Application samples
EL6601, EL6614
139
Version: 4.2
This works for computers (A) and (B). The DHCPDISCOVER messages from computer (C) are accepted by
the EL6601 and relayed in computer (B) to Windows via the EtherCAT port, but Windows (B) does not route
these messages (and all other DHCP telegrams) through to the relaying Ethernet port – this function, known
as DHCP Relay Agent, is only available in the server version of Windows.
This is the normal operating case when Windows PCs configured as DHCP devices are linked with each
other.
Remedy:
• Install a local DHCP server on computer (B), taking care that no conflict arises with the superordinate
network DHCP server
• It is possible that two Windows PCs, which are configured as DHCP devices and connected to each
other, will only establish their addresses after a short time (several minutes)
6.6
Application sample - Flexible Ethernet Port
The application samples have been tested with a test configuration and are described accordingly.
Certain deviations when setting up actual applications are possible.
This sample illustrates the principle of remote access from a subordinate PC to the central EtherCAT
controller via a flexibly connected EL6601 and EtherCAT.
The following elements were used:
• IPC with Windows XP SP2
• TwinCAT 2.11 b1534
• EL6601, SN xxxx0605
The approach
The task is to commission an extensive system with EtherCAT topology. To this end frequent access to the
TwinCAT System Manager on the central PC is required. In practice the technician will primarily be at the
local terminals/EtherCAT slaves during commissioning. The central System Manager as the TwinCAT target
system should therefore be accessed from the respective coupler location via a remote PC and Ethernet.
Two mechanisms are used for this purpose:
• EtherCAT tunnels standard IP telegrams through dedicated slaves, e.g. EL6601, via the acyclic
mailbox procedure
• Via the HotConnect functionality a coupler station (c terminals) can be classified as freely
pluggable in the configuration (.tsm). Special couplers must be used for this purpose.
A freely pluggable combination of EK1101 and EL6601 (HotConnect group) can now be used as a flexible
Ethernet interface.
Possible configuration
A possible configuration is described below:
