Due to their complexity, production units and equipment in petrochemical plants need to be controlled by advanced process controllers (APC). The optimality of APC control is closely connected with the setting of constraints, while their inappropriate setting leads to a loss of the generated profit. In order to inform the operator in time, we create a tool that analyses the effectiveness of constraints setting. We design a copy of the APC model as a static optimization problem with the implementation of soft constraints. Two methods are employed: local sensitivity analysis using Lagrange multipliers and non-local sensitivity analysis. An ordered list of recommendations is created for plant engineers, providing information on the effectiveness of constraint setting for a single point of operation or during a specific time interval.