JPS57184981A - Trouble diagnosing device - Google Patents

Abstract

PURPOSE:To enable to perform an on-line operation by means of a simple constitution, by a method wherein, in a spectrum analysis type trouble diagnosing device, a reference data is stored in a memory through multiplication of data at a normal time of a device to be diagnosed by a given mask function to compare it with a sample data. CONSTITUTION:An electric signal from a 3-phase induction motor 10, being a device to be diagnosed, is applied to a level conversion filter circuit 21 to regulate an amplitude and a band. The signal of the circuit 21 is sampled (22) and A/D-converted (23). The converted data is stored in a sample memory 24 which can read and write, and is decomposed into a frequency component by a computing circuit 25. A reference data is stored in a reference data memory 26 through multiplication of a frequency spectrum component at the normal time of the device 10 by a given mask function, and is written and protected. The data of the circuit 25 is compared with the data of the circuit 26 by a digital comparator 27, and if a deviation is large, an abnormal signal (b) is outputted. The simple hard constitution permits high-speed diagnosing of a trouble on an on-line.