HART-Communication Two-wire transmitter for mounting in sensor-heads, field-housings or control panels.
Transmitters convert the low-level signal from thermocouple or resistance thermometer into a high-level standard signal. The non-linear input from temerature sensors is converted into a temperature or EMF - linear output signal, depending on programming, of 4 ... 20mA. The transmitter uses the HART - protocol and frequency shift keying on the 4 - 20 mA current output loop.
This system ensures either a multi - drop communication with up to 15 units or full operation as a - wire transmitter in a 4 - 20 mA current loop. The microcomputer-controlled system reduce type and range variety, usual with analog transmitters, to only one model. Significant lowered inventory costs, universal use, short change - over and shut - down times are the advantages.
For maximum operational safety and reliability in harsh ambient conditions like vibrations no mechanical components (potentiometers) are involved whereever possible. Extensive calculations like drift/offset compensation, linearisation limit comparision are done ''on site'' which means immediately close to the sensor. For the transmitter configuration a HART - interface as well as f.e. the measuring value, limits, cool joint temperature and so on without affecting the analog output of 4 to 20 mA.