What is Data Acquisition?
Data Acquisition is simply the gathering of information about a system or process. It is a core tool to the understanding, control and management of such systems or processes. Parameter information such as temperature, pressure or flow is gathered by sensors that convert the information into electrical signals. Sometimes only one sensor is needed, such as when recording local rainfall. Sometimes hundreds or even thousands of sensors are needed, such as when monitoring a complex industrial process. The signals from the sensors are transferred by wire, optical fibre or wireless link to an instrument which conditions, amplifies, measures, scales, processes, displays and stores the sensor signals. This is the Data Acquisition instrument.
In the past Data Acquisition equipment was largely mechanical, using smoked drums or chart recorders. Later, electrically powered chart recorders and magnetic tape recorders were used. Today, powerful microprocessors and computers perform Data Acquisition faster, more accurately, more flexibly, with more sensors, more complex data processing, and elaborate presentation of the final information.
What is a Data Logger?
A data logger is an electronic instrument which connects to real world devices for the purpose of collecting information. Data logger can be pictured as a black box recorder in aeroplanes. These data loggers record mainly voice and the plane stats data information.
Real world Devices could include the following:
- • Temperature sensors
- • Pressure sensors & strain gauges
- • Flow and speed sensors
- • Current loop transmitters
- • Weather & hydrological sensors
- • Laboratory analytical instruments
- • And much more...
Why Collect Information?
To look back on past events and identify areas of interest and most of all saving cost and time. These events could assist in improving the following:
- • Efficiency
- • Performance
- • Accuracy
- • Reliability
- • Energy consumption
- • Quality Assurance
- • etc.
Real Time Data Acquisition and Data Logging
Data Acquisition can be divided into two broad classifications – real time data acquisition and data logging. Real time data acquisition is when data acquired from sensors is used either immediately or within a short period of time, such as when controlling a process. Data logging on the other hand is when data acquired from sensors is stored for later use. In reality, there is a continuum of devices between real time data acquisition and data logging that share the attributes of both of these classifications.
Stand-Alone or PC based?
Dedicated data loggers have many inherent advantages over PC based alternatives for the bulk of data acquisition tasks. These include low power operation, standby power sources and security of data in the event of power or communications failure. Being specifically designed for the task, errors due to influences such as poor noise immunity and unstable operating systems are minimised. A dedicated data logger supporting anything from thermocouples to strain gauge sensors, will process and return data to a PC in real time.
Evolution in Data Acquisition
Data Acquisition technology continues to evolve, with high speed data interfaces and networking forcing major change to previous practices. Sensitive low level signals can now be left in the field, with just the desired data being returned to a remote computer for analysis. This is the function of a dataTaker data logger or DAQ box, providing the functionality and speed of a DAQ board, adding the standalone capability to process, consolidate and log data for later downloading. A series of data loggers interconnected by a network allows data gathering closer to sensors, for improved signal quality and reduced installation cost.
A Simple Decision
So why choose data logger over other data acquisition systems? Most data acquisition systems require installation of a DA card in a PC and the connection and wiring of the sensors. These systems work well in permanenty configured, on-line applications but is difficult to implement and can be costly. Data loggers significantly reduce the cost for most logging applications and are much easier to implement, and can be place in areas that digital systems can not reach. The simple alternative, dataTaker data loggers stand alone solid state data loggers that operate anywhere, independent of your computer. they store data in the format you choose, compatible with your computer and your software systems. dataTaker data loggers are flexible and any one of our data loggers can easily be configured to gather data in almost any environment you choose. There are dataTakers in rain forests, down mines and in the upper atmosphere. In cars, in boats and planes. on farms, in factories and laboratories. dataTaker is truly universal.
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