Arrangement for signal transmission in a measuring arrangement

Abstract

Abstract The arrangement serves for signal transmission in a measurement circuit containing a measurement transmitter and an evaluation unit located at a distance therefrom. The measurement transmitter is connected to the evaluation unit by a twin-conductor lead (11) via which on the one hand the d.c. current power needed for operation of the measurement transmitter is conveyed to the measurement transmitter and via which on the other hand the measurement value signals which represent the measurement values are conveyed to the evaluation unit. The measurement transmitter is connected to the twin-conductor lead via a measurement transmitter interface (16) which takes the d.c. current power needed by the measurement transmitter from the twin-conductor lead and applies the measurement value signal to the twin-conductor lead. The evaluation unit is linked with the twin-conductor lead via an evaluation interface (18) which is designed to apply the d.c. supply voltage to the twin-conductor lead and to receive the measurement value signal transmitted over the twin-conductor lead. In addition, at least one communication unit is provided which if needed can be connected via the communication interface (40), parallel to the measurement transmitter, to the twin-conductor lead. In the measurement transmitter interface, the evaluation interface and in each communication interface a corresponding communication interface circuit is provided which contains a signal generator (41, 51, 61) and a signal receiver (42, 52, 62). The signal generator of each communication interface circuit is so designed that it reduces the d.c. supply voltage, in terms of pulse shape, on the twin-conductor lead in accordance with a pulse modulation which represents the communication signal. The signal receiver of each communication interface circuit responds to the voltage modifications in terms of pulse shape on the twin-conductor lead. In this way, all of the devices connected to the twin-conductor lead can exchange information without the transmission of the measurement value signals over the same twin-conductor lead being impaired.

Inventors

• 👤 Gustav Wetzel

Bibliographic Details