Overview

The TwinCAT PLC library, COMlibBC, offers function blocks and data structures for serial data communication with the Beckhoff BCxxxx bus controllers. COMlibBC supports the Beckhoff KL6xxx serial bus terminals.

COMlibBC offers blocks for byte-wise transmission and reception of data. All blocks may have multiple instances, so that a number of serial interfaces may be operated in parallel.

The serial bus terminals are available in a 3-byte version and a 5-byte version. In order not to unnecessarily load the memory of the BCxxxx bus controller, a modified ComLibBC5B library is available for 5-byte mode. Use, therefore, one of the two libraries according to the terminal hardware in use. As a rule, the 3-byte version of the serial bus terminal is supplied by the factory.

Because there are different versions of the BCxxxx Bus Controllers, there is a variation in the memory mapping of the serial Bus Terminals in 3-byte mode. For this reason, only the 5-byte mode will in future be supported. As far as possible, therefore, only use terminals in 5-byte mode. These can be ordered as KL6xxx-0020.

The PC and the bus controller BC versions of the communication library have been unified since version 2.0. Please compare to the PC documentation.