The ETC Unison ERE4 is an external processing rack designed to expand the capabilities and I/O capacity of a Unison architectural lighting control system. This unit serves as a remote, centralized hub for connecting low-voltage control devices, such as wall station keypads, occupancy sensors, and daylight harvesting photocells, and for outputting control signals to relay panels and dimming racks. It effectively extends the brain of the Unison system beyond the main processor, allowing for a distributed topology that simplifies wiring in large or complex buildings like theaters, churches, and corporate facilities. The ERE4 processes these inputs and executes the control logic programmed into the system, enabling sophisticated lighting scenes, schedules, and automated responses based on user interaction or environmental conditions.

The rack is designed for reliability and flexibility in system design. It houses multiple plug-in modules that provide specific types of inputs or outputs, such as binary inputs for switch closures, 0-10V DC analog inputs for sliders or sensors, and relay driver outputs for controlling circuit breakers or motorized shades. This modularity allows system designers to tailor the I/O configuration precisely to the needs of each installation without overspending on unused capacity. The ERE4 communicates with the primary Unison processor via a dedicated, high-speed control network, ensuring fast and deterministic response times for all lighting commands. This distributed approach localizes control wiring, reducing long home-run cable pulls back to a central location and improving overall system reliability and serviceability.

Housed in a sturdy, vented metal enclosure, the ERE4 is built for installation in electrical closets or equipment rooms. It is designed to operate in typical commercial environmental conditions and includes features for proper thermal management. Integration and programming are performed using ETC's proprietary software, which provides a unified interface for configuring the entire Unison system, from the main processor down to each I/O point on the remote racks. The ETC Unison ERE4 External Processing Rack is, therefore, a critical expansion component that empowers lighting control systems to scale efficiently, accommodating a vast array of control devices and loads while maintaining the robust performance and intuitive operation for which the Unison platform is known.