US Patent 10180050 Select fire switch control system and method

A select fire system and method for controlling operations in a gun string assembly includes perforating guns and switch subs mechanically connected in the gun string assembly. Each of the switch subs includes a switching element, input links and output links. The switch subs and perforating guns communicate with each other through the input and output links. The switching elements keep track of the state of the sub and switches states based on trigger conditions such as environment conditions, perforating gun conditions, or input conditions from surface.