Sync/Freeze functionality

Sync is used for the simultaneous outputting of outputs for several slaves, Freeze is used for reading in inputs from several slaves simultaneously.

The process in TwinCAT with FC310x and Bus Couplers (in K-Bus synchronous mode) would therefore be as follows (see the Synchronisation section):

• The outputs are written at the beginning (I/O at the start of the task) or the end (I/O not at the start of the task) of the task cycle
• This will start the PROFIBUS cycle
• A Sync/Freeze telegram is sent at the start of the PROFIBUS cycle
• This will cause the Bus Couplers to start a K-Bus cycle with the outputs from the last task cycle and transfer the inputs from the last K-Bus cycle
• The master will then send the current outputs to each slave and pick up the transferred inputs
• The inputs are read at the start of the next task cycle
• etc.

Outputs and inputs are therefore always one cycle old.

For the FC310x the operation mode is to be set on the master's "FC310x" tab (for TwinCAT 2.8 and TwinCAT 2.9) to "DP/MC (Equidistant)". For the boxes that are to be operated with Sync/Freeze, the Sync/Freeze enable flag is to be clicked on these slave's Profibus tab. The master always uses group 1 for the Sync/Freeze synchronization.