TwinCAT SOFTNET
S7 Communication Server
The TwinCAT S7 Communication Server links the Siemens S7 Industrial Ethernet world to TwinCAT, permitting the extension of existing plant by means of PC based control technology. The server is implemented as a ring Windows service, and consists primarily of a gateway between ADS (Automation Device Specification) and SOFTNET S7. This allows the ADS functions to be used to execute read and write accesses to flags and data blocks in the Siemens S7 PLC.
Within the context of TwinCAT software, the SOFTNET S7 is a pure software driver, able to be described as a virtual field (automation) device. It provides an ADS interface for other communication partners such as other virtual field devices or Windows programs. The use of the ADS standardizes access to the TwinCAT SOFTNET S7 device, placing it in the group of available virtual field devices.
TwinCAT is the active device, and initiating read and write applications through the supplied IEC 61131-3 PlcSOFTNET S7 library from the TwinCAT PLC. Alternatively access becomes possible through a visualization program via ADS OCX/DLL.