CDL-PLC translator: From Modelica HVAC control design to IEC 61131 PLC implementation

Abstract

This paper presents the CDL-PLC translator, a tool toconvert control sequences for building heating,ventilation, and air conditioning (HVAC) systems expressedin a subset of Modelica called Control Description Language(CDL) which is undergoing standardization via the voluntaryASHRAE Standard 231P into the IEC 61131-10 XML format. Sucha translation is a step in a model-based design workflowand contributes to digitalizing the control deliveryprocess in the building sector. The translation into theIEC 61131-10 XML is the last step in the implementation ofcontrol logic developed in CDL on programmable logiccontrollers (PLCs) standardized in IEC 61131. The paperpresents the details of the translator, an example for thevalidation of a CDL block vs. the corresponding IEC block,and a practical application example for the translation ofa control sequence for a hybrid heat pump plant from a casestudy neighborhood in Belgium. Practical applications, usecases, and future developments are discussed in the contextof building industry processes.