ACD vs L5X: the two Studio 5000 files you'll be sent
Studio 5000 projects travel in two main shapes: the .ACD the engineer works in, and the .L5X they export. They hold almost the same logic, but they behave very differently when you try to open them.
.ACD is Logix Designer's native binary project file, opened only by the same major version of Studio 5000 or newer. .L5X is an XML export of a project or a component, readable by any XML tool and importable by Studio 5000, including older versions when the project uses nothing newer. .L5K is the older plain-text export. For archiving and handing projects between versions or tools, L5X is the safer format; for day-to-day work, engineers keep the .ACD.
.ACD: the working project
The .ACD is what Logix Designer opens and saves. It is a binary database holding the full project and some extras: online edit history, trend definitions, and the uploaded tag values from the last time someone went online. It is compact and fast, but undocumented and tied to the major revision of Studio 5000 that last saved it.
.L5X: the XML export
File › Save As › L5X writes the same project as XML. Every rung appears as "neutral text", for example XIC(Start_PB)XIO(Stop_PB)OTE(Motor_Run);, inside a structure of programs, routines, tags and data types. You can also export a single routine, rung, AOI or UDT as L5X and import it into another project.
Because it is text, an L5X can be diffed in Git, searched with any editor, and processed by scripts. It is also how most free viewers read projects.
.L5K: the older text export
L5K is the plain-text export inherited from RSLogix 5000. It carries the same information in a bracketed text syntax. You will still meet it on older projects and in some migration tools, but new work mostly uses L5X.
Which one to ask for
- You need to read the logic: either works in Rungview. An L5X opens on the free plan; an .ACD opens on Pro.
- You need to import it into an older Studio 5000: ask for L5X. An .ACD from a newer version simply won't open.
- You need to edit and download: the .ACD, opened in the matching Studio 5000 version.
- You want version control: commit the L5X alongside the .ACD so changes show up as readable diffs.
Open either file in one app
L5X opens free with no limit. .ACD files open on Pro, from $9 a month.
Get Rungview
.ACD and .L5X · read-only, never touches the PLC · files stay on your computer · cancel Pro any time.
FAQ
Does an L5X contain everything the ACD does?
All the logic, tags, data types, AOIs and module configuration, yes. Some project extras, such as trends and online edit history, may not carry over.
Can I turn an ACD into an L5X without Studio 5000?
Yes. Rungview Pro exports an .ACD as .L5X on your own computer.
Is an L5X smaller than an ACD?
Usually larger, because XML is verbose. It compresses very well in a ZIP.