NRG Controllers Carlo Gavazzi NRG Controllers are the devices in the NRG BUS chain. The NRG products interface directly with the main controller of the system through different communications. The series includes the NRGC I/O module, NRGC-PN controller, and NRGC-EIP controller variants. These NRG products are just a facilitator of the communication between the main controller and each individual RGxxN solid-state relay in the system. The devices operate at 24VDC and come with LEDs on the front facade. These LEDs give a visual indication of the status of the NRG products of any ongoing communication. This communication is done with the Main Controller (COM), the RGxxN on the BUS chain (BUS), and an alarm condition related specifically to the NRG products.