If I read this correctly, this might reference, for example, the input status of the P&ID equipment AA_TK01_LS01 (Area AA, Tank 01, Level Switch 01)?
If that's the case, what about all of your other tags associated with that device?
For example for a digital switch:
- on/off debounce timer setpoints
- alarm timer setpoint
- alarm reset command
I see this type of tag structure as being troublesome for use with templates, addition of functionality, and for general maintainability of the system. Also, what happens if the IO block suddenly needs upgrading, maybe they go from a DO_8 to a DO_16, or the IO block changes to a different rack? all of your tag references will need to change with it. In my opinion, you're far better off abstracting your tags away from their inputs and associating them with something fixed and that has a connection with the process to which they belong (e.g. a P&ID equipment ID)