Windmill Software Ltd
Windows Engineering Software

Monitor
September 2006

-------------------------Monitor------------------------
The Newsletter for PC-Based Data Acquisition and Control
Issue 98          www.windmill.co.uk      September 2006
--------------------ISSN 1472-0221----------------------

Welcome to September's issue of Monitor: we hope you 
find it useful. Should you wish to cancel your 
subscription though you can do so at 
http://www.windmill.co.uk/newsletter.html

CONTENTS
========
* Windmill News: Data Acquisition Glosary Updated 
* Excel Corner: Resettting a Counter from Excel
* DAQ News Roundup
________________________________________________________
________________________________________________________

Windmill News: Data Acquisition Glosary Updated
________________________________________________________

Thank you to everyone who suggested terms that should be 
in our data acquisition glossary.  Here are some of 
the new inclusions.

Absolute accuracy
  How closely the measured value approaches the real 
  value.

Relative accuracy
  How accurately a change in signal is measured. 

Analogue Input
  An infinitely variable signal connected to a data 
  acquisition system.  This is generally a voltage 
  signal. Thermocouples, strain gauge bridge circuits 
  and gas concentration probes, for example, all 
  produce an analogue voltage.  Alternatively the 
  signal may be a milliamp current.  In this case 
  the data acquisition hardware will convert the 
  current to a voltage before accepting it. 

Analogue Output
  A waveform or control signal generated by the 
  data acquisition and control equipment. 

Digital Input
  A digital signal going into a data acquisition 
  device. A digital signal has only 2 states.  

Digital Output
  A digital signal generated by the data acquisition 
  and control equipment. Software controls each 
  digital output by just one bit - setting the 
  digital line high or low.

Calibration
  The process where a data acquisition device's 
  performance is compared to an accuracy standard, and 
  the performance adjusted as necessary.  

Current sink
  The maximum current that data acquisition output 
  channels can dissipate.

Current source 
  The maximum current that can be supplied by the 
  data acquisition device for output signals. 

Decibel
  A logrithmic measure of the ratio between 
  two quantities.  Symbol dB.

Dynamic range
  The ratio of the largest to the smallest signal that 
  can be measured at one time. Normally expressed in 
  Decibels (dB). The maximum signal is generally the 
  analogue-to-digital converter's full scale signal. 
  The dynamic range of a DAQ device is important when 
  both large and small signals are to be measured. 
  Dynamic Range = 20 x log (Max Voltage / Min Voltage)

RTU
  Remote Terminal Unit. A data acquisition device at 
  a remote location which transmits data back to, and 
  accepts commands from, a central PC (or other 
  controller).

TCP/IP
  Transmission Control Protocol/Internet Protocol. 
  Communications protocols used to connect hosts on the 
  internet. 

Text format
  Information in the ASCII character set that is 
  unformatted. Each byte in the file contains one 
  character that conforms to the standard ASCII code.

For the full glossary, with links to more information 
and articles, go to
http://www.windmill.co.uk/glossary.html
________________________________________________________
________________________________________________________

Excel Corner: Resetting a Counter from Excel
________________________________________________________

Windmill lets you use Excel to send commands to your 
data acquisition devices.  You can thus use Excel to 
reset a counter to zero.  How you do this depends on 
your counting equipment.

If you have a Microlink device, such as the USB units 
we sell in our on-line shop (www.windmillsoft.com), 
then you can reset a counter by sending it a 0.

If you have an instrument connected to the PC 
over RS232, then you can often reset a counter by 
sending it a command to do so.

                        *

To Reset a Microlink Counter....
================================

1. Start Windmill DDE Panel and select the Connections 
   menu. Make sure your counter is connected. 

2. In Excel enter a 0 into cell A1 and create 
   this macro.

   Sub DDEpoke()
   ddeChan = Excel.DDEInitiate("Windmill", "data")
   Excel.DDEpoke ddeChan, "counter", Range("A1")
   Excel.DDETerminate (ddeChan)
   End Sub

   Where "counter" is the name of your 
   counter channel.

3. Run the macro from Excel. The counter is reset to 0.

Note: You can't reset a Microlink 826 to 0.  This logs 
data from utility meters - sending the consumption 
readings to a PC running Windmill.

                        *

To Reset a Counter on an RS232 Instrument...
============================================

1. Install the free Windmill Software with the LabIML 
   driver or the Windmill CONFIML software 
   (http://www.windmill.co.uk/https://www.windmillsoft.com/daqshop/rs232-modbus.html).

2. With the free software, use ConfIML to configure 
   the driver. Create an extra channel to hold the 
   Reset command.

3. In ConfIML, go to the Channel settings dialogue.
   - Select your Reset channel and set it as a "Write  
     channel"
   - Type \V into the Write string box. When you run 
     your Excel macro, the \V will be replaced by 
     the reset command. If the command needs any 
     hidden characters, such as a Return, use the 
     non-printable button to insert these before or 
     after the \V
   - Save

4. Start SetupIML and create a setup file using the 
   configuration you have just saved.

5. Start Windmill DDE Panel, load the setup file and
   connect your counter.

6. In Excel, enter the command to reset the counter 
   into cell A1 and then create this macro

   Sub DDEpoke()
   ddeChan = Excel.DDEInitiate("Windmill", "data")
   Excel.DDEpoke ddeChan, "counter", Range("A1")
   Excel.DDETerminate (ddeChan)
   End Sub

   Where "counter" is the name of your 
   counter channel.

When you run the macro, the \V command you entered 
in ConfIML is replaced by whatever is in cell 
A1 in Excel.

For example, to reset a magnetometer counter you 
might have the command ARC followed by a carriage 
return. In ConfIML you would enter \V\C013 (\C013 
indicates the carriage return). In Excel you would 
enter ARC into cell A1. When you ran the macro the 
\V is replaced by ARC and is followed by the 
carriage return.

                        *

Note: If you prefer you can use the AnalogOut 
program instead of DDE Panel. In this case, for 
line 2 of your macro, use
ddeChan = Excel.DDEInitiate("AnalogOut", "data")

For more on using Excel for data acquisition and 
control, see 
http://www.windmill.co.uk/excel/
________________________________________________________
________________________________________________________

DAQ News Roundup
________________________________________________________

Welcome to our roundup of the latest findings in 
data acquisition and control.  If you would like to 
receive more timely DAQ news updates then grab our 
RSS newsfeed at 
https://www.windmillsoft.com/monitor.xml.  Read 
http://www.windmill.co.uk/newsfeed.php for notes
on how to display the news on your own web site, 
read it via e-mail or through a newsfeed viewer.

Swallowable Sensors
   An ingested wireless capsule that can help 
   clinicians diagnose digestive disorders is ready for 
   patients. The electronic pill is swallowed; it then 
   gathers information about the digestive system as it 
   travels through it, transmitting the information to a 
   receiver worn by the patient.
   Source: Technology Review
   http://www.technologyreview.com/

How-To Guide for Removing Data from Storage Media
   Before ditching or donating that used computer, CD 
   or other data-storage media, sensitive or personal 
   information should be properly "sanitised," according 
   to a new guide from the National Institute of 
   Standards and Technology (NIST).  The Guide provides 
   information on techniques to remove data from a wide 
   variety of media types and a decision matrix to 
   determine which technique is best. 
   Source: National Institute of Standards and Technology
   https://www.nist.gov/

New sensor system detects ocean pollution
   A new technique developed by UC Irvine scientists 
   mathematically analyses temperature and salinity 
   data collected by sensors in the water along the 
   coast.  The scientists found that fluctuations in 
   the sensor data immediately correlate with changes 
   in water quality.  This is a far faster way of 
   detecting pollution than collecting water samples.  
   The researchers' equations transform the data into 
   a measurement of the range over which the data 
   naturally fluctuates, and thus immediately flag 
   pollution.
   Source: University of California, Irvine
   http://today.uci.edu/news/release_detail.asp?key=1525

Taking measurements inside a hurricane
   A small aircraft is set to fly through the eye of 
   a hurricane to take the first continuous data on how 
   such storms gain their strength. 
   The craft, called an aerosonde, will measure the 
   temperature, pressure, humidity and wind velocity 
   inside the storm in an effort to help predict 
   changes in hurricane intensity.
   Source:  NewScientist.com news service
   http://www.newscientistspace.com/
________________________________________________________
________________________________________________________

* 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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