Find where a tag is written in a Logix project

“What sets this output?” is the most common question on a project you did not write. In a large Logix project the tag may be written in several programs, inside an Add-On Instruction, or through an alias.

Ask it directly

Open the project in Orbis and ask the agent, for example:

Where is P_101.Req set?

The agent reads the project with Orbis tools and answers with the rungs where the tag is written. In the sample project on the home page, the answer to a question like this shows the agent tracing the writers of a tag and reading the tag it depends on, then drawing the rung.

Check the answer

Each cited rung opens in the editor. You can read it as ladder and confirm the agent found the writer you were looking for before you act on it.

Then change it, if you need to

If the fix is a logic change, ask the agent for it. It edits a working copy, and you review the change as ladder before exporting it. See Review changes.

Related: Ask the agent, Open a project.