Modem Connection between S7-300 Stations via serial CPs
A frequent task is to transfer small to medium size data volumes from one S7-300 station to another S7-300 station as simply and cost-effectively as possible. Communication of both controllers should run via a telephone system so that the distance between both stations plays a secondary role for the configuration. The controllers are connected to the telephone system via modems and serial CPs.
For solving the automation task, a modem connection is established between both stations. The modems are controlled by the S7-300 CPU via serial communiction groups CP 340 or CP 341.
This application uses the specially developed function blocks FB 100/FB 101, which after specifying some parameters dial into the remote partner station via a dialup network, and send data to or receive data from the partner station.
The pictorial schematic of this application is illustrated in the figure below:
Two configurable communication blocks were developed based on this principle. The FB 100 "Mod_CP340" is used for communication between CP 340 and modem, and FB 101 "Mod_CP341" for communication between CP 341 and modem. Using these blocks, a connection between both stations can be established and data can be exchanged (in this example in form of message texts).
The following figure shows the hardware setup of the application:
|08/2006||Standard software (FB2, FB3, FB7, FB8) updated|
Return telegram added
Usage of modems SINAUT MD3
CP 340, CP 341, Modem communication, FB 100 "Mod_CP340", FB 101 "Mod_CP341", ISDN, analog, dialup connection, serial communication