Instrument Loops in AutoCAD P&ID


After one of the craziest summers I have seen since I have been on this job, I finally got a chance last week to get back into setting up my AutoCAD P&ID software.  It took a little while just to remember where I had left off, but before long I was making progress again toward getting things set up to our company standards.

In my test project, I ran into one particularly challenging operation.  One that should have been relatively easy.  I wanted to create a simple instrument loop where, after placing a primary instrument on a line, all related instruments connected to it took on the same instrument loop number.


This turned out to be more of a challenge than I thought it should be.  None of the signal lines, or general instrument symbols contained any of the necessary acquisition rules to make this happen.  I searched the internet, including the Autodesk Community forum for AutoCAD P&ID.  There was no easy workflow described, and in fact several of the posts I read said that this is something that can be fairly difficult to achieve.

I don’t like to be told that my software can’t do something I need it to do.  I take it as a personal challenge, as I did this past week.  I did find a video that showed the steps needed for these rules, but the forum thread I found it in went on to report that it no longer worked.  So, I used this as a starting point and did some trial and error testing with rules and custom properties.  After a few hours, I finally managed to put together a workflow that gave me what I was looking for.  As with all of my tips, I will say that this may not be the best, or even the only way to do this.

Rather than try to describe each individual step here, I have recorded a short video of the steps I used too to accomplish this.  Note that the property names can be whatever you want them to be, but they should not be the same from one class to another.  Also, I suggest writing the names down so you can easily remember them when moving back and forth between class definitions. So, without further ado, here is the video.

In the video, I neglected to mention that I also created a couple of new Tag Formats.  The first was created under Inline Instruments, as shown here:


The next was under General Instrument Symbols, as so:


I set these both to the default for these classes by setting TagFormatName:


With all of these pieces in place the workflow performed as I hoped it would.  One more hurdle passed.  I hope this helps you at least in some small way.  Thank you and as always…


“Autodesk ® screen shots reprinted with the permission of Autodesk, Inc.  Autodesk ® , AutoCAD® , DWG, the DWG logo, Vault ®, Autocad Electrical ® and Inventor ® are registered trademarks or trademarks of Autodesk, Inc., and/or its subsidiaries and/or affiliates in the USA and other countries.”  Programs and programmers’ information used with permission.  Thanks guys!



CAD Department Supervisor at Powell Fabrication & Manufacturing, Inc. CAD Designer & Detailer specializing in Inventor Tube & Pipe, Frame Generator, Content Center, Vault Professional. Autodesk Expert Elite member. Blogger. AU 2014 Speaker. Husband and father.

Tagged with:
Posted in AutoCAD P&ID, General, Show All

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Post Archive
Follow me on Twitter
photographingGOD Photography

You Will Never See Life The Same Way Again!

Lightscapes Nature Photography Blog

Kerry Mark Leibowitz's musings on the wonderful world of nature photography


Providing the CAD knowledge you need to succeed.

The CAD Setter Out

AutoCAD and Inventor Tips, Tricks & Tutorials.

Design & Motion

Design and Manufacturing solutions through Digital Prototyping and Interoperability

Dedicated to the Autodesk Inventor Community

%d bloggers like this: