On the Communication Board CB 1241 RS 485, the following standard protocols are available:

• ASCII:
  For interfacing to third-party systems with simple transmission protocols, e.g. protocols with start and end characters or with block check characters. The interface handshake signals can be queried and controlled via the user program.
• Modbus:
  For communication according to the Modbus protocol with RTU format:
  • Modbus Master:
    Master-slave interfacing with SIMATIC S7 as master.
  • Modbus slave:
    Master-slave interfacing with SIMATIC S7 as slave; message frame traffic from slave to slave not possible.
• USS drive protocol:
  Instructions for connection of USS protocol drives are specifically supported. In this case, drives exchange data over RS485. It is then possible to control these drives, and to read and write parameters.

Additional drivers can also be downloaded.

Parameterization

The parameterization of the Communication Board CB 1241 is particularly user-friendly and simple with STEP 7 Basic:

The user specifies the properties of the module by means of a parameterization environment integrated into STEP 7 Basic.