Free AutoCAD symbols for DCS and shared display (DWG), ISA 5.3 style

About ISA 5.3 and ISA 5.1

ISA 5.3-1983, Graphic Symbols for Distributed Control/Shared Display Instrumentation, Logic and Computer Systems, was written for control systems with microprocessors and shared displays. Its content has since been merged into ISA 5.1-2009, which no longer exists as a separate document, but drawings, specifications and engineers still refer to ISA 5.3. This library follows the figures and the grouping of ISA 5.3. For discrete instruments, valves, primary elements and signal lines see the ISA 5.1 library, and use the two together.

These symbols are our own drawings after the figures of the standard. They are not copied from it, and the library is not certified against it. Company and project standards often differ in details such as the bubble size; change a block if your legend differs.

Frequently asked questions

ISA 5.3 was merged into ISA 5.1. Why a separate library?

Because people still look for it by that name, and many existing drawings and specifications are written to ISA 5.3. The library collects its symbols and example loops in one file, named the way you search for them. The same shapes appear in the ISA 5.1 library as the shared, computer and logic bubbles.

How is this library different from the ISA 5.1 library?

The ISA 5.1 library is the broad one: instrument bubbles for every location, primary elements, signal lines, valves and actuators. This library is focused on distributed control and adds what ISA 5.3 shows beyond the bubbles: computation blocks, system links, software alarm marks and the complete example loops. The devices needed to finish a loop are included here too.

Can I use the symbols in commercial projects?

Yes. They are free to use and modify in your own projects, including commercial ones. They are provided as is, without warranty.

Can I use the symbols in commercial projects?

Yes. They are free to use and modify in your own projects, including commercial ones. They are provided as is, without warranty.

Can I change a symbol or add attributes?

Yes. Open the DWG, edit a block with BEDIT to change it or add attributes, and save. To update drawings that already contain the block, run ATTSYNC or replace the block. Make a backup first: attribute values can be lost if ATTSYNC is used carelessly.

Where do I find a ready-made set of these symbols for AutoCAD?

AutoCAD itself ships only a small set of sample blocks, so a full symbol set has to come from a library. Download the ZIP on this page and open the DWG: every symbol is a block. Insert one with INSERT (Blocks palette, Libraries tab, then pick the DWG) or drag it from DesignCenter (ADCENTER). You can also download a single symbol on its own.