael Brown Control Engineering , Editor's Choice
There is a commonly held belief in control circles that all PID controllers are similar and relatively simple. This is a dangerous fallacy.

Read more...
DEK wireless kit
October 2021, Turck Banner , Industrial Wireless
The standalone DEK wireless kit from Turck Banner includes everything needed for a remote preventive maintenance monitoring solution.

Read more...
Turck Banner’s Profinet integration with S2 redundancy
October 2021, Turck Banner , Fieldbus & Industrial Networking
The TBEN-L5-8IOL is an IO-Link master module in IP67 that supports S2 system redundancy. The master establishes a logical communication relation to more than one controller and combines high availability with a wide range of potential uses through IO-Link in the field.

Read more...
Totally Integrated Automation – added value in three dimensions
October 2021, Siemens Digital Industries , Editor's Choice, System Integration & Control Systems Design
Discover everything that’s in TIA, the leading automation concept from Siemens, and how it all works together to create a unique product for machine builders and industrial enterprises.

Read more...
Cybersecurity for operational technology: Part 3: Third-party supplier risks to OT Systems
October 2021, Wolfpack Information Risk , Editor's Choice
As supply chains have become integrated, interconnected and increasingly complex, supply chain cyber-attacks are on the increase as they are very effective.

Read more...
Case History 179: Some unusual measurement and control problems
September 2021, Michael Brown Control Engineering , Editor's Choice
The example given in this article illustrates some mistakes made by the system integrators and control engineers at a metals extraction plant that used a well-known make of PLC and scada for its controls.

Read more...
Security for operational technology: Part 2: How much of a cyber threat are people to OT systems and what can be done?
September 2021, Wolfpack Information Risk , Editor's Choice
The recent cyber-attack on Transnet is a wake-up call that South African companies are not immune from cyber threats.

Read more...
All-in-one sensor allows quick deployment
September 2021, Turck Banner , Sensors & Transducers
Turck Banner’s photoelectric Q45 family combines sensor, wireless node and battery in a single, compact unit.

Read more...
E-stops with protective shrouds
September 2021, Turck Banner , Operator Interfaces, Switches & Relays
Turck Banner now offers variations of its popular emergency stop controls with a durable protective shroud. The shroud has a sturdy one-piece design that ensures safe and consistent operation for the ...

Read more...