Know Your RFID Frequency Basics

In 2008 I purchased my first toll road RFID transponder, letting me drive through and pay my toll without stopping at a booth. This was my first real-life exposure to RFID, and it was magical. Back then, all I knew was that RFID stood for “radio frequency identification” and that it exchanged data between a transmitter and receiver using radio waves. That’s enough for a highway driver, but you’ll need more information to use RFID in an industrial automation setting. So here are some basics on what makes up an RFID system and the uses of different radio frequencies.

At a minimum, an RFID system comprises a tag, an antenna, and a processor. Tags, also known as data carriers, can be active or passive. Active tags have a built-in power source, and passive tags are powered by the electromagnetic field emitted by the antenna and are dormant otherwise. Active tags have a much longer range than passive tags. But passive tags are most commonly used in industrial RFID applications due to lower component costs and no maintenance requirements.

Low frequency (LF), high frequency (HF), ultra-high frequency (UHF)

The next big topic is the different frequency ranges used by RFID: low frequency (LF), high frequency (HF), and ultra-high frequency (UHF). What do they mean? LF systems operate at a frequency range of 125…135 kHz, HF systems operate at 13.56 MHz, and UHF systems operate at a frequency range of 840…960 MHz. This tells you that the systems are not compatible with each other and that you must choose the tag, antenna, and processor unit from a single system for it to work properly. This also means that the LF, HF, and UHF systems will not interfere with each other, so you can install different types of RFID systems in a plant without running a risk of interference or crosstalk issues between them or any other radio communications technology.

 

Choosing the correct system frequency?

How do you choose the correct system frequency? The main difference between LF/HF systems and UHF systems is the coupling between the tags and the antenna/processor. LF and HF RFID systems use inductive coupling, where an inductive coil on the antenna head is energized to generate an inductive field. When a tag is present in that inductive field, it will be energized and begin communications back and forth. Using the specifications of the tag and the antenna/processor, it is easy to determine the read/write range or the air gap between the tag and the antenna head.

The downside of using LF/HF RFID technology based on inductive coupling is that the read/write range is relatively short, and it’s dependent on the physical size of the coils in the antenna head and the tag. The bigger the antenna and tag combination, the greater the read/write distance or the air gap between the antenna and the tag. The best LF and HF RFID uses are in close-range part tracking and production control where you need to read/write data to a single tag at a time.

UHF RFID systems use electromagnetic wave coupling to transmit power and data over radio waves between the antenna and the tag. The Federal Communications Commission strictly regulates the power level and frequency range of the radio waves, and there are different frequency range specifications depending on the country or region where the UHF RFID system is being used. In the United States, the frequency is limited to a range between 902 and 928MHz. Europe, China, and Japan have different operating range specifications based on their regulations, so you must select the correct frequency range based on the system’s location.

Using radio waves enables UHF RFID systems to achieve a much greater read/write range than inductive coupling-based RFID systems. UHF RFID read/write distance range varies based on transmission power, environmental interference, and the size of the UHF RFID tag, but can be as large as 6 meters or 20 feet. Environmental interferences such as metal structures or liquids, including human bodies, can deflect or absorb radio waves and significantly impact the performance and reliability of a UHF RFID system. UHF RFID systems are great at detecting multiple tags at greater distances, making them well suited for traceability and intralogistics applications. They are not well suited for single tag detection applications, especially if surrounded by metal structures.

Because of the impact an environment has on UHF signals, it is advisable to conduct a full feasibility study by the vendor of the UHF RFID system before the system solution is purchased to ensure that the system will meet the application requirements. This includes bringing in the equipment needed, such as tags, antennas, processors, and mounting brackets to the point of use to ensure reliable transmission of data between the tag and the antenna and testing the system performance in normal working conditions. Performing a feasibility study reduces the risk of the system not meeting the customer’s expectations or application requirements.

Selecting an industrial RFID system

There are other factors to consider when selecting an industrial RFID system, but this summary is a good place to start:

    • Most industrial RFID applications use passive RFID tags due to their lower component costs and no battery replacement needs.
    • For applications requiring short distance and single tag detection, LF or HF RFID systems are recommended.
    • For applications where long-distance and multi-tag detection is needed, UHF RFID systems are recommended.
    • If you are considering UHF, a feasibility study is highly recommended to ensure that the UHF RFID system will perform as intended and meet your requirements.

Click here to browse our library of Automation Insights blogs related to RFID.

UHF RFID Versus UHF RTLS

Many companies new to UHF (Ultra High Frequency) RFID (Radio Frequency Identification) confuse it with UHF RTLS (Real Time Location Systems). While both indeed do use UHF RFID, they differ substantially in what they can actually do for you in your business.

Many companies new to UHF (Ultra High Frequency) RFID (Radio Frequency Identification) confuse it with UHF RTLS (Real Time Location Systems). While both indeed do use UHF RFID, they differ substantially in what they can actually do for you in your business.
UHF RFID

Standard UHF RFID systems can see multiple tags on equipment and products up to several meters away, if set up properly. With emphasis on “set up properly.” While UHF RFID works quite well, its unique characteristics require testing in the environment where it will be used to ensure success.

UHF RFID has several purposes:

    • To see if an item has passed a certain point, commonly known as a choke point. Examples of this are items being loaded on or off a trailer at a shipping door or items passing from one area to another in a plant.
    • To verify if something is within a certain area when using a scanning device, such as a handheld reader. If one is scanning shelves of parts or equipment, it will help locate those items.
    • To track usage of equipment in MIS systems.
    • The tags can also have data written to them if needed.

The big thing that UHF RFID cannot do is effectively track the exact location of something at any given time in a cost-effective manner. Generally, UHF RFID uses what are called passive tags for the antennas to read. These tags have no battery and get energized from the antenna signal. If you placed enough antennas all over a facility and enough of these tags, then you could possibly locate something within a certain proximity, but not exactly, and this is hardly cost effective.

UHF Real Time Location Systems (RTLSs)

RTLS, on the other hand, are specifically designed to pinpoint the location of anything with a tag or transponder on it. In fact, RTLS refers to any system that can accurately determine an item or person’s location. An important aspect of RTLS is how frequently assets must be tracked. This data can be used in different ways depending on the application. For example, some RTLS applications only need timestamps when an asset passes through an area, while others require much higher visibility, requiring constant updating of time data.

An ideal RTLS can accurately locate, track, and manage assets, inventory, or people, and help companies make knowledgeable decisions based on collected location data.

Like regular UHF RFID, RTLS can use passive or active tags (tags with batteries), but they use triangulation of multiple antennas to determine the location of an object or person. The strength of the signal at each antenna, combined with the software attached to the antennas, allows the identification of the location of an object or person within less than 1 meter.

The system you choose depends on the needs at your location. They both work quite well when implemented properly by trained professionals.

Also, due to the inherent properties of ultra-high frequencies used in UHF RFID technology and RTLS, you should perform a feasibility study that actually tests the system in the real world environment of the plant prior to implementing these systems in any application.

Increase Competitiveness with RFID in the Intralogistics Industry

In times of globalization and high labor costs it is a challenge to increase competitiveness in the fashion industry. Within a warehouse, an RFID system supports a high degree of automation as well as short transport distances. To supply dealers and to keep their facility profitable, one of the most successful fashion companies in the world has built a highly modern hanging garment distribution center. Let’s take a look at how they successfully implemented RFID technology to improve their processes.

Separate and sort clothes with just one hybrid module (2D code + RFID)

Within this distribution center 45,000 of these innovative clothes hanger adapters (L-VIS) are used. They replace the previous trolley-based logistics approach by allowing the transportation of a number of different garments that have the same destination.

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L-VIS, clothes hanging adapter made by P.E.P. Fördertechnik

With the investment in some additional space in the so-called buffer or storage zone, and by providing empty trolleys at various locations to keep the product flow moving, this project is successfully accomplished. A major advantage of this system, is the usability over the entire intralogistics chain. From receiving, to the hanging storage, to the sorter for single item identification, and from there as a transport unit to shipping.

The clothes hanger contains an RFID chip, that is automatically read by the conveying technology, and the 2D-code. This code is read manually by employees with a portable acquisition unit. The code can be DMC (Data Matrix Code), QR-Code, or any other optical code standard.

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HUGO BOSS garment distribution center (Metzingen, Germany)

Information exchange without visual contact

A high frequency RFID chip is installed. With this identification system, neither direct alignment nor contact is needed to enable data exchange via nearfield communication. Non-contact identification is extremely reliable and wear-free. The identification system consists of a rugged data carrier, a read/write head and an RFID processor unit. The processor unit communicates to the control system via Profibus, but could be accomplished with ProfiNet or EtherNet/IP as well.

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BIS-M RFID processor unit

The following table gives you an overview of types of Radio Frequency Identification solutions that are available on the market:

Common Types Low Frequency Low Frequency High Frequency Ultra High Frequency
Frequency 70/455 kHz 125 kHz 13.56 MHz 860 … 960 MHz
Short description Dedicated solution to tool identification in Metal-Working industry. Standard solutions for simple Track & Trace applications. Fast & reliable – even with high volumes of data in medium distances in assembly, production and intralogistics. Identification at large distances and bunching capability for current material flow concept.

For the customer, the decision to choose this particular system among others was the separation between the processor and read/write head. In a widespread facility it would not make sense to have a decoder with 30 read/write heads attached. By interfacing two read/write heads per processor, it is possible to track the travel of a transport unit over the entire conveyor line as well as track within the aisles between the individual shelves.

An additional advantage of the system implemented is the housing options. The L-VIS carrier and the 30 mm read/write head are an ideal match. The simple mounting of the processors and ready-to-use connection were of high value to the system integrators. In the sorting area, a 2D code was supplemented by the RFID tags to reach speeds of up to 0.6 and 0.7 m/s. This would probably not have been possible with the installation of a corresponding camera technology.

Experiences have shown, that RFID projects need a lot of support. Consultation and assistance from true experts can be provided by our team. Learn more about RFID technology here.

Passive RFID Still the Way To Go For Work In Process (WIP)

With the rapid evolution of manufacturing technology it’s pretty tough to keep up with the latest and greatest products designed to help automate the manufacturing process. The big “buzz” surrounding RFID about a decade or so ago was Wal-Mart declaring that their top one hundred vendors would be required to tag every single item with an RFID tag. Well, that never came to fruition. Around the same time there was a lot of talk about active RFID systems as a new technology for work in process. Well, that didn’t ever quite materialize either.

While the active systems certainly have made an impact on yard and container management applications, passive RFID still rules the roost in WIP. In essence, the main difference between passive and active RFID is active tags require a battery which helps tagsto yield a much larger read range. One can imagine the benefits of an extremely long read range in a shipping yard, but on a production line the engineers are just fine with mounting the read head within a few inches of the work pieces. Eighty to ninety percent of the new WIP applications that we deal with still require High Frequency (HF) technology.   The other ten to twenty percent are using Ultra-High Frequency (UHF) which is still passive technology, just a longer read range. This is usually the case where the actual item being built is very large and it is very difficult to place a HF reader within inches of the work piece.

Ultimately, using active RFID for work in process is similar to using a sledge hammer to put a nail in a wall. It is simply overkill. So, while automation technology is on a course of change, it is clear that some of the “old faithful” equipment is still adequately addressing the needs on the production line.

To learn more about active vs. passive RFID tags, click here.

Die Identification – A Critical Part of the Stamping Operation

DieCrashIt’s one thing to stamp out a bunch of bad parts because the die hasn’t been properly maintained, but it is another to suffer through a crash because the wrong shut height was set. Failure means hours or even days of downtime and hundreds of thousands of dollars in repair expenses. The fact is, both are preventable with a very simple RFID solution.

Let’s face it, stamping presses aren’t the most technologically advanced machines in our industry. With all the multi-axis, CNC driven machines out there nowadays a press can look somewhat archaic. However, they are one of the most widely utilized machines across the globe today and have been for many years. I can’t say how many times I have walked into a press shop and witnessed 30 year old presses in full operation. So while they may be the dinosaurs in the world of machines, their flawless operation is critical.

One sure way to protect this critical process is to incorporate RFID. Simply affixing an RFID tag to the die can inform the operator of the following:

  • Die location
  • Use Data
  • Repair Data
  • Setup Data
  • Shut Height
  • Feed Material
  • Correct Transfers
  • Number of Hits

All this information is recorded to the tag’s memory and can be read with either a handheld or fixed reader. Since the tag can be read and written to, the information on the tag can be updated after every job or periodic maintenance.

Everyone knows that properly maintained tools extend the life of equipment and help ensure quality products are being produced, but recording this data is another story. The safest and most secure method of recording data about a die is RFID. There are no documents to lose, or illegible handwriting to decipher because the RFID tag is secured directly to the die. Incorporating a die protection program is certainly not a major undertaking. On the contrary, recovering from a crash can cause a major strain on time and resources.

Learn more about solutions for the Metal Stamping industry by visiting Balluff’s website.

Back to Basics: The Fundamentals of a Passive RFID System

There has been a lot of talk in the industrial automation about RFID. In past blog posts we’ve discussed topics like RFID ROI and when to use IO-Link RFID. We could talk about things to consider when implementing RFID into your plant or different applications for days. In this entry, though, I’d like to get back to the basics a little bit.

Area of Application for a Passive RFID System:

RFID is used to accurately identify an object on which the tag is placed. In addition to identification, bject-specific information, like maintenance data is contained on the tag.

Typical RFID System
Typical RFID System

How It Works:

Since passive RFID tags contain no battery, the tag is powered up or “woke up” by the RF waves emitted from antenna of the same frequency. Once a tag is located in range it is powered up by the antenna and its memory can be read and transmitted to the processor. The time it takes the reader to extract information from the tag is usually measured in milliseconds.

Three Main Components of a Passive RFID System:


RFID-TagTag
– A combination of a chip and internal coil. The chip is where the data is held in the memory and can contain a few bytes of data or thousands of bytes of data depending on the capacity of the chip.

RFID-AntennaAntenna – Connected to the processor by an external cable or sometimes contained inside the same housing, the antenna transmits the data to and from the tag back through the processor

RFID-Processor Processor – The role of the processor is to organize the data as it is being read or written. The processor is usually connected to a controller, like a PC or PLC, and performs the task issued by the controller.

To learn more about industrial RFID applications and components visit www.balluff.us/rifd.

Customization of RFID tag holders and mounting accessories

Does your RFID application require a customized tag holder? What about special brackets for read/write heads and processors? Don’t have the bandwidth to design the mounting hardware required for your unique application? The Balluff Customizing Group can help! If you are implementing the BIS C, BIS L, BIS M or BIS U RFID systems we will make sure you get the performance your application demands.

For several years the Balluff Customizing Group has been working directly with engineers and maintenance personal to provide design and development services for RFID mechanical accessories. The process is streamlined and very straight forward. Please contact Balluff’s Technical Support Professionals to discuss your RFID application.

Here are a few recent examples of RFID projects in the Customizing Group:

1) RFID Pistol Grip Read/Write Head for BIS M data carriers. The modular design can be used with M12, M18 and M30 tubular read/write heads for logistics tracking of incoming and outgoing shipments.

PistolGrip

2) Keyfob with embedded BIS C data carrier. Individual access codes are programmed to the tags allowing only authorized personnel to enter restricted areas.

Keyfob Keyfob2

3) BIS M read/write data carriers embedded in stainless steel NPT plug for Production Tracking.

DataCarrier

RFID – It’s Not a Matter of Privacy

With the recent boom in RFID implementations by organizations all over the globe, there is a buzz in the on-line communities and social networking sites about how the technology is an attempt to invade the privacy of every “Jane and Joe” on the planet. I have to admit when I first started to come across these public concerns I just assumed this was the vocal minority being overly paranoid. However, as the technology has progressed into many different areas of our life it has become pretty clear that little has been done to address the concerns of the public. So, I am going to address a few of those concerns here.

Recently, the GM plant in Tonawanda, NY incorporated RFID into their engine production process. They simply attach a Balluff Databolt (a specialized bolt with an RFID tag embedded in it) to every engine before it goes onto the assembly line. As with many manufacturing processes the engine will go to many different stations to be assembled and tested. At each of these stations data from the previous station is read and new data is written to the tag to ensure everything in the process went as planned. When the engine is completed the information written on the tag is uploaded to GM’s database and stored. In addition, the tag is removed, its memory erased and placed on another engine that goes through the same process. The tag DOES NOT stay with the engine. And, even if it did there would be no way to secretly track your vehicle by “pinging” this tag.

The GM example is just one of tens of thousands of applications where RFID is used to ensure quality, manage the production process, and manage product recalls in the manufacturing world. So, what about other applications like in retail where clothing is tracked via RFID or the livestock or pet industry where a small RFID tag is implanted in the animal?

Continue reading “RFID – It’s Not a Matter of Privacy”

WOW! It’s a bolt!?

Our Databolt never fails to grab the attention of everyone who has ever ventured to take a look in my sample case. In a kit of a hundred plus RFID tags which vary in frequency and form factor, it’s the one that draws the most questions, by far. Without a doubt, it is unique, it is rugged, and it is a pretty ingenious method of attaching an RFID tag to an item that needs to be identified and tracked through a process.  However, I couldn’t help but think…it’s just a bolt.

If you have ever been to a manufacturing trade show then you know that the “wow factor” is pretty common in this industry. From Blackjack dealing robots to machines the size of a typical suburban home, you must admit there is some impressive stuff out there.

Never did I consider the Databolt a “wow” product until a recent issue of Popular Mechanics featured the Balluff Databolt in an article regarding RFID traceability at GM’s engine plant in Tonawanda, NY. After reading the article I realized that wow can mean different things. So when I see a friend I haven’t seen for fifteen years and the first thing they say is wow. Is it wow, I haven’t seen you for a long time? Or wow, you’ve gained sixty pounds and are losing your hair? I guess it is to be left open for interpretation.

My vanity aside, it is now pretty clear that when the Databolt produces a wow, it is not necessarily a wow, this is the coolest piece of technology I have ever seen. More accurately, it is most likely wow, this simple little bolt can save my company millions by:

  • Creating visibility into the production process
  • Helping to comply with regulatory and quality standards
  • Proactively managing product recalls with near-real-time corrective action
  • Improving customer safety and satisfaction
  • Reducing the cost of nonconformance

So, that is my take on what people really mean when they say “wow” in regards to the Databolt. Check out the article and determine for yourself how wow should be interpreted.

http://www.popularmechanics.com/cars/news/industry/this-bolt-is-the-key-to-gms-high-tech-assembly-line-16324897

Flexibility: A Key to success in manufacturing

My ol’ ball coaches used to say: “be ready for anything”, “we have to make changes on the fly”, “we can’t be one dimensional”.  They all could have summed it by saying: “you gotta be flexible”. They all had it exactly right and that has proved to be true in all arenas of competition. In sports or manufacturing, the team that is capable of being flexible is the team that gets the win in the long haul.

The cost to get an idea to market is a key factor in determining whether or not an organization can make its foray into the future.  In the manufacturing world the product isn’t the idea, but a tangible good. The cost tied to a product begins to accumulate in the idea stage and continues all the way through to building the product and transporting it to market.  Even after the product has reached the market there are costs associated with sales, support, etc.  All too often manufacturers are handcuffed to running one product per line…Or should I say, doing that efficiently?  RFID has enabled manufacturers and specifically process engineers to perform changes and make alterations in midstream while saving on cost and improving quality. At the same time, the technology creates open lines of communication between operators and personnel on multiple shifts.

Continue reading “Flexibility: A Key to success in manufacturing”