On the basis of the information given in VDI/ VDE 3508 (in particular Section 7)@ this guideline gives a hands-on description of acceptance tests of closed loop control in power plants. While it provides recommended values for the control performance that can be achieved for the entire system in various operating modes@ it will not generally allow to dispense with a detailed analysis of individual cases. This guideline deals with acceptance tests of control loops and not with acceptance tests of steam generators@ turbines or other lots. The types of power plants analysed are large steam power plants with hard coal- or lignite-fired once through steam generators.