Data logger
A data logger is a microprocessor-controlled storage unit, which receives the data in a certain rhythm via an interface and stores it on a storage medium. This can be done by software, if the present data to be logged, for example, information within a computer already in digital form and only need to be treated. If the information is, however, only in non- electrical form available, the data logger from a special combined with hardware sensors can be made, the physical measurement data recorded over a certain period of time, such as temperatures, voltages, and accelerations.
Construction
A data logger consisting of a programmable microprocessor, a storage medium, at least one interface and one or a plurality of channels for connecting the data source, such as sensors. The data acquisition is performed externally or internally via a vendor specific interface. An internal interface is available if the data logger is a temperature sensor with a sensor such as a single unit. The data are transmitted from the sensor directly via the internal interface to the data logger and stored. Each data logger has at least one external interface for receiving and delivering data from or to the environment. In the industrial and mechanized environment, RS232, CAN and USB are the most common interfaces.
About ports such as USB, D -Sub, Bluetooth, Wi-Fi or industrial clamps any external devices, sensors or machines can be connected as a data supplier. About this accesses a data logger is usually configured for its use (eg, start and end time of the measurement, measurement interval, etc.). The data type is not initially specified in more detail. Depending on the application it may be process or sensor data. Memory rhythm depends on the specific use. The storage process can be carried out in precise intervals or each at the moment of data generation. In any case, the save operation is always performed fully automatically.
Sensor - logger
For specific applications in sensor data logger and sensor are installed in a device. Over the sensor, the corresponding measurement data, such as temperature, air pressure, etc. are recorded. By an analog -to-digital converter, this data is then converted data into "memory -oriented " and saved on the storage medium. By way of storing a data loss can be prevented ( with empty battery ). The collected data is read via the interfaces ( serial, USB, LAN, Bluetooth, etc.) and analyzed with appropriate software. Depending on the desired measurement variables can have one or more channels of a data logger to simultaneously connect multiple sensors.
Disposable logger
For control of shipments of disposable data loggers are designed to provide a cost effective solution for single-use applications. The lifetime of these devices is usually limited to 1 year, before all advisable where a return of the equipment would be too expensive ( export shipments ). This temperature loggers have a USB interface and thus come out with no additional hardware. Thanks to the PDF analysis (see below) is also required no special software.
PDF Logger
A special variant of autonomous data logger is the PDF Logger. This created automatically when plugged into a USB port, a PDF file with a text and a graphic of the current measurement data. The PC operating system, the device shows up then as a standard USB mass storage. This makes it possible for the recipient worldwide to generate a report without additional software. These devices are used for the shipment in the cold chain.
Mini - logger
Mini data logger, often called USB Logger, have a small format. They are available either with internal or external sensors to record various indicators, but have, despite their small size, a high storage capacity. Be used Mini-Logger everywhere in industry and science, where the size is an important consideration: for example, in health care when Patientenmonitioring, in which the patient must take the data logger for long periods. In research mini- loggers are used, for example, to measure acceleration forces on the human body (eg, pilots, parachutists, etc.). In business, there may be about to operate unobtrusively with the small logger transport monitoring.
In museums or galleries, in turn, mini- loggers are necessary for climate monitoring. To gain meaningful readings from the immediate vicinity climate of the object, the logger must be placed very close. However, museum visitors as possible should not see the logger, which speaks for the Mini-Logger. The measurements of the Mini-Logger can be transferred to a PC during both measurements as well as after graduation via USB.
Underwater data logger
Underwater data logger are not only of waterproof housing a larger memory for measured values and are more power efficient constructed. This allows them to be hard to reach areas in use and also collect data for months. After replacing the memory, the data as normal data loggers can be easily read by the interface. Waterproof data logger are not only used in the aquatic environment. They are used, for example, in manufacturing processes. Here, the data logger comes with the product in the packaging and checked whether the production important variables such as the pressure or temperature are observed.
Demarcation to the vehicle diagnostic system
The term data logger is often confused, especially in the automotive industry with the concept vehicle diagnostic system. This offer data logger normally mainly functionality to record measured values and other data. Vehicle diagnostic systems go beyond that and master data reduction, processing and visualization of data as well as other functionalities that assist the user in the analysis.
Specifications
One must distinguish between loggers for "home use " and loggers for professional use. The latter include, inter alia, the following properties:
- A calibration certificate, traceable to an accredited calibration
- Have a much higher robustness
- Have " Excite " outputs to connect active ( strombenötigende ) sensors can
- Have programmable inputs
- Have wide input voltage ranges
- Have their own precise clock
- Extended temperature resistance
- Have one or more alarm outputs
- Have extensive possibilities to trigger (eg event-controlled start of recording )
- Have opportunities for networking and remote control
- It is if necessary. the possibility for remote access
- Have a high accuracy and long term stability and high storage capacity
- The inputs / outputs are standardized
- Have the ability to connect any ( non-proprietary ) Sensors
- Have a battery / battery to bridge power failures.
Heartbeat
For particularly critical applications, the data logger can be equipped with a heartbeat signal generator so that the surveillance personnel about a possible failure is promptly informed. This can be, eg, an SMS is sent via mobile.
Swell
Avisaro - Glossary Data Logger