Plant contamination monitoring device esp. for fungi - measures temp. with compensating nonlinear voltage-to-frequency conversion

摘要

A warning device monitoring the contamination of plants by parasitic growths, esp. fungi, consists of a moisture and temp. sensor with a digitiser, for the temp. signal and a counter driving an alarm. The analogue-to-digital conversion is performed more simply and reliably and using a non-linear characteristic enabling the measurement to correspond to the parasitic development process. The conversion is achieved using a non-linear voltage-to-frequency converter contg. a voltage dependent sawtooth waveform generator. The decay edge of the generator oscillation is varied in shape according to the necessary degree of non-linearity. The alarm device responds to the counter reaching a defined number of impulses from the analogue-to-digital converter.(DS).