EJ8xxx - Signal-Distribution-Board for standard EtherCAT plug-in modules

Design of power supply

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Power supply
A SELV/PELV power supply must be used to supply power for the EJ coupler and modules. Couplers and modules have to be connected to SELV/PELV circuits exclusively.

The signal distribution board should have a power supply designed for the maximum possible current load of the module string. Information on the current required from the E-bus supply can be found for each module in the respective documentation in section “Technical data“, online and in the catalog. The power requirement of the module string is displayed in the TwinCAT System Manager (see Current consumption of the EJ modules from the E-bus).


E-bus power supply with EJ1100 or EJ1101-0022 and EJ940x

The EJ1100 Bus Coupler supplies the connected EJ modules with the E-bus system voltage of 3.3 V. The Coupler can accommodate a load up to 2.2 A. If a higher current is required, a combination of the coupler EJ1101-0022 and the power supply units EJ9400 (2.5 A) or EJ9404 (12 A) should be used. The EJ940x power supply units can be used as additional supply modules in the module string.

Depending on the application, the following combinations for the E-bus supply are available:

E-bus power supply with EJ1100 or EJ1101-0022 + EJ940x

In the EJ1101-0022 coupler, the RJ45 connectors and optional ID switches are external and can be positioned anywhere on the signal distribution board, as required. This facilitates feeding through a housing.


Additional E-bus power supply with EJ940x

The power supply modules EJ940x can be used as additional supply modules in the module line.

When adding an additional power supply module in an EJ line only the supply voltages for the E-bus (UEBUS) have to be separated into two or more nets. The E-bus GND is common for all EtherCAT plug-in modules in the design.

As examples, two designs with additional power supply modules are shown below.

Example with Coupler EJ1100, with integrated power supply (2.2 A), additional power supply with EJ9404 (12 A)
Example with Coupler EJ1101-0022, power supply module EJ9400 (2.5 A), additional power supply with EJ9400 (2.5 A)