In the programming of PLC-Systems (PLC = Programmable Logic Controller) in building automation there were no vital changes over the past few years. Most users of PLC-Systems in building automation do the programming in FBD (functional block diagram). The users always start their projects with the
programming of the PLC software. After that the HMI (Human Machine
Interface) or the SCADA-System (Supervisory Control And Data Acquisition)
are added as subsequent Tasks. Programming tools like CoDeSys build on this bottom up approach. Most of the time the user has to cope with different tools for the different tasks and the programming tools are built for a specific
hardware. Almost every PLC manufacturer has its own implementation of the
IEC 61131 standard with various interpretations. So a change of hardware
means that the programming tool, the way how to program the PLC-System, the HMI tool and the SCADA tool changes. The interfaces between the tools are sometimes pretty clumsy and software, generated with these tools, is often not easily transferred to the PLC-System of another PLC-System manufacturer.
This investigation proposes a top down approach to a project. For the first time the starting point of a project will be the plant diagram. The programming will be intuitively done in the plant diagram. Template objects (e.g. for pumps) created with the object orientated paradigm will be used to accomplish this task. The created PLC software will run in a virtual machine on the PLC-System and thus will be reusable on PLC-Systems of different manufacturers, which will eliminate the dependency on certain hardware.
The merging together of SCADA, HMI development and PLC programming will
lead to a more natural way in programming PLC-Systems. In a first step the
user draws his plant diagram with template objects (TO) and afterwards binds
the template objects on the plant diagram together. With this approach the user only has to cope with a single software tool. The independency from the PLC hardware will be an additional alleviation for the user.
The aim of the investigation is to determine the realisability of a generic
SCADA-System FBD programming language, a virtual machine and a code
generator for PLC-Systems
