AutoCAD P&ID

[#1]

We are in the process of setting up a new project with naming guidlines for lines/valves/etc and have a question regarding the autogenerate expression function.

Here is our problem:

Our line tags are made up by four subparts: size service-system-line number. The issue is that our line number needs to refer back to both the system and service the precede it before autogenerating the line number.

For example, 12" HPS-01-001

12"- Line size

HPS-  Line Service

01- System line is being used on

001- Specific line number

The 001 means that this is the first HPS line being used on system 01. Then next line number in this sequence would be 002, 003, etc. If the System or Service changes, the last three characters (line number) would be start over at 001, depending on the System/Service combination.

Example:

10" FW-02-001 First FW line for system 02

6" FW-03-001 First FW line for system 03

4" BD-02-001 First BD line for system 02

Is there a way to use the autogenerate expression options while creating custom tags that will get the autogenerated number to look at both the Service and System before it in order to generate a number that is specific to those 2 qualifiers?

Thanks in advance for any feedback!