cycle time calculation-unit_10_automatic_identification.pdf

7/27/2019 Cycle time calculation-unit_10_automatic_identification.pdf

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Unit 10 Automatic Identification

10.1 Unit Introduction10.2 Unit Objectives10.3 Overview of Automatic Identification Methods

10.4 Barcode Technology10.5 Two-Dimensional Bar Codes10.6 Radio Frequency Identification10.7 Other AIDC Technologies10.8 Case Study10.9 Unit Review10.10 Self Assessment10.11 Self Assessment Answers

10.1 Unit Introduct ion

Automatic identification and data capture (AIDC) is the use of technology toprovide direct data entry to a computer, or other micro-processor controlledsystem, without resorting to manual methods of data-entry. Data collection andretention has increasingly been automated to the point where AIDC systems canoperate without relying upon human operators for basic data identification andcapture. The following applications are regularly operated in AIDC mode:material handling, storage, sorting, order picking, kitting of parts for assembly;monitoring work order status, work-in-process, machine utilisation, workerattendance, and other measures of factory operation and performance.

KEYPOINTAutomatic identification and data capture (AIDC) is the use of technology toprovide direct data entry to a computer.END KEYPOINT

The alternative to AIDC is manual data collection and retention; this suffers fromhigher rates of error, greater requirements on time, and higher labour costs thanAIDC. This unit investigates AIDC with a primary emphasis on bar codetechnology and radio frequency identification (RFID). Other AIDC technologies,including magnetic stripes, optical character recognition, and machine vision

10.2 Unit Learning Objectives

After completing this unit you will be able to:

BULLET LISTIdentify the concept of Automatic Identification and Data Capture

Specify the types of barcode technology that can be identified


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Name the major barcode standard that informs the use of barcodes made bymost of contemporary industry

Outline the two basic types of two-dimensional barcodes

List advantages of Radio Frequency Identification (RFID) technology

Identify the principal elements of an RFID system

Explain how RFID middleware acts in the RFID system

List other AIDC technologiesENDLIST

10.3 Overview of Automatic Identification Methods

There are three specific components that comprise technologies for AutomaticIdentification and Data Capture (AIDC) (see Figure 10.1); these are:

NUMLISTData encoderdata must be coded into a machine-readable format compatibleto the requirements of AIDC. A label or tag containing the encoded data isattached to the item to be identified

Machine reader or scannerthis is used to read the encoded data, typicallyconverting it into the form of an electrical analogue signal

Data decoderthis transforms the electrical signal into digital data and finallyback into the original alphanumeric charactersENDLIST

KEYPOINTAIDC technologies consist of three principal technologies that are appliedsequentially; these are data encoding, machine reading, and data decoding.END KEYPOINT


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Figure 10.1: Data encoding, reading and decoding using bar codes

AIDC technologies can be categorised into the six types outlined in Table 10.1.

Table 10.1: Categories of AIDC technologyTechnology Description

Optical

l

Uses an optical scanner for the reading of high-contrastgraphical symbols. Can include one- and two-dimensionalbarcodes, optical character recognition, and machine vision.

Electromagnetic Best known application of these technologies is radiofrequency identification (RFID), which is substantiallyencroaching upon optical technology markets, such asbarcode usage. RFID technology deploys a tag capable ofholding significantly more data than traditional barcodes.

Magnetic Data is encoded magnetically, either by means of a magneticstrip (for example as used in credit cards), or by means ofmagnetic ink character recognition (used in the bankingindustry for cheque processing).

Smart card Cards with embedded microchips that are capable of holdinglarge amounts of information; also known as chip cards, orintegrated circuit cards.

Touch techniques These technologies include touch screens and button


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memory.

Biometric Technologies used to identify humans, or to interpret vocalcommands of humans. They include voice recognition,fingerprint analysis, and retinal eye scans.

KEYPOINTAIDC can be categorised into optical, electromagnetic, magnetic, smart card,

touch technique, and biometric technology types.END KEYPOINT

AIDC technologies may be applied in receiving, shipping, order picking, finishedgoods storage, manufacturing processing, work-in-process storage, assembly,and sorting. Some techniques of AIDC are semi-automatic, in that they stillrequire personnel to operate some of the identification equipment in theapplication. Other applications may be fully automated.

AIDC provides high levels of data accuracy, in real time, and at reduced labourcosts. The error rate of barcode technology is approximately 10,000 times lower

than in manual keyboard data entry. While other technology cannot achieve thesame levels of accuracy as barcode technology, they are still significantly betterthan manual techniques, where we are reliant upon human workers to make thedata entry. A second reason for the success of AIDC techniques is the reductionof time required for the input of data: the speed of data entry for handwrittendocuments is approximately 5-7 characters per second, andat best10-15characters per second for keyboard entry. AIDC methods can accomplishhundreds of characters per second.

KEYPOINTAIDC provides high levels of data accuracy in real time, and at reduced labour

costs.END KEYPOINT

Errors, however, can occur with AIDC technology; and these are measured bytwo parameters:

NUMLIST


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First Read Rate (FRR)the probability of a successful, or correct, reading by thescanner in its initial attempt.

Substitution Error Rate (SER)the probability or frequency with which thescanner incorrectly reads the encoded character as some other character. The

expected number of errors is given by:

)(. nSERExp

whereExp. Is the expected number of errors; SER is the Substitution Error Rate;and n is the data set with that numbers of characters.ENDLIST

The aim of the system is, of course, to have a high FRR, and thus not require anSER reading.

KEYPOINTErrors with AIDC technology are measured by two parameters: First Read Rate,and the Substitution Error Rate.END KEYPOINT

10.4 Barcode Technology

There are two basic types of barcode technology, linear and two-dimensional.

KEYPOINT

Two types of barcode technology can be identified: linear barcode technology,and two-dimensional barcode technology.END KEYPOINT

Linear or one dimensional bar code technology is the most widely used AIDCtechnique. There are two forms of linear barcode: width-modulated barcodes,and height-modulated barcodes. These are outlined in some detail in Table 10.2.

Table 10.2: Linear barcode formsType DescriptionWidth-modulated barcode Used widely in retailing and manufacturing, the barcode consists of

bars and spaces of varying width, with the bars and spaces beingin highly-contrasting colours, such as black and white. The patternof bars and spaces is coded to represent numeric or alphanumericcharacters. This code is subsequently interpreted by a barcodereader; this reading action is done by scanning and decoding thesequence in which the bars fall.

The barcode reader itself consists of a scanner and decoder. Thescanner emits a beam of light that is either automatically ormanually swept over the barcode to be read, thus allowing thereader to sense light reflections from the barcode that


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distinguishes between bars and spaces. A photodetector covertsthe resultant reflections into an electrical signal, where spacesrepresent the signal, and bars represent its absence. Bar-width isthus converted into electrical signal duration. The decoderanalyses the pulse train to validate and interpret the correspondingdata.

Height-modulated barcode Niche-industry barcode technology, operative in the US Postalservice, where it is deployed for ZIP code identification. Thebarcode in question is distinguished by a series of evenly-spacedbars of varying height. Operative principles are similar to thoseoutlined for width-modulated barcodes.

KEYPOINTThere are two forms of linear, or one-dimensional, barcode: width-modulatedbarcodes, and height-modulated barcodes.END KEYPOINT

The growth and industrial acceptance of barcodes (width-modulated barcodes inparticular) occurred in the 1970s, when retailers started to rely upon thetechnology for product identification, and to aid storage management techniques.In 1973, the grocery industry adopted the Universal Product Code (UPC) as itsstandard for item identification. UPC uses a 12-digit barcode where six digitsidentify the manufacturer and five digits the product, and one digit acts as acheck character. Another major endorsement of this technology came from itsacceptance as the standard product identifier by the US Department of Defencein 1982, compelling its vendors to adopt the technology.

10.4.1. Bar Code Symbols

The barcode standard adopted by most major industries is a subset of Code 39,known as AIM USD-2 (Automatic Identification Manufacturers Uniform SymbolDescription-2). Code 39 uses a series of bars and spaces to representalphanumeric and other characters, where, in binary terms, the bars areequivalent to 1 and the spaces are equivalent to 0 (see Figure 10.2). Bars andspaces can differ in width by as much as 3 times their conventional size, whichhas a corresponding effect upon reading produced. However, the width-to-narrowratio, whatever it is set-to, must be consistent across the barcode to facilitateaccurate interpretation of the pulse train produced.


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Figure 10.2: Code 39

KEYPOINTMost major industries use a barcode standard that is based upon a subset ofCode 39, known as AIM USD-2.END KEYPOINT

The name Code 39 comes from the physical appearance of the barcode, whichconsists of nine elements (bars and spaces) used for each character, while threeof these elements are wide. It is the placement of the wide spaces and wide barsthat uniquely designates the character. Each code begins and ends with either awide or narrow bar. In addition to the character set in the barcode, there is also a

quiet-zone that precedes and succeeds the barcode; this ensures that thedecoder is not confused by the absence of bars and spaces in regions outside ofthe barcode field.

KEYPOINTBarcodes in Code 39 consist of an arrangement of nine bars and spaces, whichform a unique character for each arrangement; and a quiet-zone, consisting ofempty space, which both precedes and succeeds the barcode in its presentation.


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END KEYPOINT

10.4.2 Bar Code Readers

There are different types of barcode readers, generally classified as eithercontact or non-contact readers. These are outlined further in Table 10.3.

Table 10.3: Barcode reader typesType DescriptionContact readers Consist of hand-held devices, such as wands or light pens, which are

operated by moving the tip of the wand quickly past the barcode on theobject or document. They are contact devices because the wand orpen must touch the barcode surface, or be in very close proximity, foreffective reading. They can be mounted as well as hand-held, such thatthey form part of a keyboard entry terminal; in such situations thereader is stationary and the objects barcode is swept-past the deviceso that it may be read.

Portable reading units are also available, which makes them suitable tobe carried-around the factory or warehouse by a worker. These aretypically battery-powered and include a solid-state memory devicecapable of storing data acquired during operation. They may alsoinclude a keypad so that non-barcode data may be manually entered.

Non-contact readers These focus a light beam on the barcode to scan and decode thebarcode in the conventional way, but at a distance of from severalinches to several feet. They can be classified as fixed beam and movingbeam scanners.Fixed beam readers are stationary units that use a fixed beam of light.

They can be mounted beside a conveyor to scan items as they pass,and thus record what is being placed upon the conveyor. Typicalapplications occur in warehousing and material handling operations.

Moving beam readers use a highly focused beam of light to search forthe barcode upon an object. A particular scan is defined as a singlesweep of the light beam through an angular path specified by a rotatingmirror used to project the beam on to the object. Typically the mirrorrotates at very high scan ratesup to 1440 scans/sec; thus, when abarcode is located, it may be read more than once, permittingverification of the reading. Typical applications include being mountedalongside conveyors, just like fixed beam readers, or as portabledevices that the user points at objects, in the same manner as a pistol.Again these applications occur in warehousing and material handlingoperations.

KEYPOINT

Barcode readers may be classified as either contact or non-contact devices.END KEYPOINT

LEARNING ACTIVITY 10.1Visit www.youtube.com and look up videos that illustrate the design andoperation of various types of bar code equipment outlined in Table 10.1 andTable 10.3. Make a note of the manufacturers names. Visit the web site of themost common names and evaluate their product and service offerings.


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END LEARNING ACTIVITY 10.1

10.5 Two-Dimensional Bar Codes

Two-dimensional (2-D) barcode schemes were introduced in 1987, and havegrown into more than a dozen symbol classifications, with more expected to beproduced. 2-D barcodes can store greater amounts of data at higher areadensities than their one-dimensional counterparts; their disadvantage is therequirement for special scanning apparatuses to read the codes, and theassociated expense of purchasing such equipment.

KEYPOINTTwo-dimensional barcodes store greater amounts of data at higher areadensities than their one-dimensional counterparts.END KEYPOINT

The two basic types of 2-D barcodes are: stacked barcodes, and matrixsymbologies. These are outlined in some detail in Table 10.5.

Table 10.5: Two-dimensional barcode typesType Description

Stacked barcode Consists of multiple rows of conventional linear barcodes stacked on topof each other. The data density of stacked barcodes is typically five toseven times that of the linear barcode 39. Various stacking schemes maybe applied to achieve the build-up of barcodes one on top of the other,and still allow them to be read.Decoding in a stacked barcode is done by using a laser-type scanner thatreads the lines sequentially. Issues with barcode-reading include: keeping

track of the different rows during scanning; dealing with scanning swathsthat cross between rows; and detecting and correcting localised errors.

There can also be printing defects, similar to one-dimensional barcodes.Matrix barcode Consists of 2-D patterns of data cells that are usually square and are

coloured dark (usually black) or white. Introduced around 1990, they cancontain more data than stacked barcodes, and also have the potential forhigher data densities (up to 30 times more dense than code 39). Howeverthey are more complex than stacked barcodes, and they require moresophisticated printing and reading equipment.

The symbols must be produced and interpreted both horizontally andvertically, which is referred to as area symbologies. Recent advanceshave seen considerable improvements in data matrix readers, which areeasier to set up and use, as well as being more robust, and reliably

operating under a range of conditions.

KEYPOINTThe two basic types of 2-D barcodes are stacked barcodes, and matrixsymbologies.END KEYPOINT


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RFID reader. Figure 10.3 depicts a typical RFID tag, with microchip and capacitorset-up at the centre, while the antenna-coil encircles it.

Figure 10.3: Passive and Active RFID tags respectively

KEYPOINTAn RFID tag consists of an infrastructure that contains a microchip, capacitors,and antenna-coil. Depending on the tag type, it may or may not contain a battery.

END KEYPOINT

Each tag has a certain amount of internal memory where information about theobject is stored, such as its unique ID number, or in some cases more detaileddata including the date of manufacture, product composition, etc. Thecommunication process between the reader and tag is managed and controlledby one of several protocols, such as ISO 15693, ISO 18000-3, ISO 18000-6, andElectronic Product Code (EPC) for different radio frequencies. In addition,different types of anti-collision algorithms are defined as part of these protocolstandards, so that many tags presenting to one reader at the same time can besorted and individually selected.

Once the reader is on, it starts emitting a signal at a selected frequency. Anycorresponding tag in the vicinity of the reader will detect the signal and use theenergy from it to wake-up and supply operating power to its internal circuits.Once the tag has decoded the signal as valid, it replies with information to thereader thereby identifying the object. This information, called a notification, isthen sent to RFID middleware. To deal with huge volumes of data (ornotifications) from RFID tags, RFID middleware has been developed to act as abuffer between the RFID tag and the computing systems of the plant. RFIDmiddleware has the ability to handle data operations, such as filtering,aggregation, and enrichment etc., as well as ensuring that data is processed into

an appropriate format for application in the middleware. A reversecommunication from the middleware to the RFID tag is also possible, which iscalled commands. Commands for RFID readers may be reading or writingcommands which are emitted from the middleware based upon certainimplemented rules.

KEYPOINT


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A RFID system consists of a number of RFID tags, RFID middleware, and thesystems back-end computing systems.END KEYPOINT

10.6.2 RFID Tags

There are two types of RFID tag: Active tagsthat is, they contain and areindependently powered by a battery; Passive tags (or unpowered tags)whichrely on power drawn from the reader to be activated.

Active tags are larger, more expensive and, owing to the presence of the battery,have a limited life. Passive tags, on the other hand, are lighter, smaller, cheaperand have an unlimited life; however, they are inhibited by their relatively shortread ranges, the requirement for high-powered readers, and by the fact that theycan only be written to once (i.e. they are read-only). In contrast, active tags canuse greater variability in readers and can be read at significantly longer

distances, while they usually contain facilities to read and write a multiple numberof times.

KEYPOINTThere are two types of RFID tag: active tags, which are battery-powered; andpassive tags, which rely on power drawn from the reader to be activated.END KEYPOINT

There also exist hybrids called semi-passive tags that use small batteries tooperate the RFID chips circuitry, but rely on reader-power for communication.Table 10.6 summarizes some general aspects of RFID tag performance across arange of environments.

Table 10.6: RFID tag performanceFrequencies Low Frequency High Frequency Ultra-High

FrequencyMicrowave

General Long antennas,more expensive.Less prone tointerference frommetals and liquids.Largely installedbut will beovertaken by higher

frequencies.

Shorterantennas, lessexpensive thanlow freq. tags.

This frequencyhas the widestapplicationscope. Best

suited forapplications thatdo not requirelong rangereading of largeamounts of tags.

Smaller,Cheaper. Higherfrequency meansthese tags arepotentially morepowerful andhave greaterrange. More

susceptible tointerference bymetals andliquids. Differentfrequencies andpower allocatedby differentcountries.

Similar to ultra-high freq. butfaster read rates.Much moresusceptible tointerference bymetals andliquids. This

frequency band isshared by othertechnologies,includingbluetooth andmany other short-range radiodevices.


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StandardsSpecifications

ISO/IEC 18000-2 ISO/IEC 18000-3,AutoID HFclass1,ISO 14443,ISO 15693

ISO/IEC 18000-6AutoID class0,AutoID class 1

ISO/IEC 18000-4

Typical ReadRange (typicalvalues in metres)


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RAM (random access memory) that stores data accrued during transponderinterrogation and response

WORM (write once / read many memory) that is similar in functionality to RAM.ENDLIST

KEYPOINTThere are three different types of RFID memory: read only memory; randomaccess memory; and write once / read many memory.END KEYPOINT

LEARNING ACTIVITY 10.2Search the internet for videos, slides, articles and vendors for RFID technologyused in industry. Write a short note of your findings.END LEARNING ACTIVITY 10.2

10.6.4 RFID ReadersRFID readers communicate with the RFID tags via radio waves and passinformation to the backend computer system in digital form. Readers can beconfigured in many formats including handheld devices, portals, or they may beconveyor-mounted. The user can change or customise the readers operations tosuit a specific requirement by issuing commands through the RFID middleware.

The purpose of an RFID reader is not to store data; rather it transfers data to andfrom the RFID tags, though short-term data storage is still required. Theconfiguration information of a reader (e.g., the reader address, and configurationfor filtering) is stored consistently during the entire operation of the RFID reader.Furthermore, in some cases, data acquired from the tags needs to be stored forshort-term processing and forwarding to the middleware.


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Figure 10.4: RFID tags and reader/sensor

KEYPOINTRFID readers communicate with the RFID tags via radio waves and pass

information to the backend computer system in digital form.END KEYPOINT

When large numbers of RFID tags are presented to the RFID reader, dataprocessing utilities are required to capture the high-volume data flows that occur.A reader can either process the field data from the tags, or the command datafrom the middleware (e.g., read/write commands). Pre-processing (e.g., filteringand aggregation) is used to relieve the middleware from processing too manynotifications at any one time. Commands provided by the middleware (e.g.,invoking a write operation on a tag) need to be stored for a short while andtranslated into internal RFID reader commands.

10.6.5 RFID Middleware

RFID middleware acts as mediation between the RFID tag and the enterprisesystems back-end. It is responsible for handling notifications, such as filtering,aggregation, enrichment, etc., according to specific rules implemented in themiddleware.


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KEYPOINTRFID middleware acts as mediation between the RFID tag and the enterprisesystems back-end.END KEYPOINT

Data processing in the middleware is similar to pre-processing in the RFIDreader. Notifications that are irrelevant for the business process are filtered-outand faulty information is eliminated. The filtered notifications are then processedfurther to develop business events that are sent to enterprise computing back-end systems. This information can either be held locally in the middleware, orcome from external devices, which are connected to the middleware (e.g.,sensors, field databases, human user interfaces). Connections may also bedeveloped to external information systems so that supplementation of theexisting information by external sources can occur. For external informationsystems to operate successfully with RFID systems, automatic identificationinfrastructures are needed, such as the Object Naming Service (ONS) or the use

of external WWAI network nodes (see Figure 10.5).

Figure 10.5: RFID Middleware

KEYPOINTRFID middleware acts as an effective data-filter, and subsequently developsbusiness events from the processed data that are sent to enterprise computingback-end systems.END KEYPOINT


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10.7 Other AIDC technologies

Other AIDC technologies that may occasionally be used in automationenvironments are summarised in Table 10.7.

Table 10.7: Other AIDC technologiesTechnology Description

Magnetic Strips These strips are attached to products or containers in warehouseand factory settings, and are used for product identification. Themagnetic strip consists of a thin plastic film with small magneticparticles whose pole orientations are used to encode bits of dataonto the film. The plastic film is usually mounted onto a plastic card(such as a credit card), or paper ticket to provide a robustinfrastructure, and as means of automatic identification.Advantages include: the ability to hold large amounts of data, andthe ability to alter data held, if necessary.Disadvantages, from a manufacturing point-of-view, include: the

need to have the strip in contact with the scanning equipment forcorrect reading; the absence of shop-floor methods that canreadily encode data to magnetic strips; and the expense of thetechnology.

Optical CharacterRecognition

Here specially designed alphanumeric characters that are machinereadable by an optical reading device are deployed in factory andwarehouse applications. Optical character recognition is a 2-Dsymbology, and scanning involves interpretation of both thevertical and horizontal features of each character during decoding.

The use of hand-held operators, therefore, may require a certainlevel of skill on the part of human operators, to ensure thatcharacters are read correctly; often this requires multiple scans ofthe code.

The benefit of optical character recognition is that both machinesand humans can read the same text.Disadvantages include: the need for near-contact scanning; lowerscanning rates; and higher error rates compared to barcodescanning.

Machine vision Used principally for automated inspection tasks, machine visionread 2-D matrix symbols, such as data matrix, or stackedbarcodes. Applications of machine vision also include other typesof automatic identification problems, and these applications maygrow in number as the technology advances.

KEYPOINTOther AIDC technologies that may occasionally be used include: magnetic strips,optical character recognition, and machine vision technologies.END KEYPOINT


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10.8 Case Study

At its factory in Galway, Thermo King employees press a button to alertmanagement whenever parts need to be replenished, thereby preventing workstoppages and part overstocks.

Using AeroScout tags, the system is built onto the company's existing Wi-Fisystem and was integrated by IMEC Technologies. This year, the firm is also inthe process of expanding its usage of RFID at the Galway facility to include toasset tracking. The immediate challenge for Thermo King involved thedevelopment of what it calls its e-Kanban system (a signaling system to triggeran action such as inventory replenishment) that enables it to better manage thenumber of parts available at all assembly stations.

The manual part-replenishment system employed prior to adopting RFID hadseveral shortcomings. If workers discover they are running out of parts they must

contact management, either by phone or by walking to the person in charge ofordering replenishment. If the company's on-floor inventory of parts runs out,work is stopped until additional components can be brought in from thewarehouse. To avoid such problems in the past, companies typically store a highlevel of inventory at assembly stations. When space is tight companies need toestablish a kanban system in which they only pull inventory [from the warehouse]when it is required.

Thermo King first began discussing an automated solution with IMEC andAeroScout in early 2008 and the group conducted a proof-of-concept trial in Aprilof that year, in which it tested the hardware to ensure proper read rates, thendeployed the system throughout the entire factory in August. With the system,Ben-Assa says, the firm has installed approximately 100 AeroScout 2.4 GHz T2tags, with a tag mounted next to each container of parts.

When a container of parts runs low, an employee presses a button on its tag,which transmits its ID number to the Wi-Fi access points already installedthroughout the facility to allow wireless laptop connectivity. The tag transmits notonly its unique ID number, but also the assembly part serial number previouslyencoded when that tag was first installed. AeroScout Mobile View software linksthe ID number with the location at which the tag was installed, then transmits ane-mail alert to staff members in charge of replenishment, with the station numberand the part number required, as well as the time at which the order was sent.

10.9 Unit Review

BULLETLISTAutomatic identification and data capture (AIDC) is the use of technology toprovide direct data entry to a computer, or other micro-processor controlled


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system, without resorting to manual methods of data-entry, such as via akeyboard.

AIDC technologies consist of three principal technologies that are appliedsequentially; these are data encoding, machine reading, and data decoding.

AIDC can be categorised into optical, electromagnetic, magnetic, smart card,touch technique, and biometric technology types.

Errors with AIDC technology are measured by two parameters: First Read Rate,and the Substitution Error Rate.

Two types of barcode technology can be identified: linear barcode technology,and two-dimensional barcode technology.

Barcodes in Code 39 consist of an arrangement of nine bars and spaces, which

form a unique character for each arrangement; and a quiet-zone, consisting ofempty space, which both precedes and succeeds the barcode in its presentation.

The two basic types of 2-D barcodes are stacked barcodes, and matrixsymbologies.

Radio Frequency Identification technology represents the greatest threat toconventional barcode dominance as a data-capture mechanism.

RFID technology advantages include non-contact and non-direct identification,greater data-containment opportunities, and the ability to re-write to some tags, ifnecessary.

A RFID system consists of a number of RFID tags, RFID middleware, and theplants back-end computing systems. Communication can occur in bothdirections, both from the RFID tag backwards, and from the computing systemsforwards.

There are two types of RFID tag: active tags, which are battery-powered; andpassive tags, which rely on power drawn from the reader to be activated.

There are three different types of RFID memory: read only memory; randomaccess memory; and write once / read many memory.

RFID readers communicate with the RFID tags via radio waves and passinformation to the backend computer system in digital form.

RFID middleware acts as mediation between the RFID tag and the enterprisesystems back-end.


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Other AIDC technologies that may occasionally be used include: magnetic strips,optical character recognition, and machine vision technologies.ENDLIST

10.10 Self-Assessment Questions

NUMLISTList the principal types of AIDC technologies, and the categories that thesetechnologies can take.

What are the types of barcode technology that can be identified?

What is the major barcode standard that informs the use of barcodes made bymost of contemporary industry?

What are the two basic types of two-dimensional barcodes?

What are the advantages that are associated with Radio Frequency Identification(RFID) technology?

What are the major constituents of an RFID tag?

How does RFID middleware act in the RFID system?

Specify some other AIDC technologies.ENDLIST

10.11 Answers to Self-Assessment Questions

NUMLISTAIDC technologies consist of three principal technologies that are appliedsequentially; these are data encoding, machine reading, and data decoding.AIDC can be categorised into optical, electromagnetic, magnetic, smart card,touch technique, and biometric technology types.

Two types of barcode technology can be identified: linear barcode technology,and two-dimensional barcode technology.

Most major industries use a barcode standard that is based upon a subset ofCode 39, known as AIM USD-2.

The two basic types of two-dimensional barcodes are stacked barcodes, andmatrix symbologies.


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RFID technology advantages include non-contact and non-direct identification,greater data-containment opportunities, and the ability to re-write to some tags, ifnecessary.

An RFID tag consists of an infrastructure that contains a microchip, capacitors,

and antenna-coil. Depending on the tag type, it may or may not contain a battery.

RFID middleware acts as mediation between the RFID tag and the enterprisesystems back-end. It works as an effective data-filter, and subsequently developsbusiness events from the processed data that are sent to enterprise computingback-end systems.

Other AIDC technologies that may occasionally be used include: magnetic strips,optical character recognition, and machine vision technologies.END LIST

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