{"id":"iec-concat","model_id":"CONCAT","name":"CODESYS CONCAT","summary":"CONCAT is a function in the CODESYS Standard library that joins two strings into one. It takes two STRING(255) inputs, STR1 and STR2, and returns a single STRING(255) containing STR1 immediately followed by STR2. In the documented example, CONCAT('SUSI','WILLI') returns 'SUSIWILLI'.","study_notes":["Declared as FUNCTION CONCAT : STRING(255).","Return value is limited to 255 characters; if the result does not fit into 255 bytes it is silently truncated and no error is produced.","Both inputs STR1 and STR2 are of type STRING(255).","Example in ST: VarSTRING1 := CONCAT('SUSI','WILLI'); gives the result 'SUSIWILLI'.","The document shows an InOut section with no entries."],"safety_notes":[],"sources":[{"url":"https://infosys.beckhoff.com/content/1033/tcplclib_tc2_standard/74411019.html","title":"Beckhoff Information System","accessed":"2026-10-26"},{"url":"https://content.helpme-codesys.com/en/libs/Standard/Current/String-Functions/CONCAT.html","title":"CODESYS Group","accessed":"2026-10-26"}],"verification":{"status":"source_checked","checked_at":"2026-10-26","values":9,"method":"llm_source_check"},"updated_at":"2026-10-26","type":"instruction","spec":{"language":"structured_text","code":"CONCAT","group":"String Functions","syntax":"CONCAT(STR1, STR2)","parameters":[{"name":"STR1","data_type":"STRING(255)","description":"String 1 to be concatenated, max. 255 characters."},{"name":"STR2","data_type":"STRING(255)","description":"String 2 to be concatenated, max. 255 characters."}],"dialect":"CODESYS","related":[],"standards":[]},"url":"https://machineschema.com/instruction/iec-concat","license":"https://creativecommons.org/licenses/by/4.0/"}