PROFIBUS ® is a worldwide standard for transmission of process data between field level devices and programmable controllers. How can I/O data and other information travel between Profibus and PROFINET CBA? At the physical level these two communication networks are completely incompatible. Profibus is at its core an RS485-based communication standard with a maximum baud rate of 12M. At the core of PROFINET CBA is Ethernet, another worldwide standard with baud rates of 100M and beyond.
Are they at all compatible at the protocol level? Profibus is I/O driven. Data is transferred as blocks of inputs and outputs which are interpreted by agreement between the Profibus Master and the Slave. PROFINET CBA is an object oriented system where any interface can be connected to any other interface. There is no hard and fast definition of a Client or Server. A device interface can be configured to supply data as a Server or consume data as a Client. Connections are made at system integration time using the connection editor at an object level between device interfaces.
Connections form the sensor bus-level to Enterprise Resource Management (ERP) and Manufacturing Execution System (MES) systems require Profibus to PROFINET CBA Gateways. Since the Profibus Master device can access all the data of the Profibus network the logical place for this gateway is the Master device usually the programmable controller. These devices will most likely be equipped with both technologies and it is reasonable to expect to find that this is where the link in these systems will be found. This is illustrated in the Figure 4. |
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