Type ISM: The wireless data transmission takes place in the 2.4 GHz ISM band. Built-in Li-Ion or LiFePo4 batteries take over the power supply. In practice, depending on the sensor type, measurement regime, hit rate, ambient temperature and aging of the Li cells, operating times between 24 and 240 hours can be achieved without recharging. In the worst case, the power consumption of a sensor is 91 mW. An obvious benefit is that no cables are required.
Type SPE: Data transmission and power supply take place via Single Pair Ethernet (SPE). Aufgrund ihrer geringen Durchmesser und hohen Flexibilität lassen sich SPE-Kabel leicht verlegen. Cable lengths of up to 1400 m m are possible for point-to-point connections. Multidrop bus lines and / or mid-devices reduce the total cable lengths by up to 10 % compared to conventional central AE systems. When using a mid device, each cable is shorter than the sensor distance. Multidrop bus lines lead to cable lengths that correspond to the transducer spacing. The maximum power consumption of a sensor is less than 105 mW. The SPE solution is independent of interference in the widely used ISM band.
Type DUAL: The dual sensors have both an ISM antenna and SPE connector. They can be used as ISM or SPE sensors and combine the advantages of both types. Disadvantages are the larger construction volume and the shorter operating times.