SYSTEM FOR COMMUNICATING DIAGNOSTIC DATA IN AN INDUSTRIAL CONTROL SYSTEM

A system and corresponding method for communicating non-I/O data between components of an industrial control system (ICS) including control or automation devices and a programmable logic controller. The method includes the steps of: having one of the components, such as a control or automation device, transmit the non-I/O data formatted as a message frame in the same way as a I/O data is formatted as a message frame, including having a message type identifier to identify that the message frame bears non-I/O data; and having another of the components, such as the programmable logic controller, receive the encapsulated non-I/O data as a message frame, wherein the receiving component identifies the non-I/O data based on the message type identifier conveyed with the message frame and extracts the non-I/O data from the message frame. The transmitting component transmits the non-I/O data over a field bus such as a PROFIBUS, INTERBUS, DEVICENET, CAN, or CAN OPEN types of field bus. The message type identifier can also indicate either the sender or both the sender and the intended recipient. The components of the ICS that communicate non I/O data each include a translator module to encapsulate and de-encapsulate the non-I/O data from (virtual I/O) message frames, based on the message identifier pre-determined to correspond to the non-I/O message data.