Product Overview

The WAGO 750-628​ is the Bus Extension Coupler Module of the WAGO I/O System 750, the component that lets a single fieldbus node be split physically without being split logically. In a standard 750 assembly, the fieldbus coupler or controller sits at the head of the node and drives every I/O module behind it over the internal data bus. The WAGO 750-628​ takes the place of that coupler on a downstream assembly and reconnects it, through a shielded patch cable, to the end extension module 750-627 terminating the upstream block. The result is one continuous node as far as the fieldbus coupler, the PLC and the engineering tool are concerned — no extra bus address, no gateway, no additional configuration in the controller.Physically, the WAGO 750-628​ carries two RJ-45 sockets: an input that links back towards the coupler and an output that allows the node to continue, supporting up to ten extension stages with as many as 64 I/O modules per node. Field supply and system electronics supply are fed separately and isolated from each other at 500 V, so a fault on the actuator side cannot take down the bus electronics. Two LEDs report system and field voltage, two further LEDs in the RJ-45 socket confirm error-free communication with the neighbouring blocks, and a switchable terminating resistor lets the module serve either as the last coupler in the chain or as a bridge between two assemblies.Because the extension is transparent to the host system, the WAGO 750-628​ is the standard answer whenever a machine layout, a cabinet split or a field-mounted junction box makes a single continuous I/O rail impractical.

Technical Specifications

Main Features and Advantages

Transparent extension with no address penalty: The WAGO 750-628​ extends the internal data bus rather than the fieldbus, so the host coupler and the PLC see exactly the same node they did before. There is no second fieldbus address to allocate, no additional GSD or EDS file to integrate, and no change to the process image mapped in the controller. From an engineering standpoint the extension is invisible; from a machine-build standpoint it is the difference between one long rail that has to fit and several short assemblies that can be placed wherever the machine requires.Two RJ-45 ports for chained or branched topologies: With an input and an output socket, each WAGO 750-628​ can serve as a bridge between two I/O assemblies or, with its terminating resistor switched on, as the final coupler in the chain. Up to ten stages can be linked, giving designers the freedom to place I/O where the sensors and actuators actually are — on a rotating machine section, in a separate junction box, or on the far side of a cabinet partition — instead of pulling every field cable back to a central point.Separate, isolated power domains: System electronics and field side are fed independently and isolated at 500 V. That separation is what makes the module safe to use in mixed installations, where the bus supply is clean and conditioned while the field supply is shared with contactors, valve manifolds and drives. Three outgoing power jumper contacts, each rated 10 A, let the WAGO 750-628​ distribute field power further down the assembly without additional supply modules.Diagnostics that point straight at the problem: Green LEDs report system and field voltage independently, and two LEDs inside the RJ-45 socket indicate fault-free communication with the adjacent blocks. When a node drops, that split tells a technician within seconds whether the issue is power, cable or configuration, rather than requiring a process of elimination across dozens of modules.Compact, rail-mounted and maintenance friendly: At 24 mm wide and 74.8 g, the WAGO 750-628​ occupies the same footprint as a standard I/O module, snaps onto a DIN-35 rail in any orientation, and uses WAGO’s CAGE CLAMP spring connections for tool-free, vibration-proof wiring from 0.08 to 2.5 mm². Vibration resistance of 4 g and shock resistance of 15 g make it suitable for mobile machinery and marine installations.