-------------------------Monitor------------------------ The Newsletter for PC-Based Data Acquisition and Control Issue 79 www.windmill.co.uk February 2005 --------------------ISSN 1472-0221---------------------- Welcome to Issue 79 of Monitor. We hope you find it useful, but should you wish to cancel your subscription to Monitor you can do so at http://www.windmill.co.uk/newsletter.html CONTENTS ======== * Windmill News: Survey Thanks * Data Logging Techniques * Excel Corner: Quickly Selecting Tables * Data Acquisition Exhibitions and Conferences ________________________________________________________ ________________________________________________________ Windmill News: Survey Thanks ________________________________________________________ Thank you to everyone who filled in last month's survey. My apologies if you did so and haven't yet received a reply. I'm working through them all and will get back to you shortly. If you haven't yet completed our very short survey (only two questions) please do so at http://www.windmill.co.uk/monitor78.html ________________________________________________________ ________________________________________________________ Data Logging Techniques ________________________________________________________ What is Data Logging? ===================== Data logging is making measurements and recording them against time. You could, in some cases, do this by hand. But for increased speed and accuracy, in hostile environments, with unattended monitoring or logging over long periods of time - you need electronic data logging. * How to Electronically Log Data ============================== One method is with a stand-alone data logger, which you later plug into a computer to access the data. Alternatively you can use the PC itself as a data logger. The list of measurements that can be computerised is almost endless: temperature, pressure, strain, position, depth, rainfall, salinity, humidity, flow, pH, vibration, windspeed and so on. Using the PC as a data logger means a more flexible system with a real-time view of data trends via charts, tables or other displays. It also allows automatic control should set limits be exceeded. For example, if a temperature reached a certain level then a heater could be turned off. There are many ways to connect measuring devices to the PC. Some instruments, such as GPS receivers and electronic balances, can be plugged directly into the COM port of the computer. Sensors such as thermocouples or strain gauges might connect to units external to the PC, communicating over USB, Ethernet, RS485, RS422, Modbus, GPIB or WiFi. An important component of the system is the software. At the very least you need a driver to communicate with the measuring device and some data logging software. With a PC, though, there are many more options available: software chart the data, monitor alarms, control a system, analyse the data, create reports and share information across networks. * Data Logging Software ===================== One thing to consider when choosing data logging software is how will the data be stored. A common solution is in ASCII text files. The file usually has the time, or time and date, in the first column followed by columns of the collected data: temperature, pressure, etc. You can read this type of file in most spreadsheets, word processors or other reporting or analysis software. However, ASCII files are inefficient in their use of disk space, and the logger software takes a relatively long time to create them. They are suitable for low speed data logging (say 100 samples per second). Windmill Logger stores data in ASCII format When high speed logging is needed data may be stored in binary format. This uses less space than ASCII and writing to disk is quicker. Some software can use ASCII files even in high speed applications. It does this by storing the data in memory until collection is complete, and then converting the data to the appropriate engineering units and storing to disk. However, because data is stored in memory it limits the amount of data that can be collected in any one go. Windmill Streamer can log data at high speed in binary or ASCII format. Applications like Excel cannot read binary files, you need some specialise software to analyse or convert the data, such as Windmill Review. * Further Reading =============== Choosing a Data Acquisition System Data Logging Applications Product Testing Logging Temperature Logging Strain Weather Monitoring Logging from NMEA Instruments Connection Options ________________________________________________________ ________________________________________________________ Excel Corner: Quickly Selecting Tables ________________________________________________________ To quickly select an entire table of data: 1. Click inside the table 2. Press the Ctrl key together with the * key on the keypad All contiguous cells will be selected. Further Reading =============== For tips on using Excel with Windmill see http://www.windmill.co.uk/excel/ ________________________________________________________ ________________________________________________________ Data Acquisition Exhibitions and Conferences ________________________________________________________ Our quarterly list exhibitions around the world dedicated to data acquisition and control. National Manufacturing Week 7-10 March 2005 Chicago Illinois USA Includes industrial automation and design engineering. http://www.manufacturingweek.com/ OTOMASYON 17-20 March 2005 Istanbul Turkey Industrial automation fair. http://www.bilesim.com.tr/ AUTOMATICON 5-8 April 2005 Warszawa Poland International fair for measurement and control. http://www.automaticon.pl/ Hannover Fair 11-15 April 2005 Hannover, Germany A presentation of industrial automation technology worldwide. The show brings together eleven trade fairs, including Interkama and Factory Automation. http://www.hannovermesse.de/ Test and Measurement China 2004 12-15 April 2005 Shanghai China The exhibition encompasses test and measurement equipment such as meters, bare board testers, optical inspection system, circuit testers, x-ray equipment, test fixtures, etc. http://www.nepconchina.com/ SENSOR+TEST 2005 10-12 May 2005 Nuremberg Exhibition Centre Germany Measuring systems from microsensors to complex test rigs. http://www.sensor-test.de/main/dpgh71tn/page.html National Manufacturing Week 10-13 May 2005 Melbourne Australia Includes engineering, pneumatics, hydraulics, safety products, machine tools, materials handling, assembly, computers, process and control. http://www.reedexhibitions.com.au/ Sensors Expo and Conference 2005 6-9 June McCormick Place Lakeside Center Chicago USA Dedicated to exploring the most up-to-date innovations in sensor technology including physical sensors, sensor networks, biosensors, MEMS/nanotechnology, instrumentation and controls, intelligent systems, machine-to-machine communication, wireless sensing and IT technology http://www.sensorsexpo.com/spring04/V41/index.cvn ISA EXPO CONTROL Mexico DF, Mexico 15-17 Jun 2005 Covers sensors, transmitters, robotics, instrumentation and control systems. http://www.isamex.org/ Process Control, Instrumentation and Metrology 2005 Bangkok, Thailand 16-19 June 2005 International exhibition and conference for process control and instrumentation, measurement, test, calibration equipment and quality control ________________________________________________________ ________________________________________________________ * 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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