A motor-driven and controlled packaging machine for forming pouches from a web of material. The controls allow the machine to be run with either a continuously or intermittently advancing web. Seal bars are mounted on moveable carriages which move with the web as they form the seals. A web unwind is servo controlled to minimize the amount of festoon section needed when operating in intermittent mode. Each registration-related component of the machine has a dedicated sensor for independently registering each component with the web. Accordingly, the machine may regain registration with minimal web waste and can be quickly and easily repositioned for different pouch sizes.