4. An error detection method for a programming language on a PLC (Programmable Logic Controller) automation system, the method comprising: preparing a program using the programming language; converting the prepared program to a sequence; removing information related to variables of the programming language in response to a user selection by removing variable information used by the program; detecting 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; comparing each of the calculated hash codes; calculating an LCS (Longest Common Subsequence) relative to the divided sequence; detecting similar logic relative to the sequence by applying the calculated LCS to an LCS algorithm; and setting a similarity threshold of the sequence according to a user input and changing 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.
4. An error detection method for a programming language on a PLC (Programmable Logic Controller) automation system, the method comprising: preparing a program using the programming language; converting the prepared program to a sequence; removing information related to variables of the programming language in response to a user selection by removing variable information used by the program; detecting 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; comparing each of the calculated hash codes; calculating an LCS (Longest Common Subsequence) relative to the divided sequence; detecting similar logic relative to the sequence by applying the calculated LCS to an LCS algorithm; and setting a similarity threshold of the sequence according to a user input and changing 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. 5. The error detection method of claim 4 , further comprising: determining that a relevant sequence is same logic when each calculated hash code for each minimum unit is same; and determining that a relevant sequence is similar logic when the calculated LCS is greater than the set similarity threshold.