Data logging is the technique used to measure and record the physical parameters over a period of time. This method is used in various applications like environmental monitoring, health monitoring, machinery monitoring, vehicle data logging etc. Common measurements in Data logging include measurement of temperature, pressure, voltage, strain, force, acceleration, current etc. Data logger is a paperless chart recorder that measures the physical parameters and converts them in to digital data. Data logger has built in display or facility to transfer the data into the PC. The data can be stored for long time and it is easy to generate the report at any time. Data loggers are more easy to use than the Real Time Data Acquisition Systems and Chart Recorders.
The earliest form of data recording was taking measurements of the physical parameters through manual measurements and writing the same in a log book and then making a graph manually in graph paper.
Later this process was automated and the data was recorded on Strip Chart Recorders to generate the chart of the measured data. With the introduction of computer based data recordings, the task is now very easy. The advantages of the data logging includes user defined functionality, Real time visualization, Huge data storage, Inline analysis, Network connectivity etc. Data loggers are available in different forms from simple single channel fixed function logger to programmable loggers with multi functions. Tiny tag data loggers are available to monitor temperature, humidity and other environmental parameters. Wireless data loggers are also available.
Advantages of Data logger
Data loggers are economical than the chart recorders and are highly flexible and user friendly.
- Data can be stored in non volatile memory that can be transferred to the PC.
- PC is not required during the data collection stage.
- Data storage can be 1 or 2 samples per second or maximum 100 samples per second.
- Most loggers are battery powered using long life Lithium polymer battery. The battery can last for more than 10 years.
- The data stored in the non volatile memory of the data logger so that even if the battery fails, the data will be safe.
Duration of the data recording depends on the capacity of the logger and the number of sampling.
Temperature Data Logger
Uses of Data logger
- Unattended weather station recording to collect weather data such as wind speed, humidity, temperature, sunlight intensity etc.
- Hydrographic recording such as water level and depth, water conductivity, pH etc.
- Soil moisture determination.
- Road traffic counting.
- Vibration and shock resistance in machinery.
- Vehicle testing including impact of vehicle crash.
- Environmental monitoring.
How it works?
The logger is placed in the device or places where the signals are to be collected. The Sensors of the logger act as the input for the signal. The signal acquisition is the initial process of data logging. The received signals over time will be stored in the non volatile memory and can be visualized through the LCD screen or can be transferred to PC for further analysis and charting.
In PC based data logger, the data is first recorded and then manually transferred into PC before importing into the spread sheet to visualize the data. Using the software like Ni LabVIEW it is easy to create the programming environment to build the user interface.
Using the capacity of the PC RAM, it is easy to analyze and interpret the data acquired by the logger. Many mathematical or statistical programmes can be used for the inline analysis. PC based loggers are software defined devices so that the functionality of the device can be controlled by the software. It is easy to customerize the software according to the application needs. Logging conditions, generation of report, signal analysis, custom alarm etc can be customerized easily. The data can be imported into other tools to share the data or for uploading.
Data logger can store large quality of data that can be used for PC analysis. The PC having Terabyte storage can handle very large amount of data acquired by the logger.
Unattended instruments can be monitored using the data logger. Network connectivity of the data logger helps to monitor or analyze the data from a remote place.
- Low cost temperature data logger using PIC and Processing (electronics-lab.com)