There are two types of instruments that you can define and place in the software.
Catalog instruments are similar to piping components. The selection of catalog instruments is driven by the Requisition Type, not by the tag number in Tag Number or Generic Tag Number. You define a tag number in the Instrument Class Data. You can then:
Define a commodity code and add that commodity code to Piping Commodity Material Control Data, just as you would a piping component. In this case the Requisition Type should be set to 5.
Not define a commodity code, but define in the Instrument Class Data all the properties such as the Short Material Description, Fabrication Type, Gasket Requirements, and Welding Requirements. In this case the Requisition Type should be set to 10.
Define the instrument parts in part classes.
Custom instruments are not defined in the Instrument Class Data and are either:
Read in from SmartPlant Instrumentation (INtools) from the SmartPlant integrated environment. The transfer is either based on the SmartPlant Instrumentation Group with each Group equal to a dummy part class name, or is defined completely by you in the model. The symbols are designed to communicate with the routing engine to drive the properties of the connection port to the instrument port.
You relate the part classes to the Custom Instruments node and then you browse to the instrument.