Ads (Acyclic Services); Fig. 31 Twincat Task, Dp Cycle And K-Bus Cycle Sequence - Beckhoff EL6731 Documentation

Parameterization and commissioning
5.1.4.2 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 sequence in TwinCAT with FC310x / EL6731 and Bus Couplers (in K-bus synchronous mode) would
therefore be as follows (see section Synchronization [} 41]):
• 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.
Fig. 31: TwinCAT task, DP cycle and K-bus cycle sequence
On the FC310x/EL6731, set the Operation Mode on the "FC310x" or "EL6731" (for TwinCAT) tab of the
master to "DP/MC (equidistant)". At the boxes to be operated via Sync/Freeze, click the checkbox Sync/
Freeze enable on the slave's Profibus [} 96] tab. The master always uses group 1 for the Sync/Freeze
synchronization.
5.1.5

ADS (acyclic services)

5.1.5.1 ADS Interface
All acyclic data are transmitted to or from the FC310x/EL6731 via ADS-Read, ADS-Write or ADS-Write-
Control. The FC310x/EL6731 has its own Net ID and supports the following ports:
Port Description
200 Addresses the FC310x/EL6731 itself, i.e. data stored locally on the FC310x/EL6731, for
which usually no additional bus access is required.
0x1000 - 0x107E This addresses a connected PROFIBUS device, with the address calculated from
port-0x1000; this always involves a bus access
ADS-Read
An overview of the IndexGroups/IndexOffsets supported by the FC310x/EL6731 during ADS-Read is
provided below.
42 Version: 2.8 EL6731