What Is a Data Logger?
Data Loggers are devices that store various types of data measured and collected by sensors.
They record at a rate of 10 to 1,000 times per second (10 to 1,000 Hz) at the fastest, and are intended for use in devices that observe signals at a slightly slower rate. The advantage is that it can operate and record independently of a computer.
They range from single-channel loggers to loggers capable of handling hundreds of inputs, depending on the application. There are two types of data loggers: those that record on paper and those that store digitally or analogously in memory.
Uses for Data Loggers
Data loggers can record data on most physical phenomena, including temperature, humidity, vibration, sound, speed, acceleration, and electrical quantities. Since multiple data can be recorded simultaneously, data loggers are used to investigate correlations between data. For example, data on indoor temperature, humidity, and wind velocity.
1. Indoor Temperature Distribution
Since data loggers can record hundreds of multi-channel data, they can be used to evaluate indoor temperature distribution, air velocity distribution, and temperature and humidity drop rates due to air conditioning.
2. Clutch Durability
They can be used to record pressure, stress, and temperature applied to automobile clutches to conduct durability evaluation tests.
3. Logistics Testing of Precision Equipment
To evaluate damage or functional failure of precision equipment due to vibration during transportation, data loggers are used to conduct actual transportation tests and tests on a vibration table.
Principle of Data Loggers
Data loggers that record on paper are equipped with a mechanism called a pen servo that moves the pen to a position proportional to the input signal. The pen servo can also print information such as channel number, tag name, and recording time in the margin of the recording paper.
Paperless data loggers store temperature and other data in internal memory. The data is then downloaded to an external computer for analysis. Newer models can also analyze the stored data on the main unit.
The format of the recording depends on the model, but a dedicated application facilitates visualization and analysis. Data loggers can record data not only on a daily basis, but also for longer periods of time, such as a week or a month, due to the low sample rate of data loggers.
Features of Data Loggers
1. Easy to Set Up and Operate
Compact and lightweight design facilitates easy setup and operation, making measurement easy. Easy on-site measurement by utilizing a battery unit or wireless LAN.
2. Different Types of Data Synchronization
Mixed types of data such as voltage, temperature, strain, acceleration, and pulse can be stored and analyzed in perfect synchronization.
3. Easy Data Analysis
PC software is available for easy analysis.
Other Information on Data Loggers
1. Paper-Type Analog Data Loggers
While most data loggers are now digitalized, paper-type analog data loggers are rare. There are models with a recording width of 100 mm that have been popular for many years: traditional strike-through models with 2 to 6 channel inputs and pen-style models with 1 to 3 inputs.
Although the input type and scale are fixed specifications, there are few setting items, making it easy for anyone to use. The temperature scale is linear and easy to read, while the thermocouple and resistance thermometer inputs are analog. Combination of different types of inputs such as thermocouples and resistance thermometers is also possible.
The panel is embedded for easy installation, and the total weight of the unit is approximately 1.6 kg, making it easy to carry around.
2. Paperless Data Logger
Recent data loggers have become paperless, with many of them lacking an operation panel on the main unit. These paperless data loggers perform setting, operation, record retrieval, processing, display, and record storage through PC software, highlighting the growing importance of this software.
In addition, data loggers that can display measurement results on a screen have functions that allow easy display and retrieval of recorded data using only the main unit. Currently, a wide variety of products have been developed, including multi-channel products with color image displays and those that use a PC to display measurement results.