RFID UNCOVERED

Radio frequency identification (RFID) is changing the way companies do business. Cutting through all the hype, the basic business benefit of RFID technology is improved asset visibility. There is no company in the world that cannot profit from having a more accurate picture of what it has and where it’s located.

New and exciting applications for RFID technology are being realized every day. This article is meant to provide only a glimpse into how companies are currently applying the technology. Every company has its unique processes and systems. It is important to be creative when designing an RFID system. If you do, the potential can be great

BACK TO BASICS

To get started, everyone should have a basic understanding of RFID. There are four basic components to every RFID system:

1. RFID Tags

RFID tags are affixed to assets. Each has a unique numerical identifier so differentiation is possible. For supply chain operations, it is common for the tag identifier to contain the serialized global trading identification number (SGTIN) of the item to which it is affixed. This allows diff erentiation of identical items.

2. Interrogators (or readers)

An interrogator, or more often called a reader, is a radio frequency transmitting and receiving device used to communicate with an RFID tag. The device was named an interrogator because it actually interrogates the tags. The term “reader” is more colloquial, but is sometimes misleading in that many of these devices also have the ability to encode, or write information to an RFID tag. A reader basically acts as a sensor because it senses what tags are within its range.

3. Antennas

One or more antennas are connected to the reader and are required for the radio frequency communications between the tag and the reader. Antennas come in a variety of size and shapes and have a significant impact on read range and performance.

4. Information Processing

In order to obtain any tangible benefit from RFID technology, readers must be connected to an information processing system, which provides instructions to the readers, coordinates their operation, collects output data, and most importantly, makes decisions based on business rules about the data it receives. These software programs are sometimes called “middleware” or “edgeware” but we prefer to call them Intelligent Sensor Network Platforms because RFID readers typically need to be coordinated with other industrial sensing and automation devices.

THE RFID SYSTEM

An RFID read point refers to a specific antenna connected to a reader. A read zone is a logical grouping of one or more read points. It is important to point out that the read points comprising a read zone are not necessarily connected to the same reader. For example: Read Zone Alpha may be made up of Antenna 1 and 2 from Reader 5, and Antenna 3 and 4 from Reader 6.

The primary function of an RFID reader is to report state changes to its environment. A change in state is called an event. There are three types of RFIDrelated events:

1. A New Tag event occurs when a tag appears to a reader for the fi rst time.

2. A Visibility Changed event occurs when the visibility of a tag changes for a read point.

3. A Tag Not Visible event occurs when a tag is no longer visible to any read point.

A reader captures events along with the date, time, and data from the RFID tag(s) that caused the event to occur. The real benefit is realized from the ability to make decisions based on the events reported from multiple readers. That’s where the information processing systems come in.

Edgeware or middleware aggregates and filters the event data coming from the readers and may even make decisions based on a defined set of rules. The software may be operating on a standalone computer, or an industrial appliance designed specifically for this purpose.

In addition to the four basic components – reader, tags, antennas, middleware – more sophisticated RFID systems incorporate monitoring and sensing devices such as electronic switches, photo-eyes, and motion sensors. The events from these devices are combined with the RFID related events for improved decision processing. For example, when the dock door switch is on (door is open), power on the RFID reader, and store all RFID events into the database.

RFID systems are often connected to warehouse automation systems that are made up of devices such as programmable logic controllers (PLCs). The events generated by the RFID system triggers these devices to perform various operations. For example: When the RFID reader reports tag “12345”, illuminate a stack light

When determining where RFID technology should be applied within a supply chain, ask, “Where can we benefit from asset visibility?” Typically, asset visibility is desired when movement occurs, e.g. when the product comes in the dock door, when the product is shelved in the distribution center.

Chances are someone in your organization asked where visibility would be useful when designing the manufacturing plants, distribution centers, and other locations across your supply chain. Most likely, these locations have some type of automatic identification (auto-ID) technology already in place, such as a bar code scanner.

Manual methods of identification are also very common. Indeed, the standard to which all other identification methods are measured is still a person with paper and clipboard counting what he sees.

CLEAR ADVANTAGES

Contrary to what you may have read, RFID will not completely replace bar codes. Just as human readable information is still used in conjunction with bar codes, RFID technology will compliment barcode technology. RFID only makes sense where it provides advantages over bar codes.

The more advantages that can be applied, the greater the value of using RFID over an alternative method of identifi cation. There are five clear benefits:

Speed

An RFID reader can read tags faster than a bar code scanner can scan barcodes. RFID readers designed for supply chain operations can perform between up to 1,500 read operations per second.

Read Distance

Depending on the equipment configuration, it is not uncommon to read RFID tags at distances of three meters between the tag and the antenna. This area is commonly referred to as the “read field”. The size and shape of the read field may be controlled by adjusting reader power settings, antenna selection, antenna placement, and other techniques. A read field is three dimensional in that its size may be measured using X, Y, and Z dimensions.

Simultaneous v sequential scanning

RFID readers can identify multiple tags within the read field. The most common application of this capability is for the reader to report all tags within its read field.

Non-line of sight

Depending on the frequency being used, radio waves can penetrate most materials. When using the standards being adopted for RFID in supply chain operations there are challenges when working with materials that contain liquid or metal. However, there are proven methods for working around these challenges.

Durability

RFID tags can still operate even if they get dirty. RFID tags can be hardened by encasing them in plastic. Some companies have even embedded RFID tags directly into the products they manufacture.

There are numerous locations within a facility to apply RFID technology. We’ll focus on some of the more common industrial and retail locations and the benefits companies are realizing from improved asset visibility using RFID technology.

INDUSTRIAL LOCATIONS

For the purposes of this article, the industrial locations described below are assumed to be in such places as a warehouse, a distribution center (DC), or a manufacturing plant. These facilities are common in most supply chain operations.

Through the doors

An RFID-enabled portal is a doorway through which goods travel. There are several configurations of portals, but the most common is the dock door. RFID technology is used at portal locations because all of the benefits described above may be realized.

As pallets and cases of RFID tagged items move through the portal, they may be rapidly identified even when traveling via materials handling equipment, such as a forklift. Often, it is important to know the direction in which the product is traveling. Directionality can be determined by using one of two methods: calculated or assumed.

Calculating directionality is the most accurate method to determine the path of an item. This works by comparing the outputs of two or more read points. When a tag is seen in read zone A, and then in read zone B, it can be determined that the tag is moving in the direction from A to B. This is an extremely simplistic description of a much more complicated algorithm.

Assuming directionality is the simpler of the two methods, but not always possible or accurate. For example, if a dock door is dedicated for only outbound shipping functions, then it can be assumed that when a tag is seen there, it is traveling out through the door. The problem with this assumption is that goods are often loaded, unloaded, and reloaded again. Assuming directionality does not take this process into account.

The toughest challenge to RFID-enabled portals is in environments that have multiple adjacent portals. Overlapping read fields can result in multiple readers reporting the same RFID tag is present. It is important to determine what read zone the tag is closest to before load verification can be performed or an inventory update made.

There are several methods that help with overlapping read fields. Linking the RFID reader power-on/power-off to the door being opened and closed is the simplest and easiest method. If the portal door is closed, product is not going to be traveling through it.

Alternatively, carefully configure the read field. There are methods to control the size and shape of the read field so that adjacent fields do not overlap. Unfortunately, no matter how well defined the read field, RF reflections will occur and cannot be completely eliminated. However, edgeware or middleware that provides filtering capability can be used to make an intelligent assumption as to the closest read point to a tag.

The most common portal applications are described below:

• Inbound Receiving Doors

RFID-enabled receiving doors can provide automatic inventory updates for received goods. Retailers are using RFID for verification that the products actually received match the contents of the advanced shipping notice (ASN). By combining RFID with display terminals, operations personnel can be instructed what to do with the product just received (e.g. “place this case in the special orders pile”).

• Outbound Shipping Doors

The benefit to RFID-enabled outbound shipping doors is predominately in verifi cation. Not only can RFID ensure that the goods being loaded onto the right truck, it can also verify that products are loaded in the proper sequence. This is especially important with full pallets on trailers with multiple destinations. It prevents one company from having to move another company’s product to access their own pallets.

• Inter-facility Doors

Multiple facilities may be built next to each other. For example, a manufacturing plant may be located adjacent to a distribution center. Finished goods may be moved from one facility to the other. An RFID portal installed in the routes that connect these facilities can automate the transfer process.

• Hybrid Doors

In smaller facilities, it is not uncommon to use dock doors for both inbound and outbound operations. For these portals, the directionality must be calculated. The addition of a manual switch can allow an operator to specify what task the door is currently serving: shipping or receiving.

• Storage

This is where a trailer is used as an actual storage location. This is not very common and typically only found in facilities that are near capacity or have shipments that are seasonal. Directionality is important in that it is important to know if the products have been put in or taken out.

ON THE SHELF

Just as an item or product is tracked on its journey into the warehouse, it is equally important to know where it resides in the facility for easy retrieval and verification. Although still too expensive for most companies to implement throughout the warehouse, some companies are RFID-enabling storage locations.

By using a shelf antenna for small goods or location antennas behind larger items, inventory can be automatically updated as products are picked or put-away. Not only does this create a much more real-time inventory, but it also frees operators from performing bar code scanning or manually writing product relocation tickets, which have to be keyed in later.

Operators can be given instant feedback when putting goods in the wrong location, or as some advanced business models have demonstrated, products can be placed in any open location because the RFID technology instantly captures where the product is put away.

Therefore, it doesn’t matter what location it’s in because you can always find it.

Mobile reads

Working with an RFID-enabled hand-held unit is not like working with a hand-held barcode scanner. An RFID hand-held unit will scan multiple RFID tags in its read field, i.e. simultaneous scanning as opposed to sequential scanning.

Hand-held RFID readers are being used in a way that barcode scanners cannot: product location. When the reader is placed in a “search” mode, an audible tone is heard as the hand-held gets closer to the tag being located.

The closer the operator holds the handheld scanner to the tag, the more rapidly it beeps. Because many of these units perform both bar code and RFID scanning functions, companies are opting to replace older units with newer, multifunction models.

Instead of using shelf or location antennas, RFID readers can also be mounted on to materials handling equipment such as forklifts or clamptrucks. By combining RFID with positional tracking of the equipment, real- time visibility of moving goods can be seen. Companies know what the forklift is carrying and where it is driving.

The primary goal is not only more realtime inventory control, but also reduction of unnecessary work. System verification can ensure that anytime an operator touches a product, they’re touching the correct product, for the correct reason, at the correct time, and performing the correct action with it.

Conveyance systems

One of the advantages of RFID technology over bar codes is that it does not require a line of sight to scan. If an item is traveling on a conveyor but is not oriented properly, it will still read if the read zone is designed well. In some situations, RFID performs so much more rapidly than barcodes the speed of the conveyor may be increased for faster throughput. RFID equipment is often combined with conveyor diverters to control product flow to the correct destination.

If the tag is already applied to an item traveling on a conveyor, an interrogator can encode the tag. This technique is used for some work-in-progress management applications. The serial number of the item is encoded on the tag at the first stage. As the tagged product goes through the assembly process, its location can be automatically determined. Depending on the RFID technology in use, products on a conveyor may have to come to a complete stop to allow time for the tag to be encoded. Palletizer/Stretch Wrap Machine An ideal location for asset visibility is where pallet loads are built. What better time to automatically verify the contents of the pallet? If there is a case that should not be included, or a product is missing, a visual or audible confirmation can be given to operations personnel that a problem exists and needs to be corrected.

It’s also a great time to capture metrics, for example, how long did it take between the tag application and the pallet being completed? It’s also a good time because the pallet is often bound for the next step in the process: staging or outbound shipping.

Staging/Holding area

Staging or holding areas are important locations for asset visibility. Knowing that a product was just received but not yet put away can save warehouse personnel valuable time. Creating RFID enabled read locations such as inbound and outbound staging, as well as qualityhold and repair locations greatly reduce times searching for ‘missing’ products.

RETAIL LOCATIONS (STORES)

The primary objective of RFID-enabled read points in a retail location is to determine in which area of the building was the product last visible. Retail locations achieve the greatest benefi t from using RFID tags at the item level.

Item-level tagging is already occurring for products where the item is treated as a case. For example, electronics items such as large televisions or DVD players are tagged at the item level. Some pharmaceutical products are also being tagged at the item or pack level, e.g. a bottle of vitamins, a box of cold pills.

Sales Floor

RFID locations and applications out on the sales floor:

• Shelf units and displays

RFID-enabled shelves and display units currently carry a high price tag but they provide retailers and consumers with abilities that never existed before. The primary benefit to retailers is inventory control and automatic alerts. Alerts automatically notify store personnel when an item is placed in the wrong location so that it may be put back where it belongs. This results in faster replenishment of goods and fewer out-of-stocks.

Clothing and apparel companies especially benefit from RFID because it is very labor intensive to ensure all of the available sizes, colors, or other variations are on the sales floor. Even though the display may be filled with products, an alert is generated when a particular size is out of stock. Consumers benefit because their favorite product or their specific size is on the shelf.

For date-sensitive inventory (DSI), an automatic notification can be generated when goods expire. Store personnel can proactively restock with fresh product. This ensures consumers will not purchase expired goods.

Yet another benefit is security. For items that are frequently stolen, special displays can be made. One manufacturer built a display unit that includes a digital camera. If more than three items were removed in under one second, then the camera took a picture of the customer and notifi ed security. The retailer can then ensure that the items are processed by the point-ofsale.

• Hot spots

Taking the RFID-enabled shelf and display to the next level, retailers are developing specifi c locations or “hot spots” where consumers can bring RFID tagged products and obtain information about the product.

When an RFID tag is read, a monitor next to the hotspot displays information about the product the customer has in hand. The customer can check stock levels, go to the product website, find accessories, special order a diff erent color, or any other action the retailer chooses.

One such hotspot is called a “magic mirror”. An RFID reader and a monitor are placed behind a mirror and are automatically activated when an RFID tag comes into the read field. To the customer, a virtual attendant behind the mirror appears to be speaking about the product

• Dressing Room

A magic mirror is very useful in a dressing room. If combined with a touch screen, a customer can automatically request that a live attendant bring a different size of the item being tried. This is a real convenience for the consumer and retailers benefit from the added security of knowing exactly what items are in the dressing rooms. Automatic alerts can be generated to restock items that a customer leaves in the dressing room.

• Point-of-Sale (POS)

Anyone that has ever worked a retail checkout will attest that barcodes do not always scan. An unusually shaped of an item (like on a bag of bread rolls from a bakery), or water or dirt on the label, all prevent bar codes from scanning. This forces manual entry of the product number, which is time-consuming and prone to error.

RFID will improve the point-of-sale accuracy, and retailers believe that the added ease of scanning will increase customer acceptance to use self-check-out lines instead of cashier-attended ones.

• Customer Service Desk

With serial numbers included on the RFID tag of every item sold, retailers can be sure that the item being returned is indeed the exact item that was purchased. What’s of added benefit is the retailer knows exactly what price the customer paid even if the customer doesn’t have the receipt. It is also useful for warrantees, rebates, and keeping services history.

Store Doors

As in the industrial environment, various portals can be RFID enabled:

• Dock doors

RFID-enabled dock doors at retail locations are very similar to those in industrial locations. As the doors are most typically used for inbound receiving, directionality can be assumed. There may be a dedicated outbound trailer used for returns. During holidays, it is not uncommon to use trailers for storage of fast-moving seasonal items.

• Perimeter doors

Perimeter doors are any doors that may be used for entry to or exit from the building. Sometimes perimeter doors are used for receiving purposes. Bakery goods, parcels, and even pallets may come in through these doors. These doors are normally configured as receiving doors, but are also used for security.

RFID-tagged goods should not be traveling into the read field of the perimeter door unless the products have passed through the point-of-sale system. Eventually, RFID tags will replace electronic article surveillance (EAS) systems. There are companies offering RFID readers that are integrated with EAS. The cost of these units is slightly more than standard EAS systems.

• Other doors

A retail store has a number of other portals inside the building that may be RFID-enabled, such as impact doors between the backroom and the retail floor. Doors between departments such as the meat department and deli, or the doors between the cold freezer and chilled icebox can also be RFID-enabled.

These portals must be carefully designed due to the variety of ways product may be traveling through them. For example a case may be hand-carried, or carried on a push cart or in a shopping cart. Directionality is very important for these portals and cannot be assumed. The objective of these portals is to determine where the products are stocked.

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Louis Sirico is the Founder and President of IndustryWizards.com. For more information on RFID technology, go to www.rfid.net