You are currently viewing the content available in Vietnam. If you are looking for information for another region, please select the correct country from the top-left dropdown in the page and 'Navigate to Browse FAQs' in the Support menu.
Why do I get the error code OL9-21581 Illegal Modbus function code when trying to connect to the Concept simulator?
One possible reason is the package of Concept installed is Concept S or Concept Small. The small version of Concept does not contain the IEC 32 simulator.