Monitor Newsletter Archive
Home
Newsletters
Shop
|
Issue 10: Specifying a Data Acquisition System; Bookshops
CONTENTS
Windmill news | Choosing a data acquisition system
| Analysis of data | Automation | Affordability | Pitfalls | Bookshops
Our Streamer software, together with the Microlink 570 plug-in card, is now available from our on-line shop at http://www.windmillsoft.com/acatalog/570.html
Streamer is a suite of software for waveform capture. With Streamer you can log data to disk at high speed (up to 100000 samples per second), chart data in real time, save libraries of set-up files and examine graphs of data after collection. You can download a free demo of Streamer from http://www.windmill.co.uk/strdemo.html.
For lower speed applications (up to 200 samples per second) subscribers can try a free copy of our Windmill software.
When choosing a data acquisition and control system, you'll consider the obvious features such as number and type of inputs and outputs, communications used, sampling speeds, and so on. However, less attention is often paid to features that make the system easier to use, more functional and that bring the overall cost down.
- Can the data be analysed and compared in real-time with the raw data? This is particularly useful in applications where raw data needs to be processed and then compared with some standard values in pass/fail applications.
- Can the saved data be automatically archived in a logical, easily accessible, way? This aids the procurement of historic data when accountability is needed, for example if failures occur after production.
- Is the data suitable for input into a Statistical Process Control procedure? Used in PID (proportional, integral, derivative) applications to control a process depending on the relationships with raw data values.
*
- Can the tests or experiments be automated - improving repeatability?
- Can the system not only log data unattended, but also detect and shut down if any problems are detected?
- Can reports be generated directly from the software? This often leads to more accurate data as it eliminates the risk of transcription or typographical errors.
*
Due to the ever-decreasing cost of PCs and peripherals, a dedicated computer to run the data acquisition system is not a major part of your budget. Many software applications can swap data within the PC through DDE (Dynamic Data Exchange); hence systems can be built with off-the-shelf products. Because of the time savings gained by the automation and the data analysis features, the computerised measurement and control systems can pay back the investments in a short space of time.
*
When considering all the requirements for your data acquisition system, which can often take much deliberating and last for many months, it is important not to get bogged down with unnecessary details. There are a few common pitfalls that you should be aware of.
- Having a large committee of people involved in the decision making process can blur the ultimate goal of the system. As a first step compose a list of requirements and priorities, and refer to this throughout the process.
- Not seeing the hardware and software as intrinsically linked, and assigning a separate hardware and software specialist that have little or no contact with one another. A demand in one area is generally linked to the other. It may also produce difficulties if any problems arise, as the technical support will need to know how the hardware and software behave together.
- Trying to choose hardware and software without a clear understanding in your own mind of exactly what is required is also a problem. Telling the manufacturer exactly what you have at the moment, what you will need from the system, and any long-term future requirements will make the whole process much easier. Trying to work it out as you go along and moving the goal posts half way through, will almost certainly lead to failure.
- Choosing a manufacturer that doesn't offer comprehensive technical support is another obvious pitfall. If you need to change your set-up, or if someone else takes over the project, adequate technical support can be invaluable. The same is true of course if any failures occur with the system.
- Finally don't eliminate equipment that doesn't contain every single feature that everyone working on the project needs at the moment, or would like to have in the future. Manufacturers can never design a system that will please everybody, all the time. So unless you want a complete custom solution, which is potentially very costly, trying to find some middle ground is usually the best way to avoid shutting out solutions that are otherwise well suited to the application.
I hope these points have given you a better idea of how to progress if you are currently considering a computerised data acquisition system, or indeed if you wish to upgrade a system you already have. The aim is to obtain a system that doesn't just put data on a screen for you, but gives a complete solution to make your process more accurate, reliable and efficient.
By Ben Worthy
It's often quicker, easier and cheaper to buy books on the internet than by conventional means. There are sites that let you compare prices across a series of internet bookshops, sites that locate books that you can't find, second-hand and new bookshops, and bookshops specialising in science and engineering.
- Amazon
-
The most famous internet book shop is perhaps Amazon, which offers many reductions and has sites in the US (amazon.com), UK (amazon.co.uk) and Germany (amazon.de). Many independent sites sell books through Amazon, and these might be a better place to start than Amazon itself. They select and categorise books according to their specialisms. One of the many examples of such an Amazon affiliate is the Microlink Bookshop,
http://www.microlink.co.uk/books.html
-
Acses
-
Although not selling books itself, this site lets you select a book and compare prices across a wide range of bookshops. A very useful site that lets you choose your location and currency, includes postage charges in the final comparison, and tells you delivery times.
http://www.acses.com/
-
Book News
-
This site lists recently published books in science, technology and medicine from specialist publishers around the world. All the books are immediately available. Choose a subject, browse through to a book, and open the publisher's site. However, you will then have to search the publisher's site again to order the book. Still, a useful site for locating hot-off-the-press books.
http://www.booknews.co.uk/
-
Powell's Books
-
Claims to be the largest new and used bookstore in the world (used books appear to far outnumber new books). Includes a "Control Engineering Instrumentation and Measurement" section, and offers on-line ordering.
http://www.technical.powells.com/
- Eagle Electronic Bookshop
-
Specialise in trading new and second hand academic texts - either directly or through related partnerships. Special areas of interest include science (especially physics and high energy particle physics), business and other educational texts. No on-line ordering: you're asked to e-mail if want to make a purchase. Not a large selection but worth looking at if you can't find what you're looking for elsewhere.
http://www.eagle.co.uk/bookshop/
- CRC Press
-
Publishers of scientific, business, professional and technical books. You can search by discipline - restricting results to life sciences, engineering or physical sciences say - or browse, drilling down to increasingly specific categories. Easy on-line ordering and opportunity for you to be informed of upcoming publications in your chosen subject. Extremely easy-to-use site.
http://www.crcpress.com/
-
Institute of Physics Bookstore
-
Specialise in books about science and physics. The list is particularly strong in core physics subjects, but also associated and interdisciplinary areas such as engineering and computing science. Institute of Physics Publishing is a not-for-profit publisher, "promoting the advancement and dissemination of knowledge about physics". This lets them publish works other commercial companies may not be able to. Can order on-line.
http://bookmark.iop.org/
- Blackwells
-
UK academic bookshop which ships world wide and is currently offering free postage within the UK. If you cannot find a book in their catalogue of 1.5 million titles, their specialist Book Search agent will attempt to find a copy for you and contact you directly regarding price, delivery and payment.
http://bookshop.blackwell.co.uk/
- Macmillan Press
-
The Science and Technical site includes a wide range of books and multimedia from Macmillan and its sister companies. It includes undergraduate and graduate textbooks, professional books, and popular science books. Can browse and search the catalogue, which includes a small Control, Instrumentation and Measurement section.
http://www.macmillan-press.co.uk/science/
- John Wiley & Sons, Inc.
-
Publishes and sells books for the educational, professional, scientific, technical and medical markets. Lets you select your country so their catalogue will only show books available in your area. You can search for a book among more than 11,000 listed, or browse through their subject-specific catalogues. They have sites in the UK, US, Australia and Germany and ship worldwide.
http://catalog.wiley.com/
- ISA Bookstore
-
Reference books on process control, industrial automation, and test and measurement instrumentation, with on-line ordering.
http://www.isa.org/reference/index.cfm
- IEEE Books and Conference Proceedings
-
Search more than 1,500 IEEE books & conference proceedings. You can also browse 92 subject categories, each showing the quantity of books in that section. No on-line ordering, but you can print out and post an order form.
http://engine.ieee.org/titles/bwshop.htm
- Channel Tunnel Publications
-
Curiously, this site is dedicated to publications about the British-French channel tunnel. It offers over 300 publications on the unique under Channel link. Books are listed in categories such as construction, education, environment, engineering, technical reports and trains. No on-line ordering but can e-mail, telephone, fax, or post orders.
http://www.channeltunnel.co.uk/
- Opamp Technical Books
-
California based Opamp Technical has a large selection of professional and educational technical books. Not a very attractive site, but can browse through and search categories, and order on-line with 5% or more discount.
http://opampbooks.com/
- Academic Press
-
A publisher and bookseller for scientists, researchers and engineers in industry and academia. Offers more than 6000 titles and worldwide on-line ordering.
http://www.apcatalog.com/
- Balogh Scientific Books
-
An agent for Cambridge International Science Publishing, specialising in materials science, engineering, metallurgy and corrosion science. Also includes English translations of Eastern and Central European journals. No on-line ordering, but invites you to e-mail orders.
http://www.balogh.com/british/cisp.html
Do you have a comment or suggestion for this newsletter? Why not
email the editor - Jill - at studholme@zetnet.co.uk
Copyright 1999 Windmill Software Ltd. All rights reserved.
This newsletter may be distributed in its entirety. However, individual sections may not be reproduced without the prior written agreement of Windmill Software Ltd.
Subscribing
To subscribe to Monitor please fill in your email address below. We will not pass your address to any third parties.
|
Free measurement news feed...