Master pattern generation method based on control program analysis and training method for cycle analysis model

A master pattern generation method from a ladder logic of a programmable logic controller (PLC), the method comprising:

• generating, by a processor, a master pattern to be compared with contacts in the ladder logic of the PLC to determine whether each cycle is normal or abnormal, wherein
• the generating the master pattern includes:
• generating a relationship between the contacts included in the ladder logic;
• generating bars for each cycle from log data of the PLC and links for each cycle;
• calculating a statistic of the bars and links included in a plurality of cycles;
• and
• generating h master pattern based on the calculated statistic,
• the determination of whether each cycle is normal or abnormal includes:
• comparing the master pattern with input data to generate output data indicating whether there are errors for each bar and link, and
• detecting, with an artificial neural network trained using the input data and the output data, at which contact and link the error occurs with respect to data of a new cycle, and correcting the error, and
• the generating of the relationship between the contacts includes:
• removing a manual column from the ladder logic and expanding a path by searching for a step in which contact A that maintains an OFF state as usual and then changes to an ON state is used as an output contact of another step.