Basic Principles Of Function And Commissioning - Beckhoff EL6692 Documentation

Commissioning
5.4

Basic principles of function and commissioning

The EL6692 is used for data exchange between two EtherCAT circuits. Predefined process data can be
copied from one fieldbus side to the other. Status variables provide information about missing data and the
status of the other side.
If distributed clocks are used in both EtherCAT circuits the EL6692 can also be used for synchronizing the
two timebases. In this case the user has to define which side has the reference clock with the higher priority.
The EL6692 will then send a reference clock correction value to the EtherCAT master with the lower priority.
Further information about operating principle and the application of distributed clocks can be found in the
associated documentation at www.beckhoff.com.
The EL6692 consists of two EtherCAT slaves in one case: the EL6692 on the primary side (terminal bus)
and the EL6692-0002 on the secondary side with network cable connection. Both slaves have their own
power supplies and are thus independently operational. The primary side is supplied with 5 V via the E-bus,
the secondary side with 24 V via the external connection.
Data transfer in the EL6692 is handled by a microcontroller that exchanges data in both directions in free-
running mode. The transfer time from one side to the other depends on the number of bytes. The
configurable "DC synchronous" mode does not apply to the process data exchange, but to the application of
the EL6692 for distributed clock synchronization. The EL6692 does not deal with throughput control, i.e. the
user has to ensure (through suitable programming) that the EL6692 is not supplied with more data than it
can process, e.g. by using a higher-level handshake. The limit values [} 117] specified below must be
complied with.
The EL6692 supports EoE, Ethernet over EtherCAT. The means that not only cyclical process data can be
transported from the EtherCAT side to the other side, but also standard Ethernet frames arriving at the
EL6692 via mailbox communication. Since TwinCAT and the connected EtherCAT environment act as a
virtual network card, Windows handles the routing of IP frames (e.g. 192.168.2.1) to the EL6692, in order to
transport the frames to the EtherCAT system on the other side. Further information can be found in the
EL6601/EL6614 documentation. No special EL6692 configuration is required.
• Application notes for EL6692 [} 110]
• Application notes for EL6692-0002 [} 112]
• General application notes [} 110]
EL6692 support in Beckhoff TwinCAT
Full support for distributed clocks synchronization with the EL6692 is provided from TwinCAT ver-
sion 2.11 or higher. Previous versions are limited to process data exchange.
Application notes for EL6692, primary side
The default state of the EL6692 after reading/creation is
• DC support off - FreeRun
• No process data variables preconfigured
• No distributed clocks information data; see Process Data tab in the fig. Default process image for
EL6692.
110 Version: 3.2 EL6692