Abstract: A test stand having a control chamber with a fluid pressure therein for simulating an operational parameter of a device. A doser system with a controller which receives an input representing a desired pressure Px in the control chamber. The controller supplies either a first or second solenoid valve with an actuation signal to allow fluid pressure from a source to enter the control chamber or fluid from the control chamber to flow to the surrounding environment to change the fluid pressure in the control chamber form Pc to Pc'. A pressure transducer supplies the controller with a feedback signal corresponding to the actual fluid pressure Pc' in the control chamber. The controller derives an error signal (Px-Pc') to define an update for the actuation signal. As Pc' approaches Px, the duration of the actuation signal correspondingly changes to assure that the desired fluid pressure for the control chamber is achieved without exceeding the desired fluid pressure in a relatively short time period.