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

摘要

A field device for determining and/or monitoring a physical or chemical, process variable in automation technology. The field device comprises: at least one microcontroller; a supply unit of limited capacity as primary voltage supply; and a detection circuit, which signals the microcontroller of a failure of the supply unit so early by means of a detection signal that sufficient time is available to take suitable safety measures, in order to avoid loss of data. The detection circuit is so embodied that a reference voltage required for detection of a voltage decline of the supply unit has an almost constant offset from the supply voltage of the supply unit and adjusts to the supply voltage, until the detection circuit, in the case of an abrupt subceeding of the reference voltage, or an abrupt voltage decline of the supply voltage, sends a detection signal to the microcontroller.

主权项

1. A field device for determining and/or monitoring a physical or chemical, process variable in automation technology, comprising:
at least one microcontroller; a supply unit of limited capacity as a primary voltage supply providing a supply voltage; and a detection circuit, which signals said at least one microcontroller of a failure of said supply-unit so early by means of a detection signal that sufficient time is available to take suitable safety measures, in order to avoid loss of data, wherein: said detection circuit is so embodied that a reference voltage which serves as a switching threshold required for detection of a voltage decline of said supply unit exhibits a predetermined offset from said supply voltage and in case of declining of said supply voltage the switching threshold becomes correspondingly smaller, and said predetermined offset from the supply voltage remains constant, and in the case said supply voltage abruptly subceeds said reference voltage, said detection circuit sends said detection signal to said at least one microcontroller.