Two-wire field device for process automation technology for connecting at least one sensor element

Abstract

A two-wire field device for process automation technology for connecting at least one sensor element comprises a first supply part V1, which can be connected to a field bus FB via a first two-wire connection A1. The field device FB is completely supplied with energy via the field bus. The two-wire field device comprises a second supply part V2, which is connected to the first supply part V1 and serves the energy supply of a sensor bus SB via a second two-wire connection A2. Furthermore, a field bus communication unit FKE, which is connected to the first two-wire connection A1 and the first supply part V1 and which serves the data exchange via the field bus, and a sensor bus communication unit SKE, which is connected to the second two-wire connection A2 and the second supply part V2 and which serves the data exchange via the sensor bus, are provided. A processing module VM is connected to the field bus communication unit FKS, the sensor bus communication unit SKE, and the first supply part V1. According to the invention, the field bus FB and the sensor bus SB are galvanically isolated from one another.

Description

technical field [0001] The invention relates to a process automation two-wire field device for connecting at least one sensor element as defined in the preamble of claim 1 . Background technique [0002] A 2-wire field device of this type for process automation technology is known from US 6,574,515 to which a plurality of sensor elements can be connected and which is energized via a 2-wire process control loop. The measured values ​​sent from the sensor elements are processed in the processing module and passed on to the superordinated unit via a communication interface connected to the two-wire process control loop. [0003] In the case of such two-wire field devices, a plurality of sensor elements are combined into sensor groups and each group is connected to a processing module via a multiplexer. The data transmission between the multiplexer and the processing module takes place digitally. In order to galvanically isolate the sensor element from the processing module, a...

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Problems solved by technology

[0004] A disadvantage of this arrangement is the need for galvanic isolation in the communication lines and in the voltage source lines for each sensor group

[0005] Another disadvantage of this arrangement is that four wires have to be routed to each sensor element, which requires considerable wiring expenditure

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