Windmill Software Ltd
Windows Engineering Software

February 2005

The Newsletter for PC-Based Data Acquisition and Control
Issue 79       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

* 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

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 

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 

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 

All contiguous cells will be selected.

Further Reading
For tips on using Excel with Windmill see

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.

  17-20 March 2005
  Istanbul Turkey
  Industrial automation fair.

  5-8 April 2005
  Warszawa Poland
  International fair for measurement and control.

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.

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.

  10-12 May 2005
  Nuremberg Exhibition Centre Germany
  Measuring systems from microsensors to complex test 

National Manufacturing Week 
  10-13 May 2005
  Melbourne Australia
  Includes engineering, pneumatics, hydraulics, safety 
  products, machine tools, materials handling, assembly, 
  computers, process and control.

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

  Mexico DF, Mexico
  15-17 Jun 2005
  Covers sensors, transmitters, robotics, 
  instrumentation and control systems.

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

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]


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