Windmill Software Ltd
Data Acquisition Intelligence

July 2008

The Newsletter for PC-Based Data Acquisition and Control
Issue 120          July 2008
--------------------ISSN 1472-0221----------------------

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* Windmill Notes: Comparing Serial Driver Software
* Communicating with RS232 Instruments: ASCII 
  Character Codes 
* DAQ News Roundup

Windmill Notes: Comparing Serial Driver Software

Windmill offers two serial drivers: COMIML and LabIML.  
Both of these collect data from instruments and devices 
connected to the PC's COM port.

LabIML is part of the Windmill 4.3 suite of data 
acquisition and control software and is free (to Monitor 

COMIML is part of the Windmill 6 suite of software and a 
free trial is available from

So what are the differences between the two?

* Communications Supported *
  COMIML works with RS232, RS422, RS485 and Modbus 
  instruments; LabIML only works with RS232 instruments

* Data Formats *
  COMIML supports ASCII and Binary formats; LabIML only 
  understands data in ASCII format

* Number of Instruments that can be Connected *
  COMIML can handle up to 10 instruments connected to the 
  PC at once; LabIML can only handle 4 instruments

* Operating System *
  COMIML runs under Windows 95, NT, 98, 2000 and XP; 
  LabIML runs under Windows 95, NT, 98 and 2000

* Error Checking *
  COMIML lets you see and control the state of the 
  COM port lines; LabIML doesn't have this facility

* Technical Support *
  Both programs have free technical support for life

Further Reading



Communicating with RS232 Instruments: 
ASCII Character Codes 

When you communicate with an instrument over RS232, you 
often have to send it a string of characters. It is not 
always obvious how to enter some of these but this table 
should help. For instance, when a carriage return is 
needed you enter decimal 013 or hexadecimal 0D into 
your serial communications software - ComDebug or LabIML 
for example.

Char	Ctrl	Dec   Hex   Meaning
NUL	 ^@     000   00    Null character
SOH	 ^A     001   01    Start of Header
STX	 ^B     002   02    Start of Text
ETX	 ^C     003   03    End of Text
EOT	 ^D     004   04    End of Transmission
ENQ	 ^E     005   05    Enquiry
ACK	 ^F     006   06    Acknowledge
BEL	 ^G     007   07    Bell
BS	 ^H     008   08    Backspace
HT	 ^I     009   09    Horizontal tab
LF	 ^J     010   0A    Line feed
VT	 ^K     011   0B    Vertical tab
FF	 ^L     012   0C    Form feed
CR	 ^M     013   0D    Carriage return
SO	 ^N     014   0E    Shift out
SI	 ^O     015   0F    Shift in
DLE	 ^P     016   10    Data link escape
DCL	 ^Q     017   11    Xon
DC2	 ^R     018   12    Device control 2
DC3	 ^S     019   13    Xoff
DC4	 ^T     020   14    Device control 4
NAK	 ^U     021   15    Negative acknowledge
SYN	 ^V     022   16    Synchronous idle
ETB	 ^W     023   17    End of transmission
CAN	 ^X     024   18    Cancel
EM	 ^Y     025   19    End of medium
SUB	 ^Z     026   1A    Substitute
ESC	 ^[     027   1B    Escape
FS	 ^\     028   1C    File separator
GS	 ^]     029   1D    Group separator
RS	 ^^     030   1E    Record separator
US	 ^_     031   1F    Unit separator
SP	        032   20    Space

The Char column above shows the ASCII codes.  Originally 
these were used for teleprinters, so many of the codes 
are now obsolete. Carriage Return, Line Feed and Escape 
are the three that you will most often come across.  Also
look out for STX and ETX which are used to mark the start 
and end of messages from instruments.

The Ctrl column shows how the ASCII characters might be 
entered on a keyboard or using the  instrument's 
front panel.

DAQ News Roundup

Welcome to our roundup of the data acquisition and 
control news.  If you would like to receive more 
timely DAQ news updates then grab our RSS newsfeed 
at  Read for notes
on how to display the news on your own web site, 
read it via e-mail, mobile phone or a newsfeed viewer.

Study highlights data acquisition trends
   A recently completed study from Venture Development 
   Corporation (VDC) found a trend towards higher 
   resolution in A/D converters. Most shipments currently 
   have A/D converters with 12- or 16-bit resolution: VDC 
   forecasts this to change. Many purchasers seem to 
   equate resolution directly with accuracy  reasoning 
   that the better the resolution, the higher the accuracy. 
   Thus, if they can afford the higher resolution units, 
   they will purchase these. Declining prices for the 
   higher resolution products are helping this trend. 
   Another shift is to equipment with more input 
   channels. (Note: for an explanation of resolution 
   and accuracy see Monitor # 95.)
   Source: Venture Development Corporation

Synchronising 'heartbeat' saves sensor batteries
   "Pumping" data around a wireless network of sensors 
   - just as blood is pumped around the human 
   circulatory system - could allow the sensors' 
   batteries to last four times as long. Sensor networks 
   are usually "tree-like". Their branching structure 
   means information gets from A to B quickly, but 
   means devices have to be turned on permanently to 
   co-ordinate the data traffic. A new system that 
   synchronises the flow of information from node to 
   node around the network. Nodes only turn on when the 
   beat reaches them, saving battery power - but the 
   system is slow because data has to travel all the 
   way around the network.
   Source: New Scientist

Saving Energy in Buildings
   Adopting currently available technologies could 
   reduce annual CO2 emissions in London by nearly 
   44 percent. Almost 70 percent of the potential 
   abatement could be achieved with the help of 
   technologies that would pay for themselves, largely 
   by reducing energy costs, according to a study by 
   McKinsey.  The biggest saving potential lies in 
   buildings: measures such as building automation 
   systems and insulation could reduce London's 
   emissions by a third by 2025.
   Source: Siemens

Low energy X-rays inspect food
   New inspection X-ray technology developed by 
   European researchers is helping to ensure that 
   the only thing in people's dinners is the food 
   itself.  The technology uses low-energy X-rays to 
   produce highly detailed images of food products 
   and packaged goods. The images are then scanned 
   via inspection software that can automatically 
   detect any irregularities accurately and quickly. 
   The system can be used to check seals on food 
   wrappers, locate packaging defects and find foreign 
   particles of any size in any kind of food, from 
   maggots in apples to grains of sand in bread. 
   Source: ICT Results

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* Reprinting permitted with this notice included
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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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