Windmill Software Ltd
Data Acquisition Intelligence

November 2011

The Newsletter for PC-Based Data Acquisition and Control
Issue 160        November 2011
--------------------ISSN 1472-0221----------------------

Welcome to November's newsletter. This month we welcome 
the return of the Excel corner, with tips on entering data. 
Our Windmill news is that we've redesigned our 
thermocouple monitoring hardware to make for a more 
compact system. 

Our next issue will feature an article on data acquisition 
over TCP/IP, and news of free logging software for 
Ethernet and Internet devices. 

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

* Windmill News: Windmill Redesign Thermocouple Monitor
* Excel Corner: Speedy Formula Updates
* DAQ News Round-up

Windmill News: Windmill Redesign Thermocouple Monitor

Thermocouples are popular temperature sensors because 
they are cheap, versatile and sturdy. They comprise
two dissimilar metals joined together, making a 
continuous circuit. If one junction has a different 
temperature to the other, an electromotive force 
(voltage) is set up. This voltage varies with the 
temperature difference between the junctions.  If the 
temperature at one junction is known, the temperature 
at the other junction can be calculated. 

Our new, compact, 593 unit is an isothermal box for 
accurate monitoring of one of the junctions of the 
thermocouples. The insulated 593 holds a cold junction 
sensing RTD (resistance temperature device) with an 
associated constant current source (0.8 milliamps). 

The RTD measures the temperature at the thermocouple's 
termination point.  This reference temperature is used 
with the analogue input channel's voltage reading to 
calculate the required temperature. 

The cold junction is automatically connected to an 
auxiliary channel on the data acquisition unit (for 
example a 751 or 752 unit) and compensated for in 
software.  The channel is read directly showing the 
cold junction temperature in Celsius, or in your 
preferred temperature units.

The 593 also offers protection from high voltages 
when series resistors are fitted.  Noise problems 
can be solved by fitting an input filter and 
broken thermocouple leads can be detected.  It is 
easily connected to the data acquisition unit with 
a ribbon cable.

Further Reading:
593 Thermocouple Connection Box

Computerised Temperature Measurement

Excel Corner: Speedy Formula Updates

When setting up a column of calculations, most of us 
simply drag the top-most entry down.  However, you can 
use a much more efficient method: Excel's "data table".  
This is especially useful if the formula you have 
entered is likely to change.

For example, column A contains a list of weights in 
grams.  Column B converts these weights from grams to 
kilograms, using the formula A*1000.  You later decide 
you want the data not in kilograms but in milligrams.  
To do this using a data table:

1. Select Columns A and B, to the extent of your data.
2. From the Data menu select Table.  A box appears.

3. Enter the top data cell into Column input cell, eg A1.
   Leave the Row input cell blank. Press OK.
4. If Cell B1 is empty then a list of zeroes are shown 
   in column B
5. In cell B1 enter your formula. The results are shown 
   throughout the column: no clicking and dragging needed. 

Now if you change the formula in cell B1 it will be 
changed throughout the column.

For more tips on using Excel see

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

New Report Urges More Detailed Utility Metering to Improve Building Efficiency
   A new report recommends systematic consideration of 
   new metering technologies that can yield up-to-date, 
   finely grained snapshots of energy and water usage 
   in buildings to guide efficiency.
   Source: NIST

Study Shows Business Case for Industrial Ethernet
   A report by the Aberdeen group shows that best-in-
   class manufacturers are deploying industrial 
   Ethernet across plants to improve network, operational 
   and corporate performance.
   Source: Aberdeen Group

Researchers develop steering wheel with health sensors
   A Munich-based research team has developed a steering 
   wheel embedded with sensors to monitor the health 
   of drivers.
   Source: The Engineer

Magnetic tongue to produce tastier tinned tomatoes
   A "magnetic tongue" can predict the taste of tinned 
   tomatoes. The sensor could help food manufacturers 
   tweak their production methods to maximise flavour.
   Source: New Scientist

* Copyright Windmill Software Ltd
* Reprinting permitted with this notice included
* For more articles see

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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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