The invention relates to an apparatus for the generation of a program for a programmable logic controller having a programming input unit for the selection and compilation of a plurality of symbols, a generation unit for the generation of a program code for the programmable logic controller from an arrangement of symbols compiled at the display unit of the programming input unit. In accordance with the invention an investigation unit for investigating the resulting possible influences of input signals of the programmable logic controller, onto output signals of the programmable logic controller at the actuator outputs from the arrangement of symbols generated by the program code or compiled at the display unit of the programming input unit is provided. In accordance with the invention an implementing unit for implementing the possible exertion of influence in a matrix and a display unit for the display of the matrix are also provided. The invention further relates to a programming device for a programmable logic controller having such an apparatus for the generation of a program, a corresponding method for programming a programmable logic controller and a corresponding computer program product.