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The Past and Present of Data Logging

Grant enews picAfter three decades, the data logging market is still going strong driven by new technologies, greater penetration of wireless data links and Web enabled instrumentation, says Nathan Neal of Grant Instruments.

According to the 2011 research report titled 'Data Acquisition (DAQ) Hardware: A Global Strategic Business Report' from Global Industry Analysts, Inc., the data logging market is forecast to exceed US$1.3 billion in 2017.

Despite being around for 30 years, data loggers continue to evolve owing to regular introduction of new technologies and are now a most vital constituent of the measurement market and indispensable in the research and development field for collection of physical measurement data.
So what is a data logger? A data logger is an electronic device used to measure and record physical or electrical parameters such as temperature, strain, displacement, flow, pressure, voltage, current, resistance, and power over a period of time.

This data is usually measured via internal or external sensors. Modern data loggers, driven by latest microprocessor technology, are capable of acquiring, processing, storing and analysing data at high speeds and are commonly used in a wide range of scientific experiments, engineering research projects and monitoring systems.

The first form of data logging through chart recorders was introduced in 1961, with Grant Instruments pioneering the design and manufacture of such products to monitor temperature. Paperless recording of data was soon to follow, firstly onto a cassette tape and later onto a solid state memory recorder. These recorders also had additional capabilities to record more physical parameters such as humidity, temperature (for example monitoring beer and soft drinks pasteurisation) and the higher temperatures of metal parts as they passed through paint stoving ovens.

By the mid-1980s, Grant introduced the very first truly portable microprocessor controlled data logger, the Squirrel data logger, with a built in liquid crystal display.
Microprocessor technology

The modern data logger is typically quite a small hand-held device with a large memory. They are powered by the latest microprocessor technology and capable of acquiring, processing, storing and analysing electrical signals at high speed (up to GHz) from a wide range of sensors - at regular intervals or in response to an event such as a threshold being crossed or a switch being activated.

The sensors may communicate with the logger through a cable or wireless link and may sense temperature, humidity, pressure, flow, wind speed, current, voltage, resistance and a host of other physical parameters that are important in monitoring and controlling processes or conducting research.
For example, Grant's SQ2040 logger features twin microprocessors, four 24-bit analogue-to-digital converters, 16 true differential or 32 single end channels, 8 event inputs, plus USB and RS232 connectivity. It can store up to 14 million readings in the onboard memory and is powered from internal cells, an external power supply or via USB connection.

Data stored by stand-alone data loggers is typically downloaded into a computer for more detailed analysis and reporting, though some data loggers have sophisticated on-board processing and analysis capability and can carry out some control functions such as activating an alarm or a switch to start or stop an ancillary piece of equipment.

The advantage of using a dedicated portable data logger compared to, say, a PC, is that the logger hardware and software are specifically designed for stand-alone data logging applications. This means that it is easy to connect and set up sensors and the logging system is more rugged and less power hungry, making it capable of running on batteries for longer periods of time, often in hostile environments.

Wireless data links The advent of wireless communication and networking means that it is possible to both install and interrogate a logger remotely which can be extremely useful for unattended or remote applications. These wireless communications devices can also be hugely beneficial by being relatively simple to install when deploying site wide monitoring systems across a large facility or shop floor.

Web-enabled loggers and instrumentation are expected to dominate the DAQ market in the near future, according to the Global Industry Analysts report, and make it possible to cost-effectively manage data from multiple, geographically remote locations via a standard browser interface. This is particularly useful for environmental monitoring projects as well as for field research and field engineering, where different stakeholders require remote and speedy access to the very latest data.
Diverse applications

Data loggers can be used in a wide spectrum of different applications in a broad range of industries. Data loggers can be used for monitoring different crops inside and outside of glasshouses by logging such parameters as air, soil or leaf temperatures as well humidity, CO2 and solar radiation.
Other uses can be monitoring solar heating systems, internal and external temperatures, process parameters, water temperature and flow together with electrical consumption. Other slightly more exotic applications include logging temperature of chocolate bars passing through cooling tunnels as well as internal body and skin temperature of sportsmen in endurance or extreme environment training.

Industries where data logging is commonly used include earth & life sciences, agriculture, food and water production and quality, energy production and conservation, medicine & pharmaceuticals, chemistry & chemical, work & sport activities, engineering, aviation, transport, building industry, meteorology, zoology and conservation.
Grant Instruments
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