Long-term Acquisition, Recording and Storage of Measurement Data
Data loggers are measurement systems that record measurement data at specific intervals over a longer period of time and store it on a storage medium. In other words, they are comparable to a classic chart/line recorder, which writes the continuous temperature or humidity profile directly onto a paper web as a line graph. Originally, the data was only recorded in order to evaluate it at some later point in time.
Of course, modern data loggers use digital and microprocessor technology. Thus, the original "data recorder" often becomes a complete and possibly multi-channel monitoring or even automation system. The devices then also take on monitoring tasks, for example: A reaction can be triggered when the measured value exceedes/falls below a defined limit - from an alarm to a switching operation, etc.
From a technical point of view, modern data loggers are usually classically designed data acquisition systems, i.e. they are essentially based on an A/D converter circuit. Thus, the actual recorded basic variable is often a voltage. Therefore and thanks to modern sensor technology, many different measured variables are conceivable for data loggers - temperature and relative humidity are obvious and widespread. But there are also variables such as acceleration, vibration/shock and many more - and of course voltage/current directly.
Application Areas of Data Loggers
- Building/room monitoring (incl. goods/food/pharma warehouses, stables in agriculture, museums, residential climate, IOT etc.).
- Transportation monitoring, transportation insurance.
- Environmental engineering, climate research.
- Enclosure internal temperature of equipment.
- Industrial process, machine and equipment monitoring, IIOT, predictive maintenance.
- Medical applications.
Basic Principles of Data Loggers
According to the applications and measured variables, the designs and functions of data loggers are very diverse:
- From completely autonomous (operation, display on the device, fully autonomous operation) to
semi-autonomous (autonomous operation after configuration via PC/mobile device; data transfer and display via PC/mobile device) to
PC-bound (operation with a permanently connected PC).
- Power supply via power supply adaptor or autonomous/mobile via battery/rechargeable battery.
- Fixed sensor (for example temperature and humidity) or flexible voltage connections for different sensors.
- Pure data recording or additional functions like alarm, control channels etc.
- Interfaces (wireless IrDA, WLAN, wired USB, Ethernet).
- Data storage: Internal, expandable (SD card), to PC memory, to Cloud etc.