Abstract. Control of technological processes of coal preparation takes place in the presence of wide disturbances. An important problem is the choice of the controller which is robust for a variety of disturbances. No less important problem in the control process is the tuning of the controller parameters. In the paper the analysis of influence of changes in object model parameters on the course of the controlled value was carried out. For the controller settings, calculated according to model parameters research was carried out on object with other values of parameters. In the studies a sensitivity analysis method was used. The sensitivity analysis for the three methods of tuning PI controller for control systems of coal preparation processes characterized by dynamic properties of the inertial element with time delay was presented. Considerations were performed at various parameters of the object on the basis of the response of the control system for a constant value of the set point. The assessment of the considered tuning methods based on selected indices of control quality was realized.One of the primary tasks of the control system is to maintain the value of the controlled variable (process output) at the desired level. An important problem from the point of view of the control quality is also getting the appropriate course of the controlled variable and reduce the influence of disturbances running on the system. Compliance with these requirements may be accomplished by an appropriate selection of the structure of the controller and its settings. Many methods of tuning the controller use a dynamic model of a control object (determined on the basis of dynamic characteristics of the controlled process). The description of the properties of the dynamic process by using a mathematical model is helpful in the design of the control system. Knowing the dynamic model and its parameters we can analytically determine the controller settings for the assumed criterion of the control quality. Different processes with the same dynamic properties can be described by a dynamic model of the same structure which differs in only parameter values. Such an approach makes it possible to apply the same type of controller in control systems of various industrial processes. This also applies to the processes of coal preparation.The dynamic properties of many processes of coal preparation can be characterized by the inertial model of the first order (described time constant T) with time delay W [1-4].The PI controllers have two tuning parameters to adjust: the proportional gain (kr) and integral time (Ti). One of the basic methods of tuning of the PI controller is the method of Ziegler-Nichols of the identification test [5]. The Z-N method may be the initial method of tuning for many processes of the coal preparation where the dynamics has the properties of the a Corresponding author: rkaula@polsl.pl , 010 (2016)