Siemens Develops PC-based Profinet IO Software Controller for Linux Systems

With the “Softnet PN-IO Linux” software controller from Siemens, it is possible to set up open control solutions on standard PC hardware.

These solutions can then be used for a wide variety of applications. Up to 64 I/O devices can be connected to the controller; additional communication hardware is not necessary. An inexpensive link-up to field units in industrial Ethernet networks is thus available to the user. Operation of the devices via wireless LAN is also possible.

Linux systems are becoming increasingly popular in the area of industrial automation, whereby inexpensive PC-based solutions are especially attractive to machine and plant operators. The Softnet PN-IO Linux software controller developed by Siemens now makes it possible to control distributed field devices via Profinet (PN) with standard PC hardware such as the “Simatic Microbox PC”. The computer functions as a PN I/O controller. Up to 64 devices can be controlled at the same time and, for each device, 1,440 bytes are available in the input and output area. The update time in 100 Mbit full duplex mode is between eight milliseconds (16 connected field devices) and 32 milliseconds (64 connected field devices). For devices linked-up via WLAN, the update time is higher by a factor of approximately four.

The IO devices are configured with the standard tools STEP 7 or NCM PC. PN-IO Base serves as the programming interface. The structure of this C/C++ interface is comparable with the DP-Base interface, a component of the Softnet Profibus DP product. This considerably simplifies porting from existing Profibus DP master applications to PN IO controller applications. Softnet PN-IO Linux can run on open PC architectures. The Linux systems can therefore also be used for other tasks. For example, they can be used as a web server or gateway as well as for visualization or data collection.