PROFINET CBA OVERVIEW

PROFInet runtime communication uses TCP/IP, COM, DCOM and RPC as shown in Figure 1. The TCP/IP stack is any standard TCP/IP communication stack. COM and DCOM are Component Object Model technologies as described by the Microsoft standards. RPC (Remote Procedure Call) is a standard communication structure defined by the Open Software Foundation (OSF).

PROFInet does not typically include node configuration and initialization over the network. In fact vendors are encouraged to maintain all the current proprietary interfaces for configuration to keep the user investment in training and tools. What PROFInet does require is that these tools be revised to include an interface to generate a XML description file. This description file is to include the interfaces present in the device after configuration.

PROFInet is based on the Microsoft DCOM (Distributed Component Object Model) architecture and its predecessor COM (Component Object Model). These object distribution architectures encapsulate and manage data and provide external interfaces to the outside world in a fashion that allows Clients and Servers to access data without knowledge of the underlying data structure. COM and DCOM are Microsoft Windows technologies and are found in all windows versions since Windows 95^®.

It should be no surprise to you that PROFInet is an object-based technology. Encapsulating automation data into objects is a well-known practice used by other application layer protocols like EtherNet/IP™ and DeviceNet™. Objects allow developers to separate the data implementation from the presentation of the data to the outside world. Object implementation focuses attention on the functionality of the object instead of the minutiae of the implementation. If you are not a software developer you may not realize how important this concept is.