System Overview - Beckhoff EJ18 Series Manual

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System overview

Electronically, the EJxxxx EtherCAT plug-in modules are based on the EtherCAT I/O system. The EJ system
consists of the signal distribution board and EtherCAT plug-in modules. It is also possible to connect an IPC
to the EJ system.
The EJ system is suitable for mass production applications, applications with small footprint and applications
requiring a low total weight.
The machine complexity can be extended by means of the following:
• reserve slots,
• the use of placeholder modules,
• linking of EtherCAT Terminals and EtherCAT Boxes via an EtherCAT connection.
The following diagram illustrates an EJ system. The components shown are schematic, to illustrate the
functionality.
Fig. 6: EJ system sample
Signal distribution board
The signal distribution board distributes the signals and the power supply to individual application-specific
plug connectors, in order to connect the controller to further machine modules. Using pre-assembled cable
harnesses avoids the need for time-consuming connection of individual wires. Coded components reduce
the unit costs and the risk of miswiring.
Beckhoff offers development of signal distribution boards as an engineering service. Customers have the
option to develop their own signal distribution board, based on the design guide.
EtherCAT plug-in modules
Similar to the EtherCAT terminal system, a module strand consists of a Bus Coupler and I/O modules.
Almost all of the EtherCAT Terminals can also be manufactured in the EJ design as EtherCAT plug-in
modules. The EJ modules are directly attached to the signal distribution board. The communication, signal
distribution and supply take place via the contact pins at the rear of the modules and the PCB tracks of the
signal distribution board. The coding pins at the rear serve as mechanical protection against incorrect
connection. Color coding on the housing facilitates distinguishing of the modules.
EJ18xx Version: 1.5
System overview
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