-------------------------Monitor------------------------ The Newsletter for PC-Based Data Acquisition and Control Issue 120 www.windmill.co.uk July 2008 --------------------ISSN 1472-0221---------------------- Welcome to Monitor. I hope you enjoy the newsletter but if you want to remove yourself from our mailing list please do so at http://www.windmill.co.uk/newsletter.html CONTENTS ======== * Windmill Notes: Comparing Serial Driver Software * Communicating with RS232 Instruments: ASCII Character Codes * DAQ News Roundup ________________________________________________________ ________________________________________________________ Windmill Notes: Comparing Serial Driver Software ________________________________________________________ Windmill offers two serial drivers: COMIML and LabIML. Both of these collect data from instruments and devices connected to the PC's COM port. LabIML is part of the Windmill 4.3 suite of data acquisition and control software and is free (to Monitor subscribers). COMIML is part of the Windmill 6 suite of software and a free trial is available from www.windmillsoft.com So what are the differences between the two? * Communications Supported * COMIML works with RS232, RS422, RS485 and Modbus instruments; LabIML only works with RS232 instruments * Data Formats * COMIML supports ASCII and Binary formats; LabIML only understands data in ASCII format * Number of Instruments that can be Connected * COMIML can handle up to 10 instruments connected to the PC at once; LabIML can only handle 4 instruments * Operating System * COMIML runs under Windows 95, NT, 98, 2000 and XP; LabIML runs under Windows 95, NT, 98 and 2000 * Error Checking * COMIML lets you see and control the state of the COM port lines; LabIML doesn't have this facility * Technical Support * Both programs have free technical support for life Further Reading =============== COMIML www.windmillsoft.com LabIML http://www.windmill.co.uk/rs232.html ________________________________________________________ ________________________________________________________ Communicating with RS232 Instruments: ASCII Character Codes ________________________________________________________ When you communicate with an instrument over RS232, you often have to send it a string of characters. It is not always obvious how to enter some of these but this table should help. For instance, when a carriage return is needed you enter decimal 013 or hexadecimal 0D into your serial communications software - ComDebug or LabIML for example. Char Ctrl Dec Hex Meaning NUL ^@ 000 00 Null character SOH ^A 001 01 Start of Header STX ^B 002 02 Start of Text ETX ^C 003 03 End of Text EOT ^D 004 04 End of Transmission ENQ ^E 005 05 Enquiry ACK ^F 006 06 Acknowledge BEL ^G 007 07 Bell BS ^H 008 08 Backspace HT ^I 009 09 Horizontal tab LF ^J 010 0A Line feed VT ^K 011 0B Vertical tab FF ^L 012 0C Form feed CR ^M 013 0D Carriage return SO ^N 014 0E Shift out SI ^O 015 0F Shift in DLE ^P 016 10 Data link escape DCL ^Q 017 11 Xon DC2 ^R 018 12 Device control 2 DC3 ^S 019 13 Xoff DC4 ^T 020 14 Device control 4 NAK ^U 021 15 Negative acknowledge SYN ^V 022 16 Synchronous idle ETB ^W 023 17 End of transmission CAN ^X 024 18 Cancel EM ^Y 025 19 End of medium SUB ^Z 026 1A Substitute ESC ^[ 027 1B Escape FS ^\ 028 1C File separator GS ^] 029 1D Group separator RS ^^ 030 1E Record separator US ^_ 031 1F Unit separator SP 032 20 Space Notes: The Char column above shows the ASCII codes. Originally these were used for teleprinters, so many of the codes are now obsolete. Carriage Return, Line Feed and Escape are the three that you will most often come across. Also look out for STX and ETX which are used to mark the start and end of messages from instruments. The Ctrl column shows how the ASCII characters might be entered on a keyboard or using the instrument's front panel. ________________________________________________________ ________________________________________________________ DAQ News Roundup ________________________________________________________ Welcome to our roundup of the data acquisition and control news. If you would like to receive more timely DAQ news updates then grab our RSS newsfeed at https://www.windmillsoft.com/monitor.xml. Read http://www.windmill.co.uk/newsfeed.php for notes on how to display the news on your own web site, read it via e-mail, mobile phone or a newsfeed viewer. Study highlights data acquisition trends A recently completed study from Venture Development Corporation (VDC) found a trend towards higher resolution in A/D converters. Most shipments currently have A/D converters with 12- or 16-bit resolution: VDC forecasts this to change. Many purchasers seem to equate resolution directly with accuracy – reasoning that the better the resolution, the higher the accuracy. Thus, if they can afford the higher resolution units, they will purchase these. Declining prices for the higher resolution products are helping this trend. Another shift is to equipment with more input channels. (Note: for an explanation of resolution and accuracy see Monitor # 95.) Source: Venture Development Corporation http://www.vdcresearch.com/? Synchronising 'heartbeat' saves sensor batteries "Pumping" data around a wireless network of sensors - just as blood is pumped around the human circulatory system - could allow the sensors' batteries to last four times as long. Sensor networks are usually "tree-like". Their branching structure means information gets from A to B quickly, but means devices have to be turned on permanently to co-ordinate the data traffic. A new system that synchronises the flow of information from node to node around the network. Nodes only turn on when the beat reaches them, saving battery power - but the system is slow because data has to travel all the way around the network. Source: New Scientist https://www.newscientist.com/ Saving Energy in Buildings Adopting currently available technologies could reduce annual CO2 emissions in London by nearly 44 percent. Almost 70 percent of the potential abatement could be achieved with the help of technologies that would pay for themselves, largely by reducing energy costs, according to a study by McKinsey. The biggest saving potential lies in buildings: measures such as building automation systems and insulation could reduce London's emissions by a third by 2025. Source: Siemens http://w1.siemens.com/ Low energy X-rays inspect food New inspection X-ray technology developed by European researchers is helping to ensure that the only thing in people's dinners is the food itself. The technology uses low-energy X-rays to produce highly detailed images of food products and packaged goods. The images are then scanned via inspection software that can automatically detect any irregularities accurately and quickly. The system can be used to check seals on food wrappers, locate packaging defects and find foreign particles of any size in any kind of food, from maggots in apples to grains of sand in bread. Source: ICT Results http://cordis.europa.eu/ictresults/ ________________________________________________________ ________________________________________________________ * 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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