ABNORMALITY MONITOR

PURPOSE:To suitably check the plant condition and to surely detect even in the abnormal condition where detection cannot be performed with one sensor. CONSTITUTION:The monitor has a signal input means 14 to fetch a condition signal including a trouble signal outputted from a sensor 13 of respective places of a plant 11, a data base 17 to store the checking pattern to set at least two signal states or above and conditions for each abnormal condition presumed from the plant 11 beforehand, and abnormal condition checking means 16 to check the establishment and non-establishment of a signal condition concerning the condition signal including a trouble signal in accordance with the checking pattern of the data base 17 and check the abnormal condition of the plant 11 in accordance with the fact whether or not the checked result is coincident to the conditions.