Diagnostic circuit for monitoring an analog-digital converter circuit

摘要

Described is monitoring of an analog-digital conversion of a measured value of at least one of a pressure gauge, a level gauge and a flowmeter. Different measured values can be provided for the analog-digital converter by means of a first microcontroller, wherein these measured values are subsequently transmitted from this first area into a second area by means of a unidirectional coupler. These values are acquired by a second microcontroller in the second area and compared with reference values that are stored in the second area or at another location. This diagnostic circuit may make it possible to detect drifts of resistances and of reference voltages, as well as a faulty analog-digital converter or a program execution error of the first microcontroller.

主权项

1. A diagnostic circuit for monitoring an analog-digital converter circuit during an input of a measured value of at least one of a level gauge, a pressure gauge and a flowmeter, comprising:
a multiplexer selecting different input signals; a first microcontroller controlling at least the multiplexer to select at least one of the input signals, the selected input signal being forwarded to an analog-digital converter for converting the input signal into a digital value; and a second microcontroller configured to compare the digital value with a stored, digital reference value for the input signal to detect a malfunctioning of the analog-digital converter.