Automated pigging systems need a control system for the control of the various steps of the pigging operation. This is effected by a "SPS" (stored program control). So the switch position of all stations and the position of the pigs can be controlled at any time. The elements of the pigging system can be connected to the control unit either conventionally or via a bus system. When programming the control system the knowledge of the programmers is most important in order to grant a smooth pigging process. I.S.T. has more than 35 years of experience in development of automated process control systems.