Telemetry stands for remote measurement technology. As a rule, measured values are transmitted wirelessly from remote sources to telemetry centers via radio LANs or mobile radio networks. Telemetry basically uses the same measurement techniques as are common in the laboratory. Here, physical variables such as temperature or pressure are recorded by high-precision sensors, converted into electronic measured values, transmitted, collected and evaluated.
In telemetry, the physical variables recorded by a sensor are digitized and, after digitization, transmitted by radio to a receiving station or the telemetry center using the familiar multiplexing and modulation methods. The telemetry systems use PCM technology for this purpose. Depending on the distance between the sensor or telemetry transmitter and the control station, the measured value transmissioncan be near field communication( NFC) or remote telemetry using the known radio LANs and mobile radio networks suitable for data transmission.
Starting from WLANs via Bluetooth to the well-known mobile radio networks General Packet Radio Service( GPRS), High Speed Circuit Switched Data( HSCSD), Enhanced Data Service for GSM Evolution( EDGE) or UMTS.
There are several proprietary and IEC standardized telemetry protocols for the transmission of telemetry data. The former include Siemens' ModbusRTU and Sinaut, and the latter include IEC 61850, IEC 60870-5-101 and IEC 60870-5-103.
The application areas of telemetry have evolved from high-tech aerospace applications to general industrial, medical and environmental applications in the Internet of Things( IoT).