Sunday, January 23, 2011

Topic of the week!

Week 2: Ethernet Communication Data Exchange between S7-1200 and S7-200
Automation task:
Deterministic data exchange (e.g. for time synchronization) shall be enabled between an S7 200 master controller and several S7-1200 slave controllers.

The S7-200 controller is configured using the STEP 7 Micro/WIN V4.0 SP7 programming user interface.
The S7-1200 compact controllers are configured using the STEP 7 Basic V10.5 SP2 programming user interface.

Automation solution:
Common basis for data exchange between S7-1200 and S7-200 via Industrial Ethernet is the S7 communication protocol. For the S7 communication the S7-1200 offers the passive server functionality which provides read or write access to data. In S7-200 the configuration process occurs as a client via the Ethernet wizard in STEP 7 Micro/WIN V4.0. With the Ethernet wizard the respective connection partner as well as the exchanged data is established for both sides (client and server). A maximum number of 8 simultaneous connections can be configured with the Ethernet wizard. The deterministic data exchange with clock time synchronization for maximal 8 server is shown.

Figure 02

Client and server have one send and one receive area. For S7-200 these areas are created in the V-memory (VB_Send and VB_Receive). For the S7-1200 the data blocks are used (Receive_DB and Send_DB). At a synchronization request the client reads the system time and sends it to the first server together with the user data. This server synchronizes its system time with the received clock time of the client. The user data of server 1 is then received. This user data of server 1 is then saved at a given location in the variable buffer of the client. This procedure is repeated with the subsequent server. After the data exchange between client and the last server the client starts the data exchange with server 1.

Need to know more?

Check it out at Siemens IA/DT Support

*All information are extracted from Siemens IA/DT Support Website

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