barcode and rfid fundamentals

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FFFFFundamentals of Aundamentals of Aundamentals of Aundamentals of Aundamentals of Automated Data Collectionutomated Data Collectionutomated Data Collectionutomated Data Collectionutomated Data CollectionUsing Bar Code and RFIDUsing Bar Code and RFIDUsing Bar Code and RFIDUsing Bar Code and RFIDUsing Bar Code and RFID

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years experience in solving business process problems with bar code and RFID.

1) Intr1) Intr1) Intr1) Intr1) Introductionoductionoductionoductionoduction

The first commercial use of the UPC bar code was at a grocery store in Ohio in 1973. The package scanned was a pack of

gum. Today we take the technology very much for granted but without bar codes

and bar code scanning technology, life would be very different.

Imagine what FedEx and UPS would be without bar codes. Imagine how long it

would take to check out at the grocery if every item had to be keyed in by hand.

The list goes on - bar code technology in manufacturing, distribution, transportation

and healthcare reduces the amount of time needed to get products to stores and

hospitals.

UPC Barcode


The three major benefits of bar code data collection include saving timesaving timesaving timesaving timesaving time,

reducing costsreducing costsreducing costsreducing costsreducing costs and increasing princreasing princreasing princreasing princreasing productivityoductivityoductivityoductivityoductivity. Time savings accrue through

the elimination of hand written data. Hand written data is inherently

slow and error-prone. A bar code scan is accurate to within 1 error per 1

million characters scanned. Cost reductions automatically flow from

time savings. If a worker can process 10 orders per hour manually,

another worker can process 50 orders or more via bar code scans. The

same is true for productivity gains - a worker who can produce more

results in less time is more productive.

The purpose of this book is to explain the fundamentals of bar code - how it works, how it is used, and how it integrates to

the world around us. In addition there will be an overview of RFID (Radio Frequency Identification) as it relates to

automated data collection.

Barcode & RFIDBarcode & RFIDBarcode & RFIDBarcode & RFIDBarcode & RFID•Save time•Save time•Save time•Save time•Save time•R•R•R•R•Reduce costeduce costeduce costeduce costeduce cost•Increase pr•Increase pr•Increase pr•Increase pr•Increase productivityoductivityoductivityoductivityoductivity


2) Symbology2) Symbology2) Symbology2) Symbology2) Symbology

A bar code symbol is made up of alternating lines and spaces. Combining these bars and spaces in specific

ways is similar to using Morse code. Using Morse code to spell out SOS uses 3 dots (...) then 3 dashes (—

) and then three dots again (...). A bar code is a “machine readable“machine readable“machine readable“machine readable“machine readable

symbol”symbol”symbol”symbol”symbol” meaning that it can be decoded (turned back into number

and letters) by any of several types of scanner. The bars and spaces

are analogous to the dots and dashes.

Using only bars and spaces, a bar code can represent numbers or

numbers and letters. In fact the entire ASCII character set can be

represented in bar code. When scanned by a laser scanner or imager

the bar code returns a signal pattern that is then interpreted by the

bar code reader; turning the symbol back into numbers and letters.

Using bar code almost any item can be identified - part numbers, location IDs, packing

slips, shipping documents, driver licenses - the list is endless.

A “linear“linear“linear“linear“linear””””” bar code is one dimensional; that is, the information is the same whether

you scan across the top, bottom or through the center. There are also 2 dimensional bar codes which

included “stack“stack“stack“stack“stacked”ed”ed”ed”ed” (many 1D codes stacked together) and “matrix”“matrix”“matrix”“matrix”“matrix” (a series of dots or lines).

Linear code

Stacked code

Matrix code

ASCIIASCIIASCIIASCIIASCIICharactersCharactersCharactersCharactersCharacters

http://www.cs.utk.edu/~pham/ascii.html


RFID (Radio Frequency Identification) also represents a ‘type’ of bar code which we will cover in more detail in a separate

section. The kThe kThe kThe kThe key to a bar code that is easy to scan is contained within the specifications for that symbologyey to a bar code that is easy to scan is contained within the specifications for that symbologyey to a bar code that is easy to scan is contained within the specifications for that symbologyey to a bar code that is easy to scan is contained within the specifications for that symbologyey to a bar code that is easy to scan is contained within the specifications for that symbology..... Bar code

specifications are the rules on how the bar code is to be produced. Those rules include a few terms we must define.

The “The “The “The “The “XXXXX” dimension” dimension” dimension” dimension” dimension - not science fiction but the width in “mils” (thousandths of an

inch) of the narrowest bar. So you will hear of a bar code referred to as 20 mil or 40

mil code; again that measurement is the width of any of the narrow bars in the printed

symbol. The X dimension is important for two reasons - 1) the wider the X dimension

the larger the overall symbol will be when printed. A bar code containing 12

characters will be smaller if the X dimension is 10 mil than if it is 60 mil and 2) the

larger the X dimension the farther away the bar code can be scanned.

The “N RThe “N RThe “N RThe “N RThe “N Ratioatioatioatioatio””””” - the N ratio compares the width of the narrow bar (X dimension) with the width of the wide bar. The

ratio will usually be 2 times, 2.5 times or 3 times the X dimension or, said another way, a 10 mil narrow bar will have a 20

mil, 25 mil or 30 mil wide bar. Again this is important for the same two reasons, 1) the larger the N ratio the larger the

printed symbol will be and 2) the larger the N ratio the easier the bar code will be to scan from a distance as the wider bar

provides a stronger signal when scanned.

The Quiet ZonesThe Quiet ZonesThe Quiet ZonesThe Quiet ZonesThe Quiet Zones - are the blank white areas on either end of a bar code symbol. These are important

because if the symbol is printed to close to the edge of a label the bar code scanner may not be able to

pick up where that symbol begins or ends. Typically a quiet zone is defined as being 10X or 10 times

the X dimension.


A device called a bar code verifier is basically a scanner with a

small integrated computer; when you scan bar code symbols

with a verifier it compares what it sees with the built in

specifications for that symbol and returns a letter grade. A, B

and C are acceptable, D or F are not.

Code 39 is used in many manufacturing operations including

the automotive industry; Code 128 encodes information

differently and allows more information to be compressed in

the same space as a larger Code 39 bar code. UPC is used in

retail; I2of5 is called Case Code and is often printed on corrugated

boxes. There are many other symbologies as well.


3) P3) P3) P3) P3) Printersrintersrintersrintersrinters

The good news is that any type of printer can be made to print bar code symbols.

The bad news is that any type of printer can be made to print bar code symbols. This

is not gibberish; each type of printer has strengths and weaknesses when it comes to

printing bar codes.

Desktop laser and inkjet printers can be used to print shipping labels - both Fedex and

UPS offer online label printing that includes the shipping bar code. PC software is

available to format and print bar coded labels and even to integrate label printing into

other corporate software. Desktop printers are often used to print shipping tickets or

pick tickets and can incorporate bar code symbols into these documents.

The downside of desktop printers is that they are usually not rugged enough to print

high volumes of labels. Additionally the labels you can run through a desktop printer

are not very durable; they don’t have the strength of adhesive to stick to corrugated

boxes and the print can be damaged fairly easily.

Dedicated bar code printers are thermal thermal thermal thermal thermal in nature; that is, they use a print head that becomes hot.

There are two variations - thermal directthermal directthermal directthermal directthermal direct uses a hot print head to ‘burn’ the image into a coated paper

stock. Heating this coating turns it black thereby producing an image. Thermal transferThermal transferThermal transferThermal transferThermal transfer uses a similar


hot print head but also uses a ribbon. The ribbon is melted onto

plain paper labels to produce an image. The labels and ribbons

are referred to as label ‘media’ and are a consumable that must be

replaced from time to time.

Thermal direct is cheaper because there is no ribbon but the label

material is still sensitive to heat and can yellow with time.

Thermal direct is best for labels that will be used within a six

month window of printing. Thermal transfer is more expensive

due to the ribbon but the labels will not change over time and are

not sensitive to heat.

Dedicated thermal bar code printers are also highly durable and

designed to be used under dirty and rough conditions. There are

also portable versions of these types of printers used for receipt

and ticket printing at venues such as outdoor events.

The shortcoming of this type of printer is the greater expense of consumable supplies and the limited print widths

available. Print width on bar code printers is usually 4 inches or 6 inches and the length of the label is

limited only by the length of the roll of bar code media.


Bar code printers can be set up to print in “batch” mode or “on-demand” mode. Batch mode is used to produce a run of

labels ahead of time that will be used to label products. The information encoded on the label typically comes from the PC

itself or possibly from a data source such as a WMS or ERP program. These labels can have multiple bar code symbols that

may include part number, lot number, serial number, and/or a date code.

On-demand printing is utilized to print a bar code label at a specific time and containing specific information. An example

of this is a printer programmed to print a packing label when a manufactured unit comes to the end of the production line.

Bar Code Media is simply another term for the labels, ribbons and tags used in a bar code printer. As an example, Avery

makes a popular address label, the 5160, used to

create mailing labels for letters. If you printed bar

code on these labels they would most likely scan

well. However if you tried to label a batch of boxes

they would eventually peel off as the adhesive is not

that strong.

Labels made for bar code printers typically come in

rolls or in long ‘fan folds’. The most common size is

a 4" by 6" shipping label. The

adhesive on dedicated bar code

media is much more ‘aggressive’

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meaning it will stick on many materials and not come off easily.

There are also specialized label adhesives for use in food

preparation and freezing (frozen food plants), adhesive that can be

removed easily (post-it note adhesive) and others.

Ribbons used in Thermal Transfer bar code printers are usually

made of a plastic film coated with carbon. Passing between the

thermal print head and the label stock, the image is ‘melted’ onto

the paper and is very difficult to scratch or remove. The ribbon in

a thermal transfer printer is a ‘one shot’ roll and cannot be reused.

Print heads gradually wear out due to the fact that the moving

labels and ribbons are in direct contact with the print head.

Purchasers of bar code printers should investigate the print head

warranty from the manufacturer to see if they allow the use of

‘foreign’ media without affecting the warranty coverage.


4) Scanners & R4) Scanners & R4) Scanners & R4) Scanners & R4) Scanners & Readerseaderseaderseaderseaders

The terms “scanner” and “reader” are often interchanged;

basically anything that can decode a bar code and change

it back into numbers and letters is a “scanner”. Anything

that can accept that decoded information is a “reader” .

For example, the omni-directional laser at your grocery

checkout is a scanner; the cash register is a reader.

For most of us, that particular scanner at the check out is

the one we’re most familiar with. It uses a low power

diode laser to produce a dot of red light. That red dot is

reflected against a spinning, faceted mirror to produce a

pattern of lines. When those lines cross the UPC bar

code symbol on a package of coffee a signal is reflected back to a photo eye inside the scanner itself.

That signal is decoded back into numbers and letters and sent up to the cash register. An important point here is that the

scanning replaces a human being having to type or key those numbers into the cash register - this is the fundamental benefitof bar code; replacing slow human typing or hand writing with fast electronic scanning. That

replacement speeds up check out (or picking orders in a warehouse) and reduces the chance of error (a

human will make a mistake keying once in every 300 characters typed).


Scanners typically use either a laser or an imager to “look” at the bar code. A hand held laser scanner (again something

most of us have seen at a local retail checkout; even brides-to-be are given a hand held terminal to scan items into their

bridal registry) uses a laser diode to produce a dot of light and a mirror flips the dot back and forth so fast that it appears to

the human eye as a solid line. These laser scanners flip the dot back and forth across the bar code symbol several hundred

times a second. There are specialized “fixed scanners” usually attached permanently to moving conveyor systems that can

scan up to 10,000 times per second and are used to capture bar code reads on items in motion on the conveyor.

An “imager” is related to digital camera. A solid state CCD (charge

coupled device) takes a picture of the bar code symbol; software inside

the device decodes it back into numbers and letters.

A bar code reader can take many forms. The cash register mentioned

before is a form of reader. An automated time clock at a factory or

business is a reader. A PC with a scanner attached is a reader. A hand

held “gun” like the ones used to check inventory at the grocery is a

combined reader AND scanner (which is what often causes the

confusion in terms).

In manufacturing there may be a fixed terminal (reader) attached to a fork lift which directs the driver

to pick items or put away items and scan the item and location as they work. The scanner is typically

a “gun” form factor attached to the reader by a stretch cord. The scanner in this instance may be a

Solid State Imager


long range scanner capable of scanning bar codes from a great distance from the bar

code label.

Hand held terminals today have the built in power of a regular PC usually running

Windows Mobile software; able to run very sophisticated programs. Additionally

there are programs running on mobile phones that

turn the built in digital camera into a bar code

reader.

Whatever its form, a bar code reader is designed

to run software that automatically collects data as

the worker moves through their tasks. The

program is related to what the company does and

what the particular worker is doing. For example, a worker checking in parts

shipments will be updating the companies inventory by scanning the items as they are

checked in.

Prior to using a scanning system, someone would have to print a bill of lading and go

over every package by hand, make a manual entry of some kind, and then later key their manual

entries into a computer terminal or PC. The actual inventory of what was on hand would be

inaccurate for the length of time it took to hand count and key in the information. Annual physical

Forklift mounted reader

Handheld reader with scanner


inventory involved people with clipboards, markers and

sticky labels going through the entire physical plant hand

writing as they went.

A worker on the production line might scan bar codes to

indicate how many assemblies they had created or how

many items they had picked. Some companies will install

scanners attached to their time & attendance systems and

have workers scan in and out of the job.

A fully automated operation will use bar code to receive,

manufacture, put away, pick, ship, and inventory.

Hand held and vehicle mounted readers typically communicate wirelessly via a wi-fi network much like a wi-fi hot spot at a

restaurant or store. This allows the readers to update the company software in real time giving a much more accurate

picture of what is happening within their processes.


5) Wireless Networking and WL5) Wireless Networking and WL5) Wireless Networking and WL5) Wireless Networking and WL5) Wireless Networking and WLAN used in Data CollectionAN used in Data CollectionAN used in Data CollectionAN used in Data CollectionAN used in Data Collection

Once a mysterious area familiar only to the military and ham radio operators, wireless communication is commonplace

today. Not that we necessarily understand it any better but manufacturers of laptops and cell phones have worked hard to

make wireless networking much easier to use.

The wireless ‘hot spot’ your laptop connects to at Starbucks is simply

a way to eliminate the cable plugged into a port on the computer.

Wi-Fi, as it’s sometimes called, stands for “wireless fidelity”; a

throwback to when stereo music was called High Fidelity.

As it relates to bar code data collection, manufacturers and

distribution operations deploy such wireless networks in their

facilities thereby extending the computer network through large

buildings or even groups of buildings.

The hand held and vehicle mounted terminals used to track

inventory or shipping have basically the same radio setup as your

laptop computer which allows information on what is happening in the facility to be updated in real

time. Prior to the wide spread of Wi-Fi, wireless networking was limited to very complicated

installations requiring large amounts of specialized equipment.



Today’s wireless installations carry voice and data and

allow for very sophisticated communications to take

place. In addition to data collection and walkie-

talkie (push to talk) networking, systems may even be

able to communicate with RFID tags to provide real

time location (RTLS) of people, parts or processes.

Care must be taken when installing Wi-Fi in a

manufacturing or distribution facility. Since radio

waves are reflected from certain surfaces and

absorbed by others, an professional experienced at

how radio works in these varying environments is

needed to guarantee radio coverage. In addition,

wireless networking has the potential to open your

network to hackers and phishers looking to steal

information. Additional care must be taken to add

safeguards to the wireless network to prevent these

‘invasions’.

A WLWLWLWLWLAN AN AN AN AN or Wide Area Local Access Network uses cell phone technology to gather and send data. This

technology is used most often in Mobility applications such as store delivery.

Access Points providing Wi-Fi Coverage


6) RFID basics6) RFID basics6) RFID basics6) RFID basics6) RFID basics

An RFID tag is analogous to a bar code label in that they both contain

encoded information. But a bar code always contains the same

information whenever it is scanned. An RFID (Radio Frequency

Identification) tag is a tiny integrated circuit with a tiny antenna

attached that usually encodes a unique number or bit of information

(called ‘static information’) or it may be able to change the information

contained in the chip (read/write tag).

The concept of RFID is that, in place of a bar

code scanner (laser or imager), an

interrogator (a type of radio that serves as the scanner and reader) fires a radio signal in the

direction of the tag via an antenna. Depending on the type of tag the radio signal strikes the

RFID tag and causes it to “respond” to the by sending back its information which is captured by

the interrogator.

Passive Tags have no internal power but use the energy of the interrogator radio to flash back a

response basically by reflecting the power of the interrogator. An ActiveTag contains a battery that allows the signal to transmit further increasing

the distance that the tag can be read.RFID Reader

Assorted RFID Tags


A passive tag may only read from a distance of a few inches to a

foot. An active tag may be able to transmit its information for

several yards. An active tag is also more likely to be programmable,

meaning that the information contained in the tag can be changed

perhaps to reflect it’s location or something that has changed such as

a step in a manufacturing process.

Problems with RFID tags can make them difficult to implement.

Because radio waves reflect much as light waves do, the signal from

an interrogator may reflect in the wrong direction causing the tag to

be missed. RFID-tagged items made from metal may also block the

tag from being read. In fact there are many materials - water

content, heavy paper, etc - that can affect the readability of an RFID

tag.

Applications of RFID technology are best suited to places where there is no one attending to the scanning such as tracking

packages traveling down a conveyor line. Some companies have placed RFID tags on finished goods and placed

interrogators on either side of a dock door so that the tag is read as it is placed on the truck thereby verifying the load.

RFID installations are still somewhat of an art and require experienced integrators who understand the

process of placing interrogators and antennas as well as understanding how to choose the proper RFID

tag technology.

Active RFID Tags



7) Applications T7) Applications T7) Applications T7) Applications T7) Applications Typically using Bar Code or RFID Typically using Bar Code or RFID Typically using Bar Code or RFID Typically using Bar Code or RFID Typically using Bar Code or RFID Technologyechnologyechnologyechnologyechnology

RRRRReceiving eceiving eceiving eceiving eceiving - the process of receiving raw materials in a manufacturing

facility or receiving finished goods at a distribution center or store.

This can be a challenging application for bar code. There are three

“if” conditions that must be met before this can work. IF your

suppliers bar code the items they ship to you and IF that bar code has

information your system can use (as opposed to it being THEIR

shipping label) and IF there is a way to compare those items against

orders then it may be possible to receive automatically using bar

code.

If items are not bar coded when they come off the truck, it may be

feasible to label them before putting them into raw goods inventory -

though this adds an additional step in the work process. It can also

be a problem if your facility uses the same dock doors for receiving

and shipping; can your programs differentiate between shipping and

receiving?

Receiving applications typically include a wireless network, hand held terminals, bar code printers, and

an integrated software application.

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Manufacturing - the process of combining raw materials

and/or components into a finished product (sometimes

referred to as ‘finished goods’) and WIP (Work inProcess) - the process of tracking an item through

manufacturing for the purpose of scheduling or tracking

the amount of time used in each step.

Knowing the exact location of an item as it is

manufactured can be a powerful Customer Service tool.

By bar coding the steps in the manufacturing process and

scanning the items as they are built, a real time picture of

the overall operation is possible. Customers looking for

updates can be given realistic time-frames for when their

order will be ready for shipment.

Manufacturing applications typically include a wireless

network, bar code labeling of work orders, fixed or

portable readers, and, for some applications, RFID tags

and readers.


Time & Attendance - the process of tracking the work time of employees.

Most facilities use an employee identification some type. Time & Attendance systems usually use a fixed reader with a bar

code scanner, RFID reader, or Mag Stripe (like on your credit card) reader.

Inventory - the process of putting finished goods into storage locations

for use in filling orders. There are three types of inventory - raw goods

or component inventory, work-in-process inventory, and finished goods

inventory.

Knowing what you have to work with is a key to success in

manufacturing and distribution. A bar code inventory system links an

item number with a location by scanning both the item and the

location. Locations may vary widely; from shelf labeling in a retail

store to large reflective bar code labels used to identify racking in a

warehouse. Using bar coded inventory allows a company to have a

better idea of what they have on hand; replacing or reducing the

practice of annual inventories and cycle counting.

Inventory applications typically use a wireless network, bar code printers or pre-printed labels,

specialized location labels for identifying specific warehouse locations, and hand held or vehicle

mounted terminals.

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Picking/Shipping - the process of filling an

order from inventory and sending it to its

final location.

Orders entered by sales and administration

cannot be completed until they are picked

and shipped. Shipping an order usually is

the trigger for an invoice to be generated

for that order so it is important that it is

done accurately. Inaccurate shipments can

be costly for an operation; a mis-shipment

can cause delays in payment and

additional cost for correcting the mistake.

By scanning bar codes as a shipment is

picked, inventory can be kept accurate and

orders can be verified.



Delivery/Mobile Applications - a class of applications directing

and tracking mobile workers as they perform daily tasks.

The list of mobile applications is long - route sales, route

accounting, proof-of-delivery, signature capture, service

dispatching, service accounting and service billing, GPS

tracking, turn-by-turn instructions and many others.

Mobile applications typically use a WLAN or wide-area local

area network; which in simpler terms means using cell phones

for communication. Portable terminals used in mobile

applications now combine bar code scanning, digital camera,

GPS tracking, signature capture and Windows Mobile software

into a single unit. There may also be battery-operated,

portable label or ticket printers for printing receipts, bills,

tickets, or other documents.



8) Conclusion8) Conclusion8) Conclusion8) Conclusion8) Conclusion

The application of bar code and RFID technology has dramatically changed the way business is done. Gone are the days of

hand tagging groceries and re-tagging them when the price changes.

While bar code usage is wide spread, there are still thousands of application possibilities. Wherever someone is hand

writing information or hand keying that information into a computer, there is room for automation. Automated Data

Collection using bar code and/or RFID can reduce the cost of information, speed the movement of information, and

increase the accuracy of information gathered - all resulting in increased productivity and reduced cost.

The key to this improvement can be found in a well designed system. ADC Integrated Systems has over 150 man years

experience with all aspects of AIDC and RFID. We can help you with system specifications, wireless networking, equipment

selection, installation, training and support. We offer a no-obligation review of your particular application.

Contact us via our website - www.adcisi.com -or via email at [email protected] call 901-327-9946.


Copyright 2009, ADC Integrated Systems, Inc.2701 Union Avenue Extended, Suite 504

Memphis, Tennessee 38112901-327-9946

barcode and rfid fundamentals

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