• Existing systems are to be expanded or modernized.
• Controllers and systems from different manufacturers are to be combined – e.g. when new plants are being installed.

Modbus is based on a master/slave or server/client architecture which can be implemented in different ways within the PCS 7 environment. Selection depends, on the one hand, on the individual systems and controllers which shall communicate with each other, since not all controllers and systems support all types of Modbus protocols (PtP or TCP). On the other hand, the type of interfacing also arises from the specific the plant network, i.e. the allocation of communication partners as master or slave.

Solution  
In the following sections we present you some fully described solutions based on PCS 7 standard functions and add-on products which are suitable to significantly reduce your engineering costs and efforts. You may use them either for new configurations or integrate them in existing projects. All required hardware and software components are Siemens products which, as always, guarantee best compatibility, state-of-the-art technology and upgradability. The PCS 7 standard and the Modbus standard are followed without exception.

Validity
This application description refers to SIMATIC PCS 7 V7.1 SP2 or higher.

Core topics of this application description
The two solutions described in the following for the configuration and parameterization of Modbus PtP in PCS 7 systems differ with regard to the use of the Modbus functions either as master or slave.

• PCS 7 Modbus PtP master
• PCS 7 Modbus PtP slave

Each of these variants is considered under the following aspects

• Advantages
• Required hardware and software
• Installation and setup
• Configuration
• Performance data

Furthermore, each solution not only describes the connection to a singular PCS 7 system, but also the connection to a redundant system.

Your benefits at a glance

• Easy configuration and standardized solutions for the complete lifecycle of the plant
• Optimized communication performance
• Minimum recovery time after communication failure
• Complete block library with help functions in German and English
• Configuration software with help functions in German and English

Downloads

Contents of the downloads	Download
Documentation  Modbus PtP - Standardized communication of PCS 7 with Third-Party Systems SIMATIC PCS 7 V7.1

History

Version	Modification
07/2012 V1.0	First Release

Additional Keywords
serial communication, coupling, data link, interface, interfacing, link-up, linking, integration,