Product Description:

The EJ9404 is a power-supply plug-in manufactured by Beckhoff for the EJ EtherCAT Plugins series. Installed alongside control and I/O slices, the unit reinforces the internal backplane that distributes operating power across an EtherCAT stack. Instead of handling field signals, it injects energy onto the rail so densely populated carrier boards retain timing accuracy and stable logic voltage during peak demand. By supporting the 3.3-volt plane that links every slice, the module helps automation cells keep sensors, microcontrollers, and communication ASICs within their specified input range even when bus traffic and load change rapidly.

The device can supply up to 12 A to the shared line, which it stabilizes at 3.3 V for logic-level electronics. The unit uses a common ground, simplifying board layout by avoiding isolated returns. Its designation as an Additional E-Bus Supply indicates that it feeds power without altering protocol data. Incoming power must originate from a circuit classified as SELV/PELV, meeting extra-low-voltage safety limits for operator-accessible panels. An optional reset input can be wired to supervisory logic when controlled brownout recovery is required. This input allows downstream modules to restart in a predictable sequence after an interruption instead of returning to operation at different times.

Mechanical integration follows a standard installation position, allowing the device to be placed in any orientation permitted by the carrier without concerns about derating. The housing locks directly onto a Signal Distribution Board, eliminating loose wiring and reducing assembly time. Locating this supplementary power point close to high-demand slices strengthens the E-bus feed and improves voltage stability during simultaneous switching events. This arrangement also reduces the distance over which the additional current must travel before reaching heavily loaded modules. The direct board connection keeps the installation compact while preserving access to neighboring EtherCAT plug-in modules. Stable backplane power helps adjacent control and I/O electronics maintain normal communication performance as their loads change.