Overview

The TwinCAT PLC library COMlib supplies function blocks and data structures for serial data communication. COMlib supports the Beckhoff KL6xxx serial bus terminals.

The COMlib3964RBC communication library extends COMlib to implement an error-protected protocol for the transmission of any type of data. A checksum in combination with repetition of data telegrams in the event of an error are used for error protection.

The RK512 protocol is used to transmit data blocks such as are used in Siemens controllers. The COMlibRK512BC communication library uses the 3964R protocol for this purpose, and handles the telegram traffic that it requires. The user only has to parameterize the RK512 function block.

The "Serial Communication RK512" communication package contains all the necessary libraries. It supports the transmission of data blocks with a length of up to 128 data words.

The documentation for the PLC-Library Serial Communication COMlibBC provides a basis for understanding this communication process.