The modern vacuum applications ask more and more for constant pressures in chambers and reactors or constant gas flow to maintain certain atmospheres in those chambers. This can be done in different ways, e.g. downstream control, massflow control or as we would like to discuss now by upstream control. A very simple version of upstream control could be a limit switch controlled valve operation by just opening or closing the valve. A simple and inexpensive method with all pros and cons concerning any system requirement. As an improvement to this, modern upstream controllers are flexible and give various opportunities to justify the pressure control circle in a vacuum system. The parameters to take care of like: chamber size, pumping speed, response times, time requirements etc. are very well known by everyone who has ever designed such a control circle. The user requirements of the vacuum system combined with all these parameters result in a level of requirements of a controller and a valve as well as for the applied gauges. Those requirements may vary in such a wide range that many pressure controllers are by far out of their limits. Modern solutions for pressure controllers or upstream controllers may not cover every extreme requirement. These new and advantageous controllers give flexibility in choosing out of various gauges and allow to justify the PID parameters in a wide range that nearly most of the known applications are covered in a satisfying way.