Closed-loop fluid flow controls are a way to set the desired fluid flow rate from the script in the panel machine.
Unlike regular commercial flow meters or flow controls, ours is designed for the short spray times and the spray gun cycling on and off.  The on times may be as short as 200ms and then seconds of dwell time.  This control can stop and restart on the next stroke without drifting out of the operating band as general purpose devices do.