RevPi Gate modules have control lines on the PiBridge that can be used to set them into bootloader mode to perform firmware updates via the PiBridge. If a RevPi Gate is now connected to the power supply and the PiBridge is connected to a RevPi Core that is not yet connected to the power supply, the RevPi Gate switches to this bootloader mode. In this mode, the power LED doesn’t light up and the module cannot exchange data via the PiBridge.
In order for the RevPi Gate module to work properly, please make sure that the RevPi Core and the RevPi Gate module are always connected to power simultaneously.
In a control cabinet, this is usually not a problem as both devices are connected to the same power supply and therefore receive electricity simultaneously when the power supply unit is switched on.