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RFID
Update A lot has
happened in RFID since the book was published. Though universally accepted standards
are not yet in place, GTAG and EPC have
been getting a lot of attention. EPC (electronic product code) is sort
of the RFID version of the UPC barcode. It is intended to be used to
identify specific products, as well as cases and pallets. GTAG (global
tag) is an international standard that can be used for more general
asset tracking. Until recently, RFID readers and the related software
were
designed to work with RFID tags from a specific manufacturer. In this
respect, these were essentially closed proprietary systems. The adoption
of data standards as well as technical standards is critically important
to extend this technology beyond individual stand-alone systems.
Wal-Mart
announced they would require their top 100 suppliers provide RFID on
cases and pallets. The Department of Defense followed with it’s own RFID
program as did Target. All these RFID initiatives are focusing on the
EPC standard (or variations of the EPC standard).
In 2003,
Gillette announced that they would start testing "smart shelves" in
selected stores, and then promptly put the project on hold after
privacy
concerns were voiced. As the name would imply, a smart shelf is a
shelf that has capabilities beyond just preventing the product from
falling on the floor. In this instance, the shelf has an integrated RFID
reader. Each unit on the shelf will have an RFID tag, allowing the
reader to track inventory levels. The purpose of the smart shelf is to
support replenishment, ensuring the shelf is never empty.
All this
activity (especially the
Wal-Mart
announcement) seems to have energized the RFID industry and
convinced the makers of portable data collection devices to get on the
ball and start integrating RFID readers into the portable devices. It
seems as though all of the major suppliers of hand-held portable
industrial computers now have at least one model with an integrated RFID
reader. For the most part, these basically consist of an RFID antenna
attached to one of their current models of portable terminals. .
This provided me the opportunity to start asking some tough questions related
to the technology. Most importantly, I inquired about problems related
to applications where selective scanning was necessary. Currently,
the majority of RFID use in warehouses and manufacturing facilities is
related to large pallets or containers moving into and out of trucks or
through various parts of the facility. There is generally only one RFID
tag per pallet or container and the scanning occurs when the the pallet
or container passes through a scan tunnel ( a scan tunnel is really just
a large frame with RF antennas mounted on it). This provides a
controlled selective read of the loads as they pass through the scan
tunnel.
But now,
with RFID expanding to hand-held devices, how do you make sure you are
reading only the tag you intended to read? I talked to one vendor that
was demonstrating the reader with both a palletized load and an
individual case. I immediately noticed he had strategically placed the
single case well away from the pallet with the other RFID tags. So I
asked him, what if this case was right next to this pallet, could I
still just scan the one case? He answered "no". The problem was that
even though this RFID reader was designed as a directional reader, it
was also designed to read tags from a distance exceeding six feet. Which
means, unless you maintain a significant clear area around the
individual loads you intent to read, you will risk unintentionally
reading other tags. Another hand-held device I looked at did not use a
directional reader, which ultimately results in the device reading any
tag within a three to four foot spherical area around the reader
regardless of the direction the user thinks he is pointing the device.
The problem
here is RFID is being demonstrated in traditional bar code applications.
It simply makes no sense to use RFID in an application where bar codes
work better and are cheaper. Unfortunately, it is yet unclear as to
where RFID will find a home in inventory transactional processes.
Because of this, hand-held device manufacturers are not sure how to
design the devices. Should they be directional? If so, how tight should
the directional capabilities be? What will the desired read distances
be? From my perspective, using RFID with hand-held devices for inventory
transactional processes in the warehouse and on the shop floor is still
in the experimental stage. The technological capabilities are there, but
we are not yet sure what the application is. It's clear that the
manufacturers of the hand-held devices shared this view as their RFID
devices were really just one of their portable bar-code computers with
an RFID antenna added to it. If you think I was critical of hand-held
computers before, you can only imagine my thoughts as I picked up these RFID devices that were almost twice the size and weight of the original
hand-held device.
So let's go
back to the more popular scan-tunnel applications. These applications
are currently in place in many operations and are well beyond the
experimental stages. The most common application involves a single RFID
tag that is attached to a reusable pallet or container. The tag contains
a unique code that corresponds to data maintained in the company's
computer system. This data describes the load (SKU numbers, quantities,
order numbers, etc). When used in receiving, the data was likely
received before hand in the form of an advance shipment notification (ASN).
When the load comes off of the truck and passes through the scan tunnel
(usually mounted just inside the dock area), the RFID antenna reads the
signal and completes a transaction receiving the contents into stock. On
the outbound side the process would be reversed. Within a manufacturing
environment, passing through the scan tunnels may update operational
status of the associated production order or may just track physical
location within the facility.
This is a
useful and relatively simple application of RFID technology. In the
design of this type of system, you need to make sure you provide
programming to deal with the possibility that something may pass through
the scan tunnel multiple times. For example, a lift truck operator
loading a trailer may need to unload and then reload the trailer if a
problem occurs during the loading. Or, depending on the position of the
scan tunnel, the lift truck operator may move back and forth to adjust
loads on the back of the truck. There are also some technical challenges
when more than one scan tunnel is used in the same area (such as
side-by-side dock doors).
One of the
big advantages of RFID being promoted is the ability to read RFID tags
through other objects. This brings up the scenario where an RFID tag is
placed on every carton or every individual item. When a palletized load
passes through the scan tunnel, the reader will register all of the tags
on the pallet, thereby providing a potentially 100% check of the entire
shipment almost instantaneously. I'll admit this sounds wonderful from
both an accuracy and a productivity perspective, but, as you may have
suspected, I have some concerns. Since RF signals have problems with
some materials (metals, some liquids, lead-lined underwear), I think we
can assume that this application will be limited to tracking of products
that do not block or otherwise interfere with the RF signals. This is an
area to watch closely to see if tag manufacturers are able to produce
low-cost tags that can minimize this interference.
And
remember all the hype about the capabilities of RFID tags to have data
written to them (added or changed) at various points in the supply
chain. Well, the capabilities are there, but none of the pending
standards or touted applications currently in the works are utilizing
this capability. Nor are they taking advantage of the ability to store
more data in an RFID tag than they could in a 1D bar code. In fact, the
largest benefits to the pending EPC initiative are actually more related
to the architecture and standards for storing and sharing information
between trading partners than they are to the functionality of RFID
itself. This information depository known as the EPC network has very
little to do with RFID technology. In fact, the EPC network could
essentially run with bar codes as the input rather than RFID tags. Read
the EPC Misconceptions section (next) for more details and also check
out the New Definitions at the bottom of the page.
As a
general recommendation, RFID is not yet practical for most businesses
looking to automate their inventory related transactions. In the next
few years, standards will be finalized, hardware prices will drop,
software will become more readily available, and, more importantly, the
bugs will be worked out of these systems. Let the Wal-marts and other
big companies pay the initial development costs and bear the brunt of
the pain related to early adoption. Meanwhile, bar codes remain the most
practical option.
You may also want to check out my other
RFID Update at InventoryOps.com
(my primary website) for more information on
RFID, Wal-Mart,
EPC, Privacy Concerns and More.
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New
Definitions
EPC—electronic product code. EPC is the RFID
version of the UPC barcode. EPC is intended to be used for specific product
identification. However, EPC goes beyond UPC by not only identifying the
product as an SKU, but also providing access to additional data (via the
EPC Network) about
the origin and history of the specific units. The EPC tag itself
identifies the manufacturer, product, version, and serial number. It's
the serial number that takes EPC to the next level. This is the key to
data related to specific lots/batches as well as potentially tracking
the specific unit's history as it moves through the supply chain. This
data is stored somewhere else (the internet or other network) but a
standardized architecture allows you to access the data much like you
would access a web page (though this would be happening automatically
behind the scenes).
EPC Network—an architecture similar
to the internet designed to store and allow access to data related to
EPC. For example, detailed item information such as description,
ingredients, size, weight, cost; manufacturing information about the
specific lot such as when and where it was produced and expiration
dates; and distribution information about where it has been including
addresses, dates and times. The data could be as detailed as including
environmental factors such as temperatures during manufacturing or
storage. This data flexibility is accomplished through the use of a new
computer language called Physical Markup Language (PML)
which is essentially a variation of the more commonly known Extensible
Markup Language (XML).
GTAG—global tag. GTAG is an international
RFID standard that can be used for general asset tracking.
Slap-and-ship—term used to describe
an approach to complying with customer requirements for physical
identification of shipped goods. Most recently, slap-an-ship has been
used to describe complying with RFID requirements (such as those from
Wal-Mart), however, it is also applicable to any compliance labeling
requirement (such as compliance bar code labels). Slap-and-ship implies
you are meeting the customer's requirement by applying the bar code
labels or RFID tags, but are not utilizing the technology internally.
Smart shelve—as the name would imply, a
smart shelf is a shelf that has capabilities beyond just preventing the
stored product from falling on the floor. In this instance, the shelf has an
integrated RFID reader. Each unit on the shelf will have an
RFID tag, allowing the reader to track inventory levels in real time.
Go to Inventory
Accuracy Glossary for additional related terminology.
Go to RFID Links
for links related to RFID technology.
Go to Tech Updates
for additional technology updates.
Go to InventoryOps.com's
RFID Update page
for additional RFID info.
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