CMsoft Import for PAC Machine Edition

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Import Emerson PAC Machine Edition projects into VS Code as PLCopen XML and Structured Text, edit them and export them back to PME - with Copilot tools, a chat assistant and an MCP server.

Work on your PAC Machine Edition (PME) PLC projects from Visual Studio Code: import the logic blocks, data types, variables, hardware configuration and EGD of a PACSystems target into the workspace, edit them with the tools you like — Copilot included —, export them back to PME, compile the target and read the results in the Problems panel. Or let an AI agent do the round trip through the built-in Language Model tools and MCP server.

Requirements: Windows 10 or 11 and PAC Machine Edition (Emerson) installed and licensed — tested with version 10.7. The extension drives PME through its automation interface and does not replace it. Nothing else: no Node.js, npm or build tools — the extension comes ready to run.

How it works with PAC Machine Edition

• Connect first asks which project to open — the Windows file dialog opens in your PME project store — and then starts PAC Machine Edition hidden and opens it. Close PME before you connect: its automation interface works only while no other PAC Machine Edition window is open — the extension tells you when one is. There is one connection at a time: while one VS Code window is connected, PME is not available to another one.
• Before the first export to PME of a session the extension writes a ZIP backup of the project into the backup folder of PME; every successful export is saved in the project (PME also saves the project before it compiles a target or backs the project up). Disconnect closes the hidden PME again.
• Closing VS Code (or Reload Window) while connected closes PME as well: the extension's background process quits it within about half a minute after the window is gone (the exports are saved already). A window that connects meanwhile waits until it has closed.
• Open Project in PAC Machine Edition hands the project over to you in a normal PME window — for example to download it to the controller — and ends the session.
• Projects the extension opens do not change the Recent Projects list of PME.

Features

FREE plan limits — the same as in CMsoft Import for TiaPortal: one operation (one command such as importing an item, a target or the whole project, or exporting a file or a target folder) moves at most 10 objects in either direction — a block, a data type, the variable list, the hardware configuration and EGD count one each —, and the next import or export is available 15 minutes after the previous one has ended, in every VS Code window and after a restart. An operation over the limit is refused before anything is read or changed, and the dialog says what the limit is and when the next operation is possible. PRO and the free trial have no limits.

PRO comes as a monthly or yearly subscription per seat, with a free trial — see CMsoft Import for PAC Machine Edition: Manage License / Subscription and the shared CMsoft item in the status bar.

Getting started

1. Close PAC Machine Edition and open a folder in VS Code (the projects are imported into <folder>/PmeImport/).
2. Open the CMsoft Import for PAC Machine Edition view in the activity bar, click Connect and pick the .SwxCF file of the project in the dialog (it opens in the PME project store).
3. In the Project view, import a target (or a single block) into the workspace.
4. Edit the .st file of a Structured Text block (or another imported file) and right-click it → Export File to PME — or right-click the target → Export Target Folder to PME —, then Compile Target (Validate) — the icon in the title bar of the editor, or right-click the file or the target — and read the Problems panel.
5. Disconnect when you are done, or Open Project in PAC Machine Edition to continue in PME.

No PME at hand? Turn on emersonImport.demoMode and connect to a simulated project.

Files in the workspace

PmeImport/<project>/<target>/
  Logic/<block>.xml        every Ladder and Structured Text block as PLCopen XML, as PME exports it - indented
  Logic/<block>.st         the Structured Text of an ST block - edit this file, the export puts it into the block
  Data Types/<type>.xml    user defined data types (PLCopen XML, indented)
  Variables.xml            the variable list (indented)
  Hardware.xml             the hardware configuration (indented)
  EGD.zip, EGD.xml         Ethernet Global Data - the archive PME reads, and its XML to read

PME writes these XML files on one line; the extension indents them — one element per line — so you can read, compare and edit them. Nothing else changes: the export to PME removes the indentation again, and PME reads exactly the file it wrote (emersonImport.formatXml off keeps PME's one-line files). Importing a target again replaces these files and removes the files of blocks that no longer exist, so the folder can be kept under version control: unchanged blocks come out byte for byte the same. Ladder (LD) blocks are imported as XML. Not supported: Function Block Diagram (FBD) blocks and Sequential Function Charts (SFC — PME has them only for Windows PC and QuickPanel Control targets, not for PACSystems), and C blocks: PME exports no XML for them.

AI assistants

• Copilot / VS Code chat: the pme_* Language Model tools, or ask @pme. Exports to PME and the hand-over to PME ask for confirmation unless emersonImport.lmTools.autoConfirmExports is on.
• MCP clients (Claude Code, Claude Desktop, other agents): the extension runs a localhost MCP server (Streamable HTTP, emersonImport.mcp.enabled, on by default). The endpoint and its Bearer token are written to .pme/mcp.json. VS Code 1.99+ discovers it by itself. MCP clients act without confirmation dialogs.
• Scripts (PRO): the opt-in CLI bridge (emersonImport.cli.enabled), endpoint and token in .pme/cli.json — see below.
• Prepare Workspace (PRO) puts the instructions for AI agents into the workspace: .github/instructions/emerson-import.instructions.md (Copilot applies it to every file), emerson-import-cli.instructions.md, Tools/pme_cli_example.py, and a section of this extension in AGENTS.md, CLAUDE.md, .github/copilot-instructions.md, .gitignore and Tools/README.md — next to the sections of the other CMsoft extensions; your own text stays.

The CLI bridge is plain HTTP, so any language works — PowerShell needs nothing else installed:

$s = Get-Content .pme/cli.json | ConvertFrom-Json
$h = @{ Authorization = "Bearer $($s.token)" }
Invoke-RestMethod -Method Post -Uri "http://$($s.host):$($s.port)/api" -Headers $h -ContentType 'application/json' `
                  -Body '{"command":"current_project","args":{}}'

The extension also ships a command-line helper, which runs on the runtime built into VS Code — no Node.js needed. Put this function into your PowerShell profile (notepad $PROFILE) and call it from the workspace folder:

function emerson-import {
    $cli = Get-ChildItem "$env:USERPROFILE\.vscode\extensions\MariuszCzyrnek.emerson-import-*\scripts\emerson-import-cli.js" |
           Sort-Object LastWriteTime | Select-Object -Last 1
    $code = Join-Path (Split-Path (Split-Path (Get-Command code).Source)) 'Code.exe'
    $env:ELECTRON_RUN_AS_NODE = '1'   # Code.exe works as Node.js while this is set
    try { & $code $cli.FullName @args | ForEach-Object { $_ } }   # the pipe makes PowerShell wait for the answer
    finally { Remove-Item Env:ELECTRON_RUN_AS_NODE }
}

emerson-import current_project --pretty

If VS Code was installed without Add to PATH, write the full path of Code.exe into $code (for an installation for the current user "$env:LOCALAPPDATA\Programs\Microsoft VS Code\Code.exe").

AI-generated changes are your responsibility: review and test them before they reach a real machine.

Settings

Troubleshooting

To go back to an earlier state of a project, open one of the backups in the backup folder of PME with Open Project File or Backup — a restore never overwrites a project, so rename or delete the project in PME first.

Support

Questions, problem reports and ideas go to the issue tracker of the public documentation repository EmersonImport.VSExt — it also holds this README, the changelog, the license documents, the user manual and the instructions for AI assistants of every release. An issue is public: do not attach projects, logs that name your projects or license keys — send them, and security problems (SECURITY.md), by e-mail to office@cmsoft.com.pl.

Privacy and licensing

The extension sends no telemetry and no project data; it works locally with PAC Machine Edition. What the license functions send, and when, is described in the Privacy Policy (PRIVACY.md); the license terms are in the End User License Agreement (LICENSE.md), the terms of sale in TERMS.md. The three ship with the extension and the license panel opens them; how to report a vulnerability is in SECURITY.md in the extension folder.

PAC Machine Edition and PACSystems are trademarks of Emerson or its affiliates. This extension is not affiliated with or endorsed by Emerson.