Windmill Software Ltd
Data Acquisition Intelligence

August 2011

The Newsletter for PC-Based Data Acquisition and Control
Issue 157         August 2011
--------------------ISSN 1472-0221----------------------

Welcome to Monitor, the newsletter for data acquisition 
and control.  This month we are slashing the price of 
strain measurement from £775 to £475, that's 770 USD or 
540 Euro. Read below for more information or visit

We hope you find the newsletter useful, but should you 
wish to remove yourself from our mailing please go to 
Monitor Newsletter

* Windmill News: Strain Gauge Package Reduced
  - 5 Tips on Measuring Strain
  - Digital Inputs, Outputs and Counters
  - Windows Software
  - Technical Support
* DAQ News Round-up
* Data acquisition and control exhibitions

Windmill News: Strain Gauge Package Reduced

Windmill's 751-SG package has 16 channels with which you 
can monitor strain gauges, balanced bridges like pressure 
transducers and voltage signals. This USB unit also 
provides 32 digital inputs and outputs and 8 counters. 
Connect eight units to one PC and monitor 128 strain gauges.

We have cut the cost of this easy-to-use strain 
measurement system by £300 at our on-line catalogue:

Measuring Strain

Here are five points to consider when choosing a strain 
measurement system. 

1. The initial unstrained  measurement is often much larger 
   than the change in signal due to strain. If this initial 
   value is not accounted for, it restricts the resolution 
   you can obtain - that is the smallest signal you can 

   The 751-SG system zeroes or balances the strain gauge 
   bridge, nulling the offset of the initial voltage. So 
   instead of measuring over a wide range, 0 to 0.5 V for 
   example, you can choose a narrow range such as 0 to 0.01 V. 

2. Each range is divided into a fixed number of steps: the 
   resolution. The smaller the range and the greater the 
   resolution, the more precise the reading. The 751-SG 
   offers a choice of resolutions from 12-bit for fast 
   sampling to 18-bit for greater precision.

3. You need to apply an excitation voltage which supplies 
   sufficient current to keep all the bridge circuits 
   energised. The 751-SG package provides excitation 
   for each of 16 Wheatstone bridges. 

4. Measured changes may not only be due to the changes 
   in strain. Other factors might also affect the reading, 
   such as a change in the excitation voltage. This is 
   of especial concern in long-term measurements where 
   component values may drift with time and temperature. 

   With the 751-SG, when a bridge input is selected 
   the Windmill Software automatically monitors the 
   excitation voltage and performs the bridge 
   calculation to produce a reading in microstrain. 
   This eliminates errors due to changes in 
   excitation voltage. 

5. The changes in voltage due to strain are tiny: 
   measured in microvolts. Monitoring such small 
   signal changes can often produce jitter in the 
   readings from noise. For slow sampling you can 
   counteract this with an integrating analogue-to-
   digital converter. By averaging the signal over 
   50 or 60 Hz the noise is rejected. 

Analogue Inputs

You can configure each of the 751-SG's 16 analogue 
input channels to accept any of these inputs:
- voltage 
- quarter bridge: single strain gauge 
- half bridge: tensile + compressive strain gauge 
- half bridge: normal + transverse strain gauge 
- full bridge: 2 tensile + 2 compressive gauges 
- full bridge: 2 normal + 2 transverse gauges 
- full bridge: tensile normal + compressive normal 
  + tensile transverse + compressive transverse gauge

Digital Inputs, Outputs and Counters

The 751-SG provides 32 digital I/O lines, arranged 
in four groups of 8. One group of 8 lines can also 
be used to count. Each counter starts at zero and 
counts pulses to a maximum of 65535. 

You can reset a counter at any time from Windmill 
software. You can use the counters in two modes: 
accumulating count and resetting count. In 
accumulating count the counter keeps counting until 
you reset it. In resetting count the counter shows 
the number of pulses since the last reading.

Windows Software

Windmill Software is included in the 751-SG package. 
This modular suite offers data logging, charting, 
alarm monitoring, output control and real-time links 
to other applications like Excel.  Windmill runs under 
Windows 10, 8, 7 64-bit and all other versions down to 
Windows 95.

Technical Support

Should you need any advice on setting up your system 
we are happy to help by phone or e-mail. This 
unlimited service is included in the price and 
lasts a lifetime.

For more information e-mail [email protected], 
telephone +44 (0)161 833 2190 or visit

Further Reading
A tutorial on Measuring Strain is at

DAQ News Round-up

Welcome to our round-up of the data acquisition and 
control news.  If you would like to receive more 
timely DAQ news updates then either grab our RSS 
newsfeed at 
follow us on Twitter at!/DataAcquisition

Sensors Harvest Energy from Vibration to Keep unning
   Tiny sensors can now harvest constant power from 
   vibration instead of using batteries.  MicroGen Systems 
   and Cornell University have collaborated to develop 
   battery-free sensors that can operate in anything that 
   spins, rolls, jiggles or shakes, like car tires and 
   clothing dryers.
   Source: Cornell University

Measuring bacterial heat could reduce cost of diagnosing TB
   Researchers in Switzerland hope to reduce the time and 
   cost of diagnosing tuberculosis by measuring the heat 
   bacteria produce as they grow.  A team is developing a 
   method using microcalorimeters, which produce unique 
   electrical signals based on the heat given off by 
   different chemical, physical or biological processes.
   Source: The Engineer

Tests Help Ensure Reliable Wireless Alarm Beacons for First Responders
   Wireless emergency safety equipment could save 
   lives-if signals are transmitted reliably. But few 
   performance standards exist. Now, tests at the National 
   Institute of Standards and Technology (NIST) are 
   helping to ensure that alarm beacons for firefighters 
   and other emergency responders will operate reliably 
   in the presence of other wireless devices.
   Source: NIST

Electronic 'tongue' could identify types of Cava
   Researchers at Universitat Autonoma de Barcelona 
   have developed an electronic tongue which can 
   identify different types of cava wines, thanks to 
   a combination of sensor systems and advanced 
   mathematical procedures. The device automatically 
   produces classifications similar to those of a sommelier.
   Source: UAB

Data Acquisition Exhibitions and Conferences

Our quarterly update of data acquisition and control 
exhibitions around the world.

Automation Vietnam
15-17 September
Hanoi Vietnam
Automation and assembly technologies. Features technology 
presentations to impart new knowledge to participants.

Automation 2011
20-23 September 2011
Mumbai India
Factory automation, robotics, drives and controls, 
building automation and software solutions. It is termed 
as India's biggest Automation show of the year.

Sensing Technology
27-28 September 2011
Birmingham UK
Test, measurement, instrumentation.

4-6 October 2011
Paris France
France's research, testing and industrial 
instrumentation exhibition.

Smart Automation Austria 2011
4-6 October 2011
Linz Austria
Trade fair for industrial automation.

5-7 October 2011
Milan Italy
Complete showcase of products, technologies, 
processes and instrumentation, including manufacturing 
and processing machinery, equipment and components; 
equipment, instrumentation and materials for the 
laboratory and process; testing, control and automation 
technologies and instrumentation.

Controls Instrumentation and Automation 2011
22-25 November
Showcases the latest technologies catering to the 
process engineering demands in the Chemical, Food, 
Petroleum/Energy, Waste and Water industries.

* 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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