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Data loggers and data recorders are instruments that receive and record DC voltage, DC current, AC voltage, AC current, frequency, and charge. More generically, data loggers record measurements (temperature, relative humidity, light intensity, on/off, open/closed, voltage, pressure and events) over time. Sensor inputs include accelerometer, thermocouple, thermistor, RTD, strain gauge or bridge, pressure sensor, current loop transmitters, and LVDT or RVDT.
Data loggers and data recorders are often used to store data for subsequent downloads to a PC, but may also offer real-time features such as monitors and alarms. Data loggers (which are not necessarily data recorders) are often small, battery-powered devices that are equipped with a microprocessor, data storage and sensor. Most data loggers utilize turn-key software on a personal computer to initiate the logger and view the collected data.
above: 10 Color, 20 Input Hybrid Benchtop Recorder from Omega Engineering.
Important specifications to consider when shopping for data loggers and data recorders include:
Other specifications to look for include:
A smart protocol standard called 'SDI-12' exists that allows some instrumentation to be connected to a variety of data loggers. SDI-12 also support multi drop instruments.
Types of User Interfaces:
Host Connection types:
Data loggers and recorders may also be Web enabled, allowing programmability via a web browser.
above: dataTaker DT80 -- a modern, stand-alone data logger/data-acquisition system
Data Loggers vs. pure Data Acquisition systems
A data logger is a data acquisition system, but a data acquisition system is not necessarily a data logger. This distinction has both pros and cons for data loggers.
Data loggers may be compact, portable and all-in-one units: Some data acquisition systems require the installation of a DAQ card in a PC. Wiring from sensors, transducers, thermocouples must also be brought over (and connected to) the PC. These systems work well in permanently-configured, on-line applications but may be expensive and difficult to implement otherwise. Data loggers significantly reduce the cost-per-channel for most logging applications and are significantly easier to implement. They can be placed in areas that bulky DAQ systems can not reach.
Data loggers typically have slower sample rates. E.g., a maximum sampling rate for a data logger may be 5 Hz -- this is considered very slow for full DAQ systems.
Updated: Tuesday, March 3, 2020 22:48 PST