Data Acquisition System





Monday, January 28, 2008

Data Acquisition - Product Reviews

Generally data acquisition means to acquire data. However, in computer terminology, data acquisition is defined as the process of uniting real world data to produce the data to be maneuvered by the computer system. The data is in the form of waveforms or signals. These signals are obtained using different instruments and devices. The data acquired can be stored on the computer using vendor supplied software and the control can be made with the use of programming languages like Basic, Pascal, FORTRAN, C etc.

Data acquisition systems, as the name suggests are products or systems used to gather data or information from certain source. The data acquisition systems are distinguished on following basis: serial communication, USB, parallel ports and plug-in boards.

Without going much in depth, below are the details of different data acquisition boards.

Signatec PDA1000: This is the data acquisition product made by Signatec. The PDA100 is a 64-bit data acquisition board compatible with PCI device equipments. The "Plug and Play" feature is standard in all PCI devices. The analog bandwidth of DC to 500 MHz and digitization rate of up to 1 MHz makes it remarkably unique in its class. The bus that it uses is a Signatec Auxiliary Bus (SAB). This bus can allow data of 500 MB to be transferred per second. Multiple PDA1000 boards can be connected to the same PDA1000 DAQ board in the master-slave configuration through an interconnect port. It has six selectable signals ranging from 200 million volts to a maximum of 3.2 volts.

OME-PCI-1002 series: This data acquisition board is made by Omega. It features 12 bits 110 KHz analog to digital converter PCI board. The PCI board provides 32 single ended or 16 differential inputs along with 16 digital input and 16 digital output channels. This PCI board series provide sampling rate of 110 KS/s. However, it may vary within the series depending on whether the channels are single or multiple. Unlike many other company boards, the omega OME-PCI-1002 comes with software development kit compatible with Windows 98/NT/2000/XP. This software development kit includes DLL files for high level programming languages and OCX files for Active X programming.

iOTech DaqBoard-3000 series: This is a multifunction data acquisition board embedded with four 1 MHz PCI boards. Unlike OME-PCI-1002 board, this board has 16 single-ended or 8 differential analog inputs with the option to expand them up to 64 single-ended or 32 differential analog inputs. DaqBoard-3000 series has 24 high-speed digital I/O lines. There are four 32 bit counter input channels with quadrature encoder capability. It supports multiple DMA channels and USB version of this board is also available in market.

Advantech PCI-1670: This is a high performance PCI board with GBIB interface. PCI-1670 board works fully with IEEE 488.1 and 488.2 standards. It has full functionality with windows 95/98/NT/2000/XP and MS-DOS operating systems. The "Plug and Play" feature automatically assigns I/O address and provides powerful and easy to use configuration utility. It also has full support for drivers and libraries of C/C++, C++ Builder, Visual Basic and Labview.

Michael Russell

Your Independent guide to Data Acquisition

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Friday, January 25, 2008

Data Acquisition: Closed-Ended Questionnaire Response Format

Interviewer and coder bias are removed because the interviewer is simply checking a box, circling a category, recording a number, or punching a key. Reading response alternatives may jog a person's memory and provide a more realistic response. Also, because the option of expounding on a topic is not given to a respondent, there is no bias toward the articulate. Finally, the coding and data acquisition process is greatly simplified.

There is a difference between a pre-coded open-ended question and a close-ended question. An open-ended question allows the respondent to answer in a freewheeling format. The interviewer simply checks the points on the pre-recorded answers as they are given. Probing is used, but a list is never read. If an answer is given that is not pre-recorded, it is written verbatim in the 'other' column. In contrast, the closed-ended question requires alternatives to be read or shown to the respondent.

Traditionally, the data acquisition process has separated the two-item response option from the many-item type. A two-choice question is called dichotomous and the many-item type is often called multiple-choice or multi-chotomous. With the dichotomous closed-ended question, the response categories are sometimes implicit. For instance, how would you respond to the following question: "Did you buy gasoline for your automobile in the last week?" Obviously, the implicit options are "Yes" or "No", regardless of the fact that a respondent may say, "I rented a car last week and they filled it up for me. Does that count?" the questions would still be classified as dichotomous closed-ended.

The simplest form of data acquisition is a closed-ended question or dichotomous choice. They are easy to administer and usually evoke a rapid response. For example, limiting the responses to a simple "Yes" or "No", "Agree" or "Disagree" or "Greater than" or "Less than". Many times a neutral or " no opinion/don't know" option is added to dichotomous questions to take care of those situations. Sometimes the interviewer will jot down "DK" for "Don't know" or "NR" for "No response" if the neutral option is omitted from the data acquisition questionnaire.

Dichotomous questions are prone to a large amount of measurement error. Because alternatives are polarized, the wide range of possible choices between the poles is omitted. Thus, question wording is very critical to obtain accurate responses. Questions phrased in a positive form may well result in answers opposite from those expressed in a negative format. In questions requiring a "Greater than" or "Less than" response, response may vary. These problems can be overcome using a split ballot technique. One-half of the questionnaires are worded with greater than listed first and the other half with less than first. This procedure will aid in reducing potential bias.

Each type of closed-ended question has unique disadvantages. For the dichotomous data acquisition form, frequently the responses fail to communicate any intensity of feeling from the respondent. In some cases, the matter of intensity does not apply, as for the previous example on gasoline purchasing, but instances do arise in which the respondent feels very strongly about an issue but the intensity is lost in the dichotomous data acquisition form. The multiple response closed-ended question has two additional disadvantages. First, the researcher must spend time gathering the list of possible responses, secondly the range of possible answers. If the list is too long, respondents may become confused or disinterested.

Michael Russell Your Independent guide to Data Acquisition

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Monday, January 21, 2008

Data Acquisition: Deciding On Questionnaire Wording

It is a skill developed over time and subject to constant improvement. Four general guidelines are useful to bear in mind during the wording and sequence of each question posed in the data acquisition process.

(1) The wording must be clear: If the researcher decides that a question is absolutely necessary, that question must be stated so that it means the same thing to all respondents. Ambiguous terminology should be avoided, such as "Do you live within five minutes of here?" or "Where do you usually shop for clothes?" The first example depends on the mode of transportation (maybe the respondent walks), driving speed, perceived elapsed time and other factors. It would normally be prudent to show the respondents a map with certain areas delineated and ask if they live within the area. The second question depends on the type of clothing, the occasion, the member of the family and the meaning of the word where.

Clarity also implies the use of reasonable terminology. A questionnaire is not a vocabulary test. Jargon should be avoided and verbiage should be geared to the target audience. Every prospective respondent represents a separate frame of reference. That is, each person is unique in personality, mental ability, experiences, education and views of the world. Therefore, the questionnaire designer must use terminology native to the target respondent group and not to research jargon. The first task of wording questions, then, is to translate questions into everyday language.

(2) Select words as to avoid biasing the respondent: A question such as, "Do you often shop at lower class stores like K-Mart?" evokes an obvious response. Similarly, "Have you purchased any high-quality Black and Decker tools in the past six months?" also biases respondents. Questions can be leading, such as, "Weren't you pleased with the good service you received last night at the Holiday Inn?" These examples are quite obvious. Unfortunately, bias may be much more subtle than is illustrated in these examples.

Sponsor identification too early in the interviewing process can also distort the data acquisition process. It does not take long, for example, for a person to recognize that a survey is being conducted for Miller beer if, after the third question, every question is related to this product. Similarly, an opening statement such as, "We are conducting a study on the quality of banking for Northeast National Bank and would like to ask you a few questions" can influence responses. Sometimes, of course, the true purpose of the study must be disguised to obtain an unbiased response.

(3) Consider the ability of the respondent to answer the question: in some cases, a respondent may have never acquired the information to answer the question. Asking a man, which brand of sewing thread is most preferred by his wife would often fall into this category. Asking a respondent about a store or brand that they have never encountered creates the same problem. When a question is worded in this manner, it often pushes the respondent to give a wild guess. This creates measurement error, since uninformed opinions are recorded and the data acquisition process renders false statistics.

(4) Consider the willingness of the respondent to answer the question: The memory of the respondent may be totally clear, yet the respondent may not be willing to give a truthful reply. Reporting of an event is likely to be distorted in a socially desirable direction. If the event is perceived as embarrassing, sensitive in nature, threatening, or divergent from one's self-image, it is likely either not to be reported at all or to be distorted in a desirable direction. One technique is to ask the question in the third person. For example, "Do you think that most people charge more on their credit cards than they should? Why?" By asking about "most people" rather than about the respondents themselves, researchers may be able to learn more about the respondents' attitude about credit and debt. This data acquisition method makes embarrassing topics less intimidating for the respondent to discuss.

Michael Russell Your Independent guide to Data Acquisition

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Wednesday, January 16, 2008

Data Acquisition: Open-Ended Questionnaire Response Format

Often open-ended questions require 'probes' from the interviewer. A probe is encouragement from the interviewer for the respondent to elaborate or continue the discussion. The interviewer may say, "Is there anything else?" or "Would you elaborate on that?" Probes aid in clarifying the respondent's interests, attitudes and feelings. Today computers are playing an increasingly important role in data acquisition - analysing and recording probes to open-ended questions.

Open-ended questions offer several advantages to the researcher. They enable respondents to give their general reactions to questions like: (1) What advantages, if any, do you think ordering from a mail-order catalogue company offers compared to local retail outlets? (probe: what else?). (2) Why do you have one or more of your rugs or carpets professionally cleaned rather than cleaning them yourself or having someone else in the household clean them? (3) What is there about the colour of product that makes you like it the best? (probe with: what colour is that?) (4) Why do you say that brand is better?

Note that in questions 2 and 4, the open-ended question is part of a skip pattern. In question 2, for example, the respondents have already indicated that they use a professional carpet cleaning service and do not depend on members of the household.

Another advantage of open-ended responses is that they can provide the researcher with a rich array of data. Respondents are answering from their own frame of reference. Advantages are described in 'real world' terminology rather than laboratory or marketing jargon. Often it is helpful in designing promotion themes and campaigns. It enables copywriters to use the consumers' language. This rich array of data can now be captured even in computer-assisted interviews, streamlining the data acquisition process.

The inspection of open-ended data acquisition can also serve as a means of interpreting closed-ended questions. This analysis often sheds additional light on the motivations or attitudes behind the closed-ended response patterns. It is one thing to know that colour ranks second in importance out of five product attributes. But it might be much more valuable to know why colour is important. For example, a study on mobile home park residents might uncover a great deal of dissatisfaction with the trash pick-up service. However, further inspection of answers to an open-ended questionnaire may uncover that the reason for the dissatisfaction may have been caused by freely roaming dogs overturning the trash receptacles and not shoddy work on the part of the trash pick-up service.

Similarly, open-ended questions may suggest alternatives not listed in a closed-ended data acquisition questionnaire. For example, a previously unrecognised problem relating to the trash pick-up service might be uncovered from an open-ended data acquisition questionnaire. Open-ended questions are not without their problems. One factor is the time and money consuming process of editing and coding.

Editing open-ended responses requires collapsing the many response alternatives into some reasonable number. If too many categories are utilized, data patterns and response frequencies may be difficult for the researcher to interpret. If the categories are too broad, the data is too general and important meanings may be lost. The open-ended question data acquisition process may also be influenced by interviewer bias. Although training sessions continually stress the importance of verbatim recording of open-ended question, it is often not practised in the field. Open-ended questions may also be biased toward the articulate interviewee. A person with elaborate opinions and the ability to express them may have much greater input than a shy, inarticulate, or withdrawn respondent. Yet both could be equally likely prospects for a product.

Michael Russell Your Independent guide to Data Acquisition

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Thursday, January 10, 2008

Managing Data Analysis in TQM Improvement Project - Tips to Cut Down 80% of Time Spent in Data Entry

This article is written for team member who are either not formally trained in using the MS Excel spreadsheet or not even read a training manual in using MS Excel. But they are required to deal with data collection and compilation in their routine job or in this TQM Improvement project.

I am sharing this because as a facilitator to TQM Improvement Team, I have seen team members spend unnecessary time dealing with data collected and managing these data. To appreciate the content of this article, reader must understand the basics of MS Excel in terms of terminology, example; menu, scroll bar, cell, row and column etc. I am going to share with your some of the common mistake that my team members did without knowing they can cut down up to 80% of their time. Firstly, I like to cover the following topics.

Layout of the worksheet

Very often, the first row of the worksheet is used up for a title of the spreadsheet. Let’s say we call it "Material Loss Report". In some case, team member use up more than 3 rows. Then several rows are left blank, the title is keyed in say in row 5. Then the first title is keyed into cell B5. Let me illustrate what I meant as follows:-

At Cell:B5,

Date Line # Process Name Loss qty

12/6/06 2 Polishing 231

Data Entry Method

Having properly designed layout in the spreadsheet would save a lot of time in data entry using some of the build in functions in MS Excel. An effective data entry would result in data accuracy and integrity which is very critical for an improvement project.

Here is what I meant; Often, team members would move their cursor into the spreadsheet to do data entry within the format they created. It is not an issue when the spreadsheet is still small can contain not too many row or column. However, it will become very tedious when the number of row and column increases. Next issue is that data entry into the spreadsheet direct from the format will create data entry error due to fatigue.

What is the option then, it is simple. Use the build in function in the "data" menu, click on the "form". A form will appear that show the title above in the nice format for easy for data entry. When data is completed for one record, you click the close button, the data will automatically updated to the spreadsheet.

While you are still in the form, options are available to add new record, Find Prevrecord; find Next record; or close the data entry form etc. It is a smart and simple build in function to use for data entry.

Please click To View Graphic explanation of Data Entry Form

My next article will share with you tips on how to do a fast quality control with your data spreadsheet.

The author provides consulting services specializing in TQM Implementations in manufacturing and service sector. He provides facilitation workshops and hands-on application in Cost Reduction and Productivity Improvement projects. He publishes TQM articles, ebooks, case studies, trainer manual and presentation slides. Please click To View Free TQM articles or Please Visit my Web Site for other TQM related matters

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Monday, January 7, 2008

Innovation Management - Rigorous data analysis

Creativity can be defined as problem identification and idea generation whilst innovation can be defined as idea selection, development and commercialisation.

There are other useful definitions in this field, for example, creativity can be defined as consisting of a number of ideas, a number of diverse ideas and a number of novel ideas.

There are distinct processes that enhance problem identification and idea generation and, similarly, distinct processes that enhance idea selection, development and commercialisation. Whilst there is no sure fire route to commercial success, these processes improve the probability that good ideas will be generated and selected and that investment in developing and commercialising those ideas will not be wasted.

Rigorous data analysis

Problem identification is often considered the most boring aspect of creativity. But it is in fact the most crucial. If you’re not working on the right problem, then you’re working towards the wrong solution; all energy, time and resources are being wasted. Ideally, problem identification should occupy more time than idea generation.

Ask a group of ten people what the problem is and you are likely to get eleven answers.

Each suggestion the above group of individuals give will be valid in it’s own way, but how do we really distinguish between the best and the least best answers?

The answer is to apply a rigorous standard of information analysis.

It is from rigorous data analysis that you are able to discover which of your clients provide most revenue, how each demographic responded to a marketing campaign, why your top clients didn’t buy the green latest Aston Martin or why 70% of respondents thought your advertising campaign too patronising.

The above analysis yields a whole new set of problem identification answers and a higher probability that your solutions will not be misdirected.

These and other topics are covered in depth in the MBA dissertation on Managing Creativity & Innovation, which can be purchased (along with a Creativity and Innovation DIY Audit, Good Idea Generator Software and Power Point Presentation) from http://www.managing-creativity.com/

You can also receive a regular, free newsletter by entering your email address at this site.

Kal Bishop, MBA

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You are free to reproduce this article as long as no changes are made and the author's name and site URL are retained.

Kal Bishop is a management consultant based in London, UK. He has consulted in the visual media and software industries and for clients such as Toshiba and Transport for London. He has led Improv, creativity and innovation workshops, exhibited artwork in San Francisco, Los Angeles and London and written a number of screenplays. He is a passionate traveller. He can be reached on http://www.managing-creativity.com/

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Friday, January 4, 2008

Benefits of the Universal Serial Bus (USB) for Data Acquisition

Imagine adding data acquisition capabilities to your PC as easily as plugging in a mouse or a keyboard. Just connect a compact data acquisition module to your computer (you don't even have to power-down), install the supplied software, and connect your sensor directly to the module. In minutes, and with state-of-the-art accuracy, you're capturing data: temperature, pressure, sound level, whatever you need. And you have done this without programming, without opening up your PC, without even thinking of IRQs, board configuration, power requirements, or connection schemes.

A pipedream? Not any more. This convenience and power are available today, thanks to the USB, a serial expansion bus, and to a growing range of USB-compatible data acquisition function modules. Together, USB bus and modules greatly simplify the way people perform data acquisition on PCs.

USB: A Truly Universal Bus for Computer Peripherals

Today, virtually all desktop and laptop PCs on the market provide USB ports. USB ports for existing PCI Bus machines can easily be added. Equally important, these USB ports have full software support under the most popular personal computer operating systems, including Microsoft Windows 2000 and XP.

The USB standard was created by a group of manufacturers (including Intel , Microsoft, and Compaq) to simplify the connection of external peripherals to personal computers. The USB foundation's web site (http://www.usb.org) has detailed information on the features of USB.

Are one or two USB ports enough? Expandability is another USB strong point. Up to 127 devices can connect to a single port simultaneously, using expansion hubs and cable assemblies that are widely available at low cost.

USB 2.0 Improvements

The first specification for USB, version 1.1, featured 12 Mb/s (megabits per second) data throughput, which is fine for moderate-speed applications, including most data acquisition uses, but not fast enough to support video, imaging, and highest-speed data acquisition applications. This technical limitation was addressed with a new version of the USB specification. In April 2000, the USB 2.0 Promoter Group released the final USB 2.0 specification. USB 2.0 exceeds the previous version's speed barrier with 40 times the bandwidth: 480 Mb/s. Advances such as larger packet size and new transfer modes make high-speed transfers more efficient. As higher-performance USB peripherals become more widespread, 2.0's additional bandwidth will make it feasible to connect more USB peripherals, supporting multi-tasking software operations without slow-downs. USB 2.0 (Hi-Speed USB) is fully compatible with USB 1.1 (Original USB), and uses the same cables and connectors.

Easy Installation Since ease of use was primary in the creation of the USB, many features have been designed in to make USB devices among the easiest to install. To begin, USB devices are true "plug-and-play". There is no setting of address lines, interrupts, or configuration jumpers. The host PC automatically identifies a peripheral when it is plugged in, and searches for the software necessary to operate it. The first time a device is used, the user is prompted to install the drivers and application, a process that takes just a few minutes. Ease of installation means USB peripherals can be shared between computers, even between laptop and desktop models.

USB devices are also external to the computer -- there is no need to open up the computer to install them. This external location also provides performance benefits for noise-sensitive devices like data acquisition peripherals: They are away from the computer's noisy motherboard and power supplies, and closer to the sensors they will be measuring.

Hot-swappable USB devices are designed to be installed or removed while the computer is running. Peripherals no longer need to clutter the workspace when they aren't needed. Just plug the device in, use it, then remove it when done.

Peripherals can either be powered by the USB or from an external power source. Being powered from the USB is most convenient, but, since only limited power is available, a device must typically be designed from the ground up for USB operation.

USB devices can plug directly into a USB port, located on the PC, in powered hubs that can be standalone, or built into monitors and computer peripherals.

Connection to the PC is easy, too. A single, low-cost cable (from 1 to 5 meters long, and often supplied with the peripheral) carries power and signal connections to the USB device. Since all devices use the standard cables, USB users don't have to hunt down expensive, hard-to-find adapters to change the pin configuration or "gender" of connectors before they can use their peripheral. USB cables are available off-the-shelf at computer and office-supply stores.

USB devices for data acquisition may also include removable terminal blocks that conveniently handle all user I/O connections. This saves time and money: No external screw terminal panel is required.

Worry-Free Operation Perhaps the most profound benefit to the USB is the confidence it inspires in PC users of all levels of experience. Anybody who can operate a PC can install a USB peripheral and have it running in minutes.

For data acquisition users, this benefit can be enormous. No longer does the peripheral gather dust until a computer expert can install it, or a busy scientist can take hours or days to figure out how to configure and program it for the task at hand. Because USB devices work directly with most laptops, even the most sophisticated data acquisition applications come out of the lab and into the field.

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