【正文】 , systemneutral model [1]. This model is developed with an extension of the formal description language UML (UML: Unified Modeling Language) that was adapted to the special requirements of control engineering. By the use of UML a modular and structured model developing is guaranteed. To support accelerated and transparent engineering processes standardized and reusable software ponents are used. The concept of UMLbased PLC software generation was implemented using an elementary example of screening plant with 28 sensors and 19 actors. With a special developed software translator the UML model is translated to IEC 611313 conform PLC software code. Afterwards this code is imported as Structured Text (ST) in the PLC programming tool CoDeSys [1]. . Automated PLC software generation based on Petri Nets In [2] and [3] a concept for automated PLC software generation based on Signal Interpreted Petri Nets(SIPN) is presented. The basic idea is similar to the UMLapproach from the research project DisPa. Analog to the formal description language UML, SIPN allows a transparent graphical description of process oriented control algorithms. With special software translators these SIPN can be translated in executable IL code (IL: Instruction List). For prototypical applicability a demonstrator was developed that creates IL code from SIPN related to PLC open standard based on the program Mathematica. Thus, SIPN not only are specification tools but also they can be used as adequate PLC programming language [2]. One important advantage of SIPN towards the programming languages defined in IEC 611313 are SIPNspecific algorithms that analysis automatically the transparency and correctness of the programs [3]. . VR based PLC software generation related to Osmers The dissertation from Osmers [4] focuses the improvement of PLC projecting with the aid of techniques from Virtual Reality (VR). During the planning process the manufacturing cell is configured in a virtual environment. The PLC programming takes place the same model. This is done in a graphical, interactive way. Base for the automated generation of PLC code are the electrical resources (sensors, actuators). These objects are embedded as 3Dgraphics in the cell model. In a next step these single objects are logical connected with Boolean operators by the use of preconfigured interactions with user (visual programming). With the aid of a special developed, proprietary ILpiler these information are converted from the virtual reality tool in machinereadable form. Then the generated PLC code is downloaded in a PLC programming tool. The software specific transfer of the concept developed by Osmers was acplished with the virtual reality tool VRT (Superscape LTD) and the PLC programming tool STEP 7 (Siemens). . BMBF project MODALE Focus of the BMBFproject MODALE (MODALE: Modellbasiertes Anlagenengineering) is the panywide data exchange between different departments that are involved in the planning process of an automated manufacturing cell [5]. For this, an ontologybased reference model is developed that – embedded in a technical infrastructure – acts as central data dial. Based on these technical conditions data from digital planning tools are exported and transferred to the ontologybased reference model with the help of semantic bridges. There a data transformation takes place and the generated data are imported in the respective target application [6]. So it is possible to exchange digital planning information between different IT tools without loosing important information. The prototypic transfer of this IT infrastructure and the verification of the principally operability was demonstrated using elementary examples. One practical scenario focuses the automated generation of a PLC Sequential Function Chart related to IEC 611313. Base model is a digital process plan that is developed in the production planning and enhanced with PLC specific information (. transitions) [7]. This model is exported with a special developed RDFinterface (RDF: Resource Description Framework), transformed with the aid of the reference model and finally imported in the target system in form of a SFC. The developing of the digital process plan is done with the digital process planning tool DELMIA Process Engineer (DPE) from the pany DELMIA. The used PLC programming tool is Open PCS, developed and distributed by the pany info team. . PLC software generation with Process Simulate Commissioning In contrast to the presented approaches in preceded sections the IT tool Process Simulate Commissioning represents a mercial software tool that was developed in 2020 by a cooperation of Teomatics and Siemens. Base for the automated PLC software generation is a digital 3D cell model and the digital process description of this cell. Analog to the developed approach in the project MODALE, the digital process description is enhanced with control technical information, . I/Osignals. The enhancement takes place either by manual adding of necessary parameters or by connecting of resources (clamps, valves, robots etc.) with the corresponding operations in the digital process model [8]. With this enhanced process model and a software translator developed by Siemens an executable PLC program for the PLC programming tool STEP 7 can be generated. So the generated program contains all relevant I/Osignals in the symbol table as well as a SFC that describes the process flow in S7 Graph. . Evaluation In the previous sections different approaches for the automated PLC software generation were presented. These approaches base on different assumptions, methodologies and IT tools. Regarding a potential use in the planning process of manufacturing cells, all these approaches have their specific advantages and disadvantages which are pared in table 1. C