Windmill Software Ltd
Windows Engineering Software

Monitor
September 2003

-------------------------Monitor------------------------
The Newsletter for PC-Based Data Acquisition and Control
Issue 62          www.windmill.co.uk      September 2003
--------------------ISSN 1472-0221----------------------

Hello, and welcome to the September issue of Monitor
 - 
the newsletter for PC-based data acquisition and 
control. We only send Monitor to people who have 
subscribed - should you wish to cancel your subscription 
please do so at 
http://www.windmill.co.uk/newsletter.html

CONTENTS
========
* Windmill News: Improved Crash Testing for Cars
* Excel Corner: Automatically Updating a Chart
________________________________________________________
________________________________________________________

WINDMILL NEWS: IMPROVED CRASH TESTING FOR CARS
________________________________________________________

Crash testing is essential to ensure passenger safety.  
The Britax Excelsior crash testing facility at Andover 
(UK) has two tracks which it uses to test its car and 
aircraft seats.  Recently Britax has conducted a major 
upgrade to its facility and Windmill Software has 
been closely involved in this.

In order to provide calibration and online viewing of 
the output from accelerometers, Windmill produced a 
driver for the Microlink 580 transient capture card that 
Britax was already using.  This meant engineers could 
now view readings in the Windmill DDE panel.

Windmill also modified their Brake Testing application 
to provide a front end software package that allows the 
operator to select a particular type of test and dummies 
to be used. These are associated with particular sensors 
so that calibration data for each sensor is 
automatically passed to the analysis program (FAMOS).  
FAMOS can then give accurate readings of acceleration in 
g (grav).  

The setup of the test, data collection during the crash, 
and analysis according to the test selected are all
processed through the Windmill front end software.  
This maintains records of each test carried out, 
together with storage of raw data files for later 
re-analysis if required.

FAMOS sequences have been produced that extract the 
crash test waveforms, filter these according to the 
international standards, and compare maximum 
accelerations in 3 axes for head and chest 
accelerometers, with additional rotational accelerations 
recorded for neck sensors.  FAMOS Sequences have also 
been provided to calculate the Head Injury Criteria 
(HIC) which finds the maximum of integrated head 
acceleration during the crash.

For more information contact Windmill Software at 
[email protected]
For more on Microlink Measurement and 
Control systems see http://www.microlink.co.uk/
________________________________________________________
________________________________________________________

EXCEL CORNER: AUTOMATICALLY UPDATING A CHART
________________________________________________________

When using Excel to display data from Windmill in real-
time, you may find it useful to also automatically 
update a chart in Excel.

Suppose you wanted to plot data in column A against the 
data in column B.  You could simply insert a chart with 
the range 

=$A:$B

As the data arrives from Windmill DDE Panel, the chart 
will automatically update. However, if the rows of data 
exceed the original size of the worksheet, the chart 
will stop.

You can get round this by using Excel's CountA and 
Offset functions. CountA gives you the number of non-
blank cells in a column.  With Windmill data this 
equates to the number of rows of data (and headings).  
Offset returns a cell reference according to your 
settings.  Using CountA as the height of the column 
gives a reference to the bottom row.  This reference 
will automatically update when new data arrives.

For example, this is the syntax of Offset: 
OFFSET(reference, rows, cols, height, width)
which becomes:
OFFSET(Sheet1!$A$1,0,0,COUNTA(Sheet1!$A:$A))
(assuming your data is in a worksheet called "Sheet1").

To implement this, using our previous example of 
plotting column A against column B.

1. Create 2 named ranges called ColA and ColB (for    
   example). 
   For Column A, from the Insert menu choose Name then 
   Define. In the names box type ColA and 
   in the Refers to box type 
   =OFFSET(Sheet1!$A$1,0,0,COUNTA(Sheet1!$A:$A))
   Press Add
   For Column B, in the names box type ColB and in the 
   Refers to box type 
   =OFFSET(Sheet1!$B$1,0,0,COUNTA(Sheet1!$B:$B))
   Press Add and close the dialogue box.

2. Insert a chart plotting Column A against Column B.

3. We now need to edit the chart so it automatically 
   updates.  Select the chart, right-click the 
	 plotted data series and select Source Data. Replace 
	 the current X Values with
   =Sheet1!ColA
   Replace the Y values with =Sheet1!ColB
   (In the in the formula bar this will look like: 
   =SERIES(,Sheet1!ColA,Sheet1!ColB,1)

3. Click off the chart and start importing data into 
   Excel.  The chart will continually update no matter how 
   many rows of data you collect.

For details of getting live data from Windmill into 
Excel, see
http://www.windmill.co.uk/excel/
For more on charting with Excel see
http://www.windmill.co.uk/excel/excel-charting.html
________________________________________________________

* 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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