Let’s look at a possible asset model for a rack into which controllers, power supplies and I/O modules are inserted. The rack may be cabled to an extension rack, where the extension rack holds additional I/O modules. The rack is illustrated in Figure D.8.
This main rack could be modelled in a number of manners. Figure D.9 illustrates one possibility. The figure is not complete in that not all subcomponents or details are included. The model has a base rack model (MyRackType) that can represent any rack, including the Subunit. The base rack does include redundant power supplies. The main unit is modelled (MyMainRackType) as a subtype of this rack. The main unit includes a CPU, which is mandatory and always sits in Slot1.
Figure D.10 illustrates the model for the CPU module. This model is based on interfaces and includes software update functionality. It also provides a variable that represents the temperature of the CPU (and the engineering units associated with the temperature). The CPU model also provides an enumeration that represents the status of the CPU module (Failed, Degraded, Normal). This status is used as an indicator light on the module.
Figure D.11 illustrates the IO Module model. This IOModuleType is a subtype of FxAssetType. The model includes a StatusIndicator that behaves exactly the same as the CPU Model StatusIndicator (Figure D.10). The model also supports software updates. The model includes a folder for connectors, where the connector provides connections to external IO. These connectors may be of any type depending on the type of connected IO device. It is expected to be further subtyped. This model reflects specific types of external IO connections and devices.
Figure D.12 illustrates the power supply module. This model is just a base object that exposes the required interfaces. The PowerSupplyType has a reduced set of IVendorNameplate properties. PowerSupplyType provides a Variable that reflects the power output of the supply. PowerSupplyType also has a variable that reflects the temperature. PowerSupplyType, as with all of the modules, includes a status indicator.
Figure D.13 provides an illustration of a deployment of this model. The instance provides an additional CPU and includes several IO modules. The figure also illustrates the values of some of the variables in the various models. The figure omits many variables and values for simplicity. These variables would exist in the actual complete model. The model does not describe the devices that are connected to the IOP modules. This model is used for additional examples.