Model-driven development of process-control software

Tekom celotne zgodovine razvoja programskega inženirstva ugotavljamo, da je v krizi in da je dejansko bolj podobno umetnosti kot inženirstvu. To velja za vse problemske domene, pri čemer domena vodenja procesov ni izjema. Veliko je bilo poskusov premagovanja krize programske opreme skozi iskanje ustreznih tehnologij (metod, orodij ali procesov). V zadnjem času se kot zelo perspektivna kažeta dva pristopa, in sicer uporaba visokonivojskih domensko-specifičnih abstrakcij (modelov) in ponovna uporaba znanja in artefaktov na visokem nivoju abstrakcije. Z združevanjem teh dveh pristopov pridemo do tistega, čemur danes rečemo domensko usmerjena generativna ponovna uporaba na osnovi modelov. Modelno usmerjene pristope k graditvi programske opreme delimo v dve konceptualno različni skupini, ki temeljita na dveh različnih filozofijah modeliranja. Prva skupina temelji na splošnonamenskem modeliranju (GPM) in na splošnonamenskih jezikih (katerih najbolj znani predstavnik je UML). Druga filozofija modeliranja temelji na domensko-specifičnem modeliranju (DSM) in domensko specifičnih modelirnih jezikih (DSML), kjer kot model smatramo visokonivojsko, domensko-specifično abstrakcijo, to je abstrakcijo, v kateri nastopajo relevantne entitete iz problemske domene. Med obema pristopoma je prišlo do tekmovanja, pri čemer lahko ugotovimo, da vsak izmed njiju ima tako prednosti kot pomanjkljivosti. V zadnjem času kaže, da se tehtnica nagiba proti domenski usmerjenosti in generativni ponovni uporabi, kar je skladno tudi z našim stališčem. Jedro dela predstavlja rezultate aktivnosti domenskega inženirstva za izbrano domeno vodenja procesov. Najprej predstavimo model izbrane domene, to je entitete in njihove medsebojne relacije. V nadaljevanju predstavimo glavni dosežek tega dela, in sicer domensko specifični modelirni jezik ProcGraph. Sledi opis preslikave iz jezika ProcGraph v izvorno kodo jezikov ciljne platforme (industrijskih krmilnikov). Preslikavo določimo za dve ciljni platformi, in sicer Mitsubishi in Siemens. V nadaljevanju dela podamo ilustracijo modela v jeziku ProcGraph za realen projekt avtomatizacije srednje velikega industrijskega procesa. Na konkretnem primeru prikažemo in razložimo vse pomembne elemente jezika.Throughout the history of software engineering, it has been repeatedly stated that software engineering is in a crisis, and that it is an art rather than an engineering discipline. This is the case for all application domains, and the domain of process control is no exception. There have been many attempts to overcome the software crisis by applying appropriate technologies (methods, tools or processes). Recently, two promising approaches have emerged – the use of high-level domain-specific abstractions (models), and the reuse of knowledge and artefacts on a high level of abstraction. The merging of these two approaches leads to the modern concept of domain-oriented model-based generative reuse. Model-based approaches to software construction can be classified into two conceptually distinct groups, based on different modeling philosophies. The first group is grounded in general-purpose modeling (GPM) and general-purpose languages (with UML being the best known one). The second modeling philosophy is grounded in domain-specific modeling (DSM) and domain-specific modeling languages (DSML), with the model being regarded as a high-level, domain-specific abstraction, containing relevant problem domain entities. The two mentioned approaches are competing and they both have their advantages and their weaknesses. Recently, the latter approach has been prevailing, which is also our preference. The central part of the text presents the results of the domain-engineering activity for the selected domain of process control. First, the domain model is presented, consisting of the domain entities and their relations. Then, the new DSML ProcGraph is presented, which is the main contribution of this work, and the mapping of the ProcGraph models to the source code of the target platform (industrial controllers) languages. Two target platforms, Mitsubishi and Siemens, have been dealt with. In the following the ProcGraph model for a real, mid-size industrial project is presented as an illustration of the practical use of the language. All the important elements of the language are shown and explained for real cases