Tips & Tricks

Yes, a transmitter repeater or transmitter repetition amplifier can supply the 2 or 3-wire transmitter with energy by galvanically isolated means.

A 2-wire measuring transducer takes its voltage supply from the measuring signal, the current for which is provided by the transmitter repeater. In the case of 3-wire measuring transducers an additional input terminal with feeding voltage is available to the transmitter.

Hart Communication is a standardized method of additionally transferring bi-directional communication on an analog measuring value. The modulation and the data log are defined exactly in the specifications of the HART Communication Foundation (www.fieldcommgroup.org/technologies/hart).

This is an FSK signal which is modulated in the measuring transducer to the measuring value, 4 - 20 mA output current of the transmitter. A HART modem is installed in the process controller; it transports the transmitted digital data to a process computer.

The great advantage of this concept is that the analog measured value can be evaluated conventionally. Furthermore, but without any additional cabling work, all kinds of information such as measured values, configuration data or set parameters can be made available to the user in digital form.

Our transmitter repeaters supply the feeder voltage for your transmitter.

2-wire transmitters regulate their own power consumption proportionate to the measured value; here the 4 - 20 mA connection provides the auxiliary energy for the transmitter and the level of the current is at the same time the output measured value.

3-wire transmitters usually have an active current output for the measured value and additionally terminals for the supply voltage (auxiliary energy).