Programmable logic controller, in particular for controlling an installation, comprising a memory, wherein the programmable logic controller is connectable to the installation by means of a technical data link, wherein the programmable logic controller is connectable to a computing unit by means of a further technical data link, wherein a simulation program is executable on the computing unit, - wherein the programmable logic controller has a process image (PA Anlage, PAA Anlage, PAE Anlage) of the installation, the process image (PA Anlage, PAA Anlage, PAE Anlage) consisting of a process input image and a process output image, the process input image being transferred from the installation to the programmable logic controller and containing determined sensor data and/or positions of actuators that are readable by means of sensors and/or measured operating variables of electric machines of the installation, and the process output image being transferred from the programmable logic controller to the installation and containing commands for positioning actuators and/or commands for activating sensors, - wherein an extended process image (c-PA erw_i, c-PAA erw_i, c-PAE erw_i) has at least one copy of the process image (PA Anlage, PAA Anlage, PAE Anlage), - wherein the memory is provided for storing the extended process image (c-PA erw_i, c-PAA erw_i, c-PAE erw_i) and the process image (PA Anlage, PAA Anlage, PAE Anlage), - wherein the extended process image (c-PA erw_i, c-PAA erw_i, c-PAE erw_i) is provided for the simulation program, the extended process image (c-PA erw_i, c-PAA erw_i, c-PAE erw_i) being available in a data format that is processed by the simulation program, the simulation program being provided for calculating a virtual sensor system from the extended process image (c-PA erw_i, c-PAA erw_i, c-PAE erw_i), - wherein the operating system of the programmable logic controller is provided for managing the memory, - wherein the virtual sensor system is used to extend the process image (PA Anlage, PAA Anlage, PAE Anlage) to a process image (PA Anlage, PAA Anlage, PAE Anlage) that has been extended by the virtual sensor system, to such an extent as if sensor values calculated by the simulation program were determined by sensors of the installation, and wherein the process image (PA Anlage, PAA Anlage, PAE Anlage) extended by the virtual sensor system is provided for controlling the installation by the programmable logic controller. - wherein the programmable logic controller has a process image (PA Anlage, PAA Anlage, PAE Anlage) of the installation, the process image (PA Anlage, PAA Anlage, PAE Anlage) consisting of a process input image and a process output image, the process input image being transferred from the installation to the programmable logic controller and containing determined sensor data and/or positions of actuators that are readable by means of sensors and/or measured operating variables of electric machines of the installation, and the process output image being transferred from the programmable logic controller to the installation and containing commands for positioning actuators and/or commands for activating sensors, - wherein an extended process image (c-PA erw_i, c-PAA erw_i, c-PAE erw_i) has at least one copy of the process image (PA Anlage, PAA Anlage, PAE Anlage), - wherein the memory is provided for storing the extended process image (c-PA erw_i, c-PAA erw_i, c-PAE erw_i) and the process image (PA Anlage, PAA Anlage, PAE Anlage), - wherein the extended process image (c-PA erw_i, c-PAA erw_i, c-PAE erw_i) is provided for the simulation program, the extended process image (c-PA erw_i, c-PAA erw_i, c-PAE erw_i) being available in a data format that is processed by the simulation program, the simulation program being provided for calculating a virtual sensor system from the extended process image (c-PA erw_i, c-PAA erw_i, c-PAE erw_i), - wherein the operating system of the programmable logic controller is provided for managing the memory, - wherein the virtual sensor system is used to extend the process image (PA Anlage, PAA Anlage, PAE Anlage) to a process image (PA Anlage, PAA Anlage, PAE Anlage) that has been extended by the virtual sensor system, to such an extent as if sensor values calculated by the simulation program were determined by sensors of the installation, and wherein the process image (PA Anlage, PAA Anlage, PAE Anlage) extended by the virtual sensor system is provided for controlling the installation by the programmable logic controller.