Windmill Software Ltd
Windows Engineering Software

July 2004

The Newsletter for PC-Based Data Acquisition and Control
Issue 72           July 2004
--------------------ISSN 1472-0221----------------------

Welcome to Issue 72 of Monitor.  This month we're 
delighted to announce our live data acquisition news 
feed.  In RSS format, it lets you pick up the latest on
new products, articles and events in the measurement 
and control field.  

We hope you enjoy receiving Monitor, but should you 
wish to cancel your subscription you can do so at

* Windmill News: Grab Live Data Acquisition News
* Windmill Notes: Interfacing Modbus Devices
* GIS Resources
* Excel Corner: Automatically Generating Reports III

Windmill News: Grab Live Data Acquisition News

Monitor now offers a live news feed at 
This means that you can receive data acquisition and 
control news as it is published, without waiting for our 
newsletter or other publications to arrive. 

The news feed is in RSS format. This is a standard format 
that can be picked up by many different sites and 
applications.  For example, you can read the news 
feed through...
1. One of your own web pages.
2. A web-based news reader or "aggregator".
3. A software application running on your desktop.
4. E-mail.
5. A "ticker" on your desktop
6. On one of our web pages.

You are not limited to receiving our news, but can add 
any other RSS news feed and see news from different 
disciplines in the same place.  You are in complete 
control of the news feeds you subscribe to, and 
completely anonymous. The provider of the feed (such as 
ourselves) will never know anything about you. 

1. Embedding the Updating News in your own Web Page
You can embed the data acquisition and control news in 
your own web page. The latest news will then 
automatically appear in your page. To do this just cut 
and paste the following javascript code into your 
page. For an example of this in action see our site at

You can customise the look of the news feed: just edit the javascript code. - To show more headlines edit: feed_maxitems=5 - For a wider box edit: feed_width=200 - For a different background colour edit: box_bgcolor=ffffcc - To open links in a new window change the 0 to 1 in: link_openblank=0 2. Using a Web-Based News Reader ================================ Several companies provide a service where you can see several newsfeeds in your web browser. For example, if you have a myYahoo account, you can add news feeds to your page there. To open a myYahoo account go to If you already have a myYahoo account, select this link to add the Monitor feed. Another news reader which is quick to set up is "Rocket" ( Create a Rocket account then add The advantage of a web-based news reader is that you can access it from any computer. 3. Using a Software News Reader ================================= With this option you download some software which displays the news for you. This means that you are able to read the news off-line. They also often provide more features than are available with web-based readers. However, you are limited to reading the news on your own PC. Two examples of these are FeedDemon ( and Headline Viewer ( You will need to add our news feed ( 4. Receiving News Via E-mail ============================== There are various services which will deliver the latest news to your e-mail account, such as MyRssAlerts ( and ERA ( You need to tell them that you want to receive news feeds from 5. News Tickers ================= Another option is to display the news in a "ticker" on the Windows desktop. This has the advantage of only taking a small area of your computer screen. RDF Ticker ( is one company which offers this option. 5. Viewing News at our Site ============================= To view the live news at our site, point your browser at For more details on our news feed see or contact [email protected] ________________________________________________________ ________________________________________________________ Windmill Notes: Interfacing Modbus Devices ________________________________________________________ Modbus devices connect to the PC over a serial line using the Modbus protocol. Our free ComDebug software lets you troubleshoot your Modbus connection. You can also use it to check whether the Windmill Modbus driver will work with your device. To download the free ComDebug software go to Unzip the software using WinZip or similar, and run setup.exe to install. If you haven't purchased the COMIML Modbus driver, then choose to use ComDebug as a Terminal Utility. Enter the necessary settings into the Prompt Grid, as detailed below. ComDebug supports any mix of digital and analogue inputs and outputs. These can be distributed across any set of Modbus slave devices. You can configure the slave device address and the parameter number (register number) for each channel individually. The Modbus protocol defines two modes of transmission: ASCII and RTU (Remote Terminal Unit). ComDebug supports both modes. In ASCII mode each 8-bit byte in a message is sent as two ASCII characters. It allows intervals of up to 1 second between characters, without causing an error. Messages start with a colon and end with a Carriage Return followed by a Linefeed. In RTU mode each 8-bit byte in a message contains two 4-bit hexadecimal characters. Greater character density allows better data throughput than ASCII for the same baud rate. Each message is transmitted in a continuous stream. The final part of a RTU message is a cyclic redundancy check, CRC. This calculates its value based on all earlier bytes in the message, it then adds its 2 bytes into the message. The computer therefore knows when it has received a corrupted message and can ask the instrument to resend its data. Modbus Settings =============== Use the prompt grid in the ComDebug Terminal screen to send commands and data to your Modbus device as a series of bytes. Use the NonPrint menu to enter addresses, codes, etc. For example, to enter a device address as Byte 1, select NonPrint Decimal from the NonPrint menu. Type the device address into the blue box. Address 1, for example, would be shown as Char 001 (and Hex 01). To Read a Single Modbus Register ================================ Byte 1 = device address Byte 2 = Modbus function code: 3 or 4 Byte 3 = msb of register Byte 4 = lsb of register Byte 5 = msb of number of bytes to read: normally 0 Byte 6 = lsb of number of bytes to read: for example 2 Byte 7 = CRC: use the CRC menu The Reply Comprises Byte 1 = device address Byte 2 = function code Byte 3 = number of bytes read Byte 4 = 1st word, msb Byte 5 = 1st word, lsb Byte 6 = 2nd word, msb Byte 7 = 2nd word, lsb etc Byte n = CRC To Write to a Register ======================== Byte 1 = device address Byte 2 = Modbus function code: 6 Byte 3 = address of word, msb Byte 4 = address of word, lsb Byte 5 = value of word, msb Byte 6 = value of word, lsb Byte 7 = CRC The Reply Comprises Byte 1 = device address Byte 2 = function code: 6 Byte 3 = address of word, msb Byte 4 = address of word, lsb Byte 5 = value of word, msb Byte 6 = value of word, lsb Byte 7 = CRC If you choose to purchase the COMIML Modbus driver package, then this includes the Windmill programs to log data, chart data and control your Modbus device. You can also pass data, in real-time, to other Windows software like Excel or Access. More Information: ================= ________________________________________________________ ________________________________________________________ GIS Resources ________________________________________________________ A GIS (geographical information system) is a special case of data acquisition. In GIS applications, a computer stores and displays attribute data (temperature, depth, etc) identified according to its location. There are many resources on the internet for GIS, here are some of the better ones. Launched several months ago, has rapidly become a must-see resource for GIS end users and professionals. The site has been conceived and developed by the publishers of The American Surveyor Magazine and long-time GIS industry media veteran Glenn Letham. Visitors will find a fresh site with loads of daily updates, most noteworthy being news announcements, a daily spotlight feature, special feature articles, free tools and scripts and a comprehensive GIS data catalog of pointers to free data resources. It boasts a popular weekly newsletter that summarises the site's most recent additions and is currently offering people who subscribe a chance to win prizes (software from SAFE, a speedy graphics card, GITA industry market research report). Details on their latest contest are at GIS Lounge Provides introductory text for issues relating to GIS as well as pointers to further information. "GIS is a powerful tool to help record, analyze and map spatial data. GIS Lounge helps you learn more about GIS and how to use its amazing applications to benefit your work. GIS isn't just for geographers, it's for anyone." GISCafe News, resources, discussion, technical articles and white papers. A news-based site which selects the most important news stories available. Concentrate on GIS products and datasets, announcements, photogrammetry and aerial photography surveying. GIS Development Applications, news, downloads, technology, tutorials, products, dissertations, companies. . .they claim to have it all. Geoplace Weekly features, product reviews, events calendar and directory of products and services. Resources at the Windmill Web Site GIS Overview Connecting a GPS Receiver to a PC Remote Sensing: Low Cost, Fast and Accurate Seafloor Mapping Mapping Dye Dispersion Seabed Surveying and Mapping Investigating Submarine Spring Pollution ________________________________________________________ ________________________________________________________ Excel Corner: Automatically Generating Reports III ________________________________________________________ Welcome to third in our series of articles on how to automatically generate reports in Excel. If you missed The previous two issues you can find them at Previously we've shown how to run daily, monthly or weekly reports calculating the mean, maximum and minimum values for each channel. New this month is the "Calculated Channels" option. This lets you combine readings from physical channels of data and create new, virtual, channels. For example, say you were logging data from electricity meters every quarter of an hour. You might want to compare usage at one site with another. You could add the readings from all the meters at site one to produce a total, and do the same at site two. These totals would each be saved in a new, calculated channel. The beauty of saving the calculations in channels, is that Excel can then display the data in columns alongside the real-world electricity readings. So instead of a total for the day, you could see regular updating totals. In our example every quarter of an hour. Downloading the Report Generator ================================== The new report generator is available at Unzip this into your Windmill folder. You need to load the reportWL3.xls worksheet from Excel (rather than double-clicking on the xls file). Using the Report Generator ========================== When you open the xls file, Excel looks for valid Windmill Logger data files. It considers a file to be valid when you have periodic logging enabled in Windmill Logger, with no files being overwritten. It will also look for any calculated channel definitions - see below for details of these. Excel then lets you choose which set of data files to analyse. Make your selection from the File Prefixes box in the opening form. You can then choose how to analyse the data: select the summary type from Maximum value, Minimum value, Sum or Mean. Choose a date for the report and whether the report should cover a day's, a week's or a month's data. Now press the "Make Report" button and Excel will generate the report according to your specifications. Creating Calculated Channels ============================ Calculated channel definitions are stored in an Excel spreadsheet called calcChansWL.xls. We've included an example in the download. For each calculation you need to enter the name of the new calculated channel into the first column, and the formula for this calculation into the second column. When creating a formula, to reference other channels (calculated or physical) enclose their names in square brackets. For example [MyChan] or [Meter1]. The Operators supported are: / * - + in that order. For more help with the Report Generator and calculated channels or contact [email protected] ________________________________________________________ ________________________________________________________ * Copyright Windmill Software Ltd * Reprinting permitted with this notice included * For more articles see We are happy for you to copy and distribute this newsletter, and use extracts from it on your own web site or publication, providing the above notice is included and a link back to our website is in place. An archive of previous issues is at and an index of articles at Windmill Software Ltd, PO Box 58, North District Office, Manchester, M8 8QR, UK Telephone: +44 (0)161 833 2782 Facsimile: +44 (0)161 833 2190 E-mail: [email protected]


To receive Monitor every month please fill in your e-mail address below. We will not pass your address to any third parties, nor send you any unsolicited e-mail.


Previous Issue Next Issue