------------------------Monitor------------------------- The Newsletter for PC-Based Data Acquisition and Control Issue 38 www.windmill.co.uk September 2001 --------------------ISSN 1472-0221---------------------- Welcome to Issue 38 of Monitor. We hope you enjoy it but should you wish to cancel your free subscription please visit http://www.windmill.co.uk/newsletter.html CONTENTS ======== * Windmill News: New Version of Trouble-Shooting Software for Serial Communications * Data Acquisition News: Emissions Trading * Excel Corner ________________________________________________________ ________________________________________________________ Windmill News: New Version of Trouble-Shooting Software for Serial Communications ________________________________________________________ A new version of ComDebug, the serial communications software for RS232, RS422, RS485 and Modbus devices, is now available free to our readers. The new version integrates more seamlessly into a Windmill system and corrects the mixing up of the odd and even parity. With ComDebug you can control the majority of serial instruments, including those from Bruel and Kjaer, Mettler Toledo, Microchip, Motorola, Molytek, Omron, Parallax, Sartorius, Siemens and Texas Instruments. For more details, and to download your free copy, visit http://www.windmill.co.uk/serial.html ________________________________________________________ ________________________________________________________ Data Acquisition News: Emissions Trading ________________________________________________________ Last month the British Government launched the world's first greenhouse gas trading scheme. Briefly, companies can volunteer for the scheme by agreeing an emissions reduction in return for a financial incentive. This is good news for data acquisition companies like ourselves, who produce emission and energy monitoring software. The government has promised 215m pounds, over 5 years from 2003, for the incentive payments. They plan to set the targets and incentives through a bidding process in January. Those failing to reach their emission reduction targets will have to pay back the incentive money with interest, and will face tougher targets in future years to make up the shortfall. Although this scheme is heralded as the first for greenhouse gas trading, the United States already operates a similar system to control sulphur dioxide and nitrogen oxide. Other initiatives are being considered in France, Canada, Australia and Germany. It is likely that the UK scheme will ultimately be merged into a European Union trading plan, a pilot of which is due to begin in 2005. More Information: More details of the UK scheme. Issue 6 of Monitor discussed emission monitoring. ________________________________________________________ ________________________________________________________ Excel Corner: Calculating Average Values and Standard Deviation for Live Data ________________________________________________________ We were recently asked how to get running averages and standard deviations for live data. Here's the answer. 1. You need an Excel macro to acquire live data, where each set of readings is placed in the next empty row. For an example of such a macro see our web site http://www.windmill.co.uk/excel/ 2. Edit the macro so that instead of the first set of data being placed in the first row, it is placed in the third row. In our example macro change: "NoOfRows = 1" to "NoOfRows = "3" and "While NoOfRows < NoOfSamples + 1" to "While NoOfRows < NoOfSamples + 3" 3. Each channel's data (temperature, strain or humidity for instance) is stored in a column. Enter the Average formula for the data in Row 1 and the Standard Deviation formula in Row 2. If you were collecting 20 data readings for one channel, for example, you'd have AVERAGE(A3:A23) and STDEV(A3:A23). 4. Start Windmill DDE Panel. 5. Run the Excel macro. You will be asked how many samples (sets of data) you want to collect. Twenty in our example. You will also be asked the interval between samples. Excel will then read data from all your channels. As each row of data is added, the average and standard deviation for each channel is updated * Indicating Alarms when Average Levels are Exceeded ================================================== You can tell Excel to indicate whether the current averages are outside test limits. Simply use an IF statement. For example IF(A2>30,"Alarm","OK") Here A2 contains the average calculation and 30 is the test limit. If A2 is over 30 Excel shows "Alarm", otherwise it shows "OK". This is fine if you are looking at the Excel screen. However, if you are collecting a large number of samples, or over a long time scale, you may prefer to have a permanent record of alarm conditions. Our Windmill Blackboard program lets you send your averages, standard deviations and any other calculated values back to the Windmill system, where they can be logged alongside the raw data. For more details contact Windmill Software, [email protected] ________________________________________________________ ________________________________________________________ * Copyright Windmill Software Ltd * Reprinting permitted with this notice included * For more articles see http://www.windmill.co.uk 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 http://www.windmill.co.uk/newsletter.html and an index of articles at http://www.windmill.co.uk/newsletter.html 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] http://www.windmill.co.uk/ https://www.windmillsoft.com/
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