METHOD OF DETECTING NOISE DISAPPEARANCE AND DETECTING DEVICE THEREFOR

摘要

A method of detecting a noise disappearance of instruments, etc. in various instrumentations in a chemical plant or the like and a detecting device therefor. Detection values as being outputs from a detector (1) are input into a data store (3) via a data collector (2). Input into a processor (4) are a detection value as being a value (Sold) of the previous time from the data storer (3) and further a detection value as being a newest value (Snew) from the data collector (2). In the processor (4), an absolute difference between the newest value (Snew) and the value of the previous time (Sold) is processed. When this difference is smaller than a preset value, a count number (C) of a counter (5) is stepped up, whereas, when this difference is larger than the preset value, the count number (C) is cleared. When an output signal from the counter (5) exceeds a predetermined threshold value, this case is regarded as occurrence of a noise disappearance, whereby a trigger signal (T) for actuating a notifier (7) is output from a limiter (6).