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The components required for data loggers

[2013-04-09]

    A data logger is an electronic device that records data over time or in relation to location either with a built in instrument or sensor or via external instruments and sensors. Increasingly, but not entirely, they are based on a digital processor (or computer). They generally are small, battery powered, portable, and equipped with a microprocessor, internal memory for data storage, and sensors. Some data loggers interface with a personal computer and utilize software to activate the data logger and view and analyze the collected data, while others have a local interface device (keypad, LCD) and can be used as a stand-alone device.      
The main components for data loggers as below:
    First, hardware: Hardware which includes the sensors, signal conditioning hardware and analog to digital conversion hardware.
Second, sensor: A sensor is a device which converts one form of energy into another form. Usually, the sensors convert the physical quantities into corresponding electrical signals. The input to the data logger is taken from sensors. These electrical signals, received from sensors, are analog signals and must be converted into digital signals using the analog to digital converter. The digital signal is sampled at a particular rate, where the term sampling rate implies the number of times the signal is measured. The sampling rate must always be greater than the frequency of the original signal. This sampled signal is fed to the computer via a serial port.
   Third, a serial port: The data logger is connected to the computer via a serial port. The electrical signals are used by the data logging software that analyzes the signals and stores them. The software used for data logging helps us to configure the time for which the sensors must sense the physical quantities. The data logging software also has an alarm system and a provision to set the sampling rate of the device. The procedure of using a data logger is as follows:
    Forth, the data logging software: The data logging software is configured according to the input sensor selected.
In addition, the parameters like the starting and stopping time and alarms along with other settings are configured using the data logging software. Data logging task is started and then the logged data is analyzed and stored using the software.