Cleaning and Pretreatment Machinery Information Model overview – OPC UA for Surface Technology

6 Cleaning and Pretreatment Machinery Information Model overview

This section provides an overview of the OPC UA information model for cleaning and pretreatment machinery.

The information model is based on and extends the Companion Specification for Surface Technology (ST) - General Types (STGeneral), which is structured to represent the physical machine and its system components in a modular way. This is necessary due to the complex and varied nature of cleaning and pretreatment machinery, that was described in Section 4.1, allowing for a large variety in machine construction and configuration.

The approach of STGeneral is to model a cleaning and pretreatment machine as a collection of different systems, representing different zones or functionalities of the overall machine (e.g. cleaning zone, rinsing zone, handling system etc.).

A visual example of a machine layout is depicted in Figure 6. Each one of these systems is modelled as a machine in accordance with OPC UA for Machinery and can contain additional components of 3:MachineComponentsType, which serve to model the structure and location of sensors in single systems in more detail (e.g. multiple heating elements, pumps and a tank or vessel within a cleaning zone).

Figure 6 - Illustration of the modelling logic using STGeneral and STCleaningPretreatment

The different Systems of a cleaning and pretreatment machine can be modelled as Subtypes of the abstract 9:STSysType inherited from STGeneral. On its first level, it contains folders for 3:MachineryBuildingBlocks as well as AddIns for Monitoring and Components. Each system can be identified, and relevant process parameters can be monitored either on the system or on the component level.

The structure of the overall cleaning and pretreatment machine can be modelled using the 0:IsPhysicallyConnectedTo and 0:Controls references (e.g. to describe a specific sequence of zones or systems within a machine).

The AddIn Components contains the sub-components of a specific System. Components are Subtypes of the abstract 9:STCompType inherited from STGeneral. The Structure of 9:STCompType is similar to 9:STSysType but does not contain additional sub-components and is primarily used to identify and describe components and to monitor specific process parameters on the component level.