Patent ID: 7928742

Claim:
A measurement transmitter, comprising: a microprocessor having a reset input and a clock signal output for providing a periodic clock signal; a monitoring circuit having a clock signal input and a reset output; a current controller for output of a measurement signal current representing during measurement operation a measured value in a first band range and signaling a malfunction when outside of the first band range and a comparator circuit having a first input, which is connected via a lowpass with the reset output of said monitoring circuit, a second input, on which a reference voltage is applied, and an output, which is connected with an input of said current controller, wherein: the clock signal input of the monitoring circuit is connected with the clock signal output of said microprocessor; the reset input of said microprocessor is connected with the reset output of said monitoring circuit; in case of an absence of the clock signal, a reset signal is periodically issued on the reset output of said monitoring circuit; following repeated output of the reset signal, voltage at the first input of the comparator exceeds the reference voltage, so that, present at the output of the comparator, is a control signal, which causes the current controller to issue an error signal current outside of the first band range; and said comparator circuit comprises an operational amplifier.