In one example in accordance with the present disclosure, a fluidic die is described is described. The fluidic die includes an array of fluid actuators grouped into zones. Each zone includes a number of fluid actuators and at least one fault detection device. The fault detection device includes a comparator to compare at least one of a representation of a supply voltage and a return voltage supplied to the zone against a voltage threshold. The fault detection device also includes a fault capture device to store an output of the comparator.