Field device electronics fed by an external electrical energy supply

Abstract

The invention relates to an electronic system for a field device comprising a current controller, through which a supply current flows, for setting and / or modulating the supply current, the latter being driven by an supply voltage that is provided by means of the external energy supply. The electronic system for a field device also comprises an internal operating and evaluation circuit for controlling the field device, in addition to an internal supply circuit that is applied to an internal input voltage of the field device electronic system, is separate from the supply voltage and feeds the internal operating and evaluation circuit. A useful voltage controller, through which a first partial current of the supply current flows at least intermittently, is provided in the supply circuit, said controller providing an essentially constantly controlled first internal useful voltage at a predeterminable first voltage level in the electronic system of the field device. In addition, the supply current comprises a second useful voltage controller, through which a second partial current of the supply current flows at least intermittently, said controller providing a second internal useful voltage in the electronic system of the field device that can be varied within a prededeterminable voltage range and a voltage controller, through which a third partial current of the supply current flows at least intermittently, for setting and maintaining the internal input voltage of the field device electronic system at a predeterminable voltage level. According to the invention, both a first useful current that is driven by the first useful voltage and a second useful current that is driven by the second useful voltage flow through the operating and evaluation circuit at least intermittently.

Description

technical field [0001] The invention relates to a field device electronics for a field device which is powered by an external power supply, and to a field device having such a field device electronics. Background technique [0002] In industrial process measurement and automation technology, especially in connection with chemical automation or technical process process and / or industrial plant control, for the local generation of measured value signals analogously or digitally representing process variables, measuring devices installed in the vicinity of the process are used, i.e. So-called field devices. Likewise, a field device can be implemented as a regulating device for changing one or more of these process variables and effectively directing the flow of the process. Such process variables to be detected or regulated include, for example, the mass flow rate, density, viscosity, fill level, limit level, pressure of liquid, powder, vapor or gaseous media conducted or stor...

AI Technical Summary

Problems solved by technology

However, a disadvantage of such field device electronics is that all internal consumers are supplied essentially from the same internal effective voltage, and a possible collapse of this single effective voltage (for example, due to too low a supply current) can cause the field device No longer able to operate normally, or even cause a sudden and temporary total shutdown of the field device electronics

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