Field device for determining or monitoring a physical or chemical process variable

Abstract

A field device for determining or monitoring a physical or chemical process variable, wherein the field device is composed of a sensor, which works according to a defined measuring principle, and a control / evaluation unit (10), which, as a function of a safety standard required for the particular safety-critical application, conditions and evaluates, along at least two equivalent measuring paths (MP1, MP2), measurement data delivered by the sensor. The control / evaluation unit is implemented on an FPGA (1), on which are provided at least a first section (3.1) and a second section (3.2), wherein, in each section (3.1, 3.2), a digital measuring path (MP1, MP2), which is composed of a plurality of software-based and / or hardware-based function modules, is dynamically reconfigurable. The sections are isolated from one another by permanently configured spacer regions (4.1, 4.2), wherein the spacer regions (4.1, 4.2) are embodied in such a way, that a temperature and / or a voltage change in one of the sections (MP1; MP2) has no influence on the other section (MP2; MP1) or other sections, and, in the case of malfunction, no connection occurs between the sections (MP1, MP2). The control / evaluation unit (10), as a function of the particular defined safety-critical application, partially dynamically reconfigures the function modules in the measuring paths (MP1, MP2) in such a manner, that the field device fulfills the required safety standard. Preferably a voter / microcontroller is used to compare measurement data in the measuring paths and is capable of reconfiguring the function modules and generating a warning of defective data.

Description

technical field [0001] The invention relates to a field device for determining or monitoring a physical or chemical process variable, which consists of a sensor which operates according to a specific measuring principle and a control / evaluation unit which is dependent on the corresponding The safety standard required in safety-critical applications processes and evaluates the measurement data provided by the sensors along at least two equivalent measurement paths. Preferably, the field device is used in automation technology, in particular in process automation and factory automation. A solution is known from WO 2004 / 013585 A1 which deals with the design of field devices which can be used in safety-critical applications in the field of process automation. However, the invention is not restricted to the field of process automation and factory automation, but can also be used in safety-critical applications in the automotive industry and other industries. Background technique...

AI Technical Summary

Problems solved by technology

[0013] The problem with the known construction is that functional faults, such as a short circuit or a temperature change in one partition, automatically also affect the other partitions

This leads to crosstalk to other partitions, so that field devices may provide erroneous measurement results and no longer work reliably

This is an unacceptably high risk, especially in safety-critical applications

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