2. The error detection device according to claim 1 , further comprising a result determinator configured to: determine that a relevant sequence is same logic when each calculated hash code for each minimum unit is same; and determine that a relevant sequence is similar logic when the calculated LCS is greater than the set similarity threshold.
1. An error detection device for a programming language on a PLC (Programmable Logic Controller) automation system, the device comprising: a program preparation unit configured to prepare a program by using the programming language; a logic converter configured to convert the prepared program to a sequence; a variable filtering unit configured to remove information related to variables of the programming language in response to a user selection by removing variable information used by the program; a hash code calculator configured to detect same logic relative to the sequence by dividing the sequence into a minimum unit of a plurality of program languages, calculating hash codes according to the divided minimum unit and comparing each of the calculated hash codes; an LCS (Longest Common Subsequence) calculator configured to calculate an LCS relative to the divided sequence and detect similar logic relative to the sequence by applying the calculated LCS to an LCS algorithm; and a threshold input unit configured to set a similarity threshold of the sequence according to a user input and change the similarity threshold when either similar logic is not detected or an amount of detected similar logic exceeds the set similarity threshold, wherein the programming language comprises IEC61131-3 programming language of which a minimum unit is rung.