In the application of the theory of fault detection and isolation (FDI), there is a particular area that is the detection of leaks in pipelines that carry some type of liquid. An important premise in most of these detection methods is that the flow pressure at the pipeline inlet is considered to be constant, but this premise is not fulfilled when there is a hydraulic pump at the pipeline inlet. In this paper, a solution is presented to keep the pressure constant at the entrance of a prototype pipeline built specifically for the detection of pipeline failures. It is proposed to close a control loop to regulate the pressure, this with a proportional-integral controller (PI); The handicap in this proposal is that there is a discrete element in the loop, a frequency inverter. The steps of the controller design and its implementation in the pipeline are described. The final result shows excellent performance in pressure regulation.