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30 July 2012

Windmill Software Ltd
Data Acquisition Intelligence

The Newsletter for PC-Based Data Acquisition and Control
Issue 168           July 2012
--------------------ISSN 1472-0221----------------------

Today we are delighted to launch the 851-pH Data Logger 
which monitors up to 16 pH probes, controls digital 
outputs, counts and can measure other parameters like 
temperature and pressure alongside pH.

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Monitor Newsletter

* Windmill News: pH Data Logger is Built for Accuracy 
  and Reliability
* DAQ News Round-up

New pH Data Logger is Built for Accuracy and Reliability

851-pH Data LoggerWe are pleased to launch the 
851-pH Data Logger, which 
continuously monitors readings 
from 12 or more pH probes. 
It is available on-line from

The pH Data Logger:

- communicates with a PC over Ethernet or Internet

- includes the powerful yet easy-to-use Windmill 
  software: no programming required
- with automatic ranging lets the software match the 
  pH signal as closely as possible
- employs an integrating analogue-to-digital converter 
  to reduce electrical noise errors
- lets you choose the resolution of the A-D converter 
  from 12- to 18-bits for optimum accuracy
- provides automatic recalibration

- lets you set two alarms on each pH probe

- also offer digital inputs and outputs, and event and 
  frequency counting
- comes with free technical support for life and a 
  money-back guarantee

pH Measurement
The 851-pH package comprises an 851 Data Logger and a 
pH connection box.  Just connect your pH probes to the 
pH box's input protected sockets, plug the box into the 
851 Data Logger and away you go. This method of 
connection means you can use the 851 Data Logger to 
monitor, for example, temperature, flow or level at 
the same time as pH.

The standard pH package handles 12 pH electrodes, 
but can be expanded to 16 electrodes on request. 

Designed for Accuracy
The voltage produced by a change in pH is very small. 
A change of one pH unit on the pH scale produces 
(ideally) a change in voltage of 59.16 mV at 
25 degrees C. With the 851-pH package you can choose 
a narrow input range such as +/- 10 or 100 mV, or
select autoranging to let the software automatically 
choose the best range for your measurements. Choosing 
the smallest range that encompasses your signals will 
optimise the resolution of the measurement. 

You can also choose the resolution of the analogue-to-
digital converter, selecting 18-bit for more accurate 
measurements. The higher resolution slows down the 
system to 6 samples per second, but as pH changes 
relatively slowly this is not generally a problem. 
If you need faster measurements, choose 16- or 
15-bit resolution.

An integrating analogue-to-digital converter reduces 
internal noise and a differential amplifier helps 
reduce external noise.

To further improve accuracy, make sure you keep the 
wires between the electrodes and the pH box short - 
spanning not more than a few meters.

Set Alarms on Each pH Probe
You can set two alarm levels on each pH probe, and 
specify what happens when each alarm threshold is 
crossed. For example, an buzzer could be sounded or 
other equipment switched on.

Data Acquisition Software
Windmill Software is included in the 851-pH package. 
Our modular suite offers data logging, charting, 
alarm indication, output control and real-time links 
to other applications like Excel. You can also add 
process mimic generators, sequence control and many 
other modules. Should you wish to program the hardware 
yourself, you can use the IML Tools to do so.

Alternatively you can use the 851 as a stand-alone 
Data Logger, saving 65000 scans of all connected 
pH probes to memory.

Further Reading
More information on the 851-pH data logger,

How to measure pH with a computer,; accessed 30 July 2012.

Monitor Issue 93: The origins of the term pH


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 follow us on Twitter at!/DataAcquisition
or grab our RSS newsfeed at

Seabed sonar measures marine energy effect on wildlife
   Scientists are measuring what effect tidal turbines 
   have on wildlife. They have combined two sonar systems 
   on a seabed frame.  These have been adapted to operate 
   autonomously in combination for several weeks, while 
   facing upwards. Collecting the data in this way allows 
   imaging of a full 'acoustic curtain' along the tidal 
   flow and around the turbine in a highly challenging 
   Source: SCUBA News
NIST Measurement Advance Could Speed Innovation in Solar Devices
   A new versatile measurement system devised by 
   researchers at the National Institute of Standards and 
   Technology accurately and quickly measures the 
   electric power output of solar energy devices, 
   useful for developing the next-generation of 
   solar energy cells.
   Source: NIST
Motion detection technology identifies lameness in horses
   A motion detection system outperforms vets when 
   assessing horses for symptoms of lameness.  Sensors  
   are placed on the horse's head, right front 
   limb and near the tail.
   Source: University of Missouri

Market for Photoelectric Sensors Faces Increasing Demand 
   The market for photoelectric sensors experienced a 
   collapse and a dramatic rebound in the last 
   three years. The demand for sensing is increasing 
   with overall demand for sensors rising faster than 
   for industrial automation in general.
   Source: ARC Advisory Group

Dolphin research could lead to man-made sea mine detectors
   Research into the way dolphins use sonar could lead 
   to new man-made systems for detecting sea mines in 
   difficult conditions.
   Source: The Engineer

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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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