@fa_yoshinobu/node-red-contrib-plc-comm-slmp 5.2.0
Node-RED nodes for MELSEC PLC communication over SLMP binary 3E/4E frames.
Node-RED MELSEC SLMP Nodes
Node-RED nodes for MELSEC SLMP (Binary 3E/4E) PLC communication.
PLC Comm Family
This library is part of the plc-comm family. See the package matrix for protocol, language, registry, and install-command mapping.
Supported PLC profiles
The maintained profile table is in PLC profiles. Choose one exact canonical PLC profile from that table.
Profile enforcement
Every slmp-connection requires one concrete PLC profile. Operations known to be unavailable for that profile are rejected before sending; normal Node-RED flows do not expose a profile-enforcement bypass. Protocol investigation that needs raw PLC evidence belongs in the separate maintainer verification tooling.
Request serialization
Requests sent through the same slmp-connection are serialized in FIFO order on that client connection. A queued request is not sent until the previous request has completed, timed out, or failed. Closing rejects active and queued work and prevents the old queue generation from reconnecting. This applies to 3E/4E and TCP/UDP requests, including send-only requests.
If a flow needs real parallel PLC communication, create separate slmp-connection config nodes so each path uses its own PLC connection.
Supported device types
The maintained device and range tables are in the SLMP Profile Reference. Use that page for supported device families, address syntax, and profile-specific notes.
Installation
In the Node-RED editor:
- Open Manage palette.
- Open the Install tab.
- Search for
@fa_yoshinobu/node-red-contrib-plc-comm-slmp. - Install the package.
- Restart Node-RED if your environment requires it.
Quick start
- Open the Node-RED import dialog.
- Import
examples/flows/slmp-basic-read-write.json. - Open the
slmp-connectionconfig node. - Set Host to
192.168.250.100. - Set Port to
1025. - Set Transport to
TCP. - Set PLC profile to
melsec:iq-r. - Deploy the flow.
- Trigger the read inject node and check
msg.payloadin the debug sidebar.
The optional write button is only for controlled test addresses. It reads and saves the original values, writes random valid values, restores the snapshot after confirmed acknowledgements, and reads again. If any write or restore fails or has an unknown outcome, stop and reconcile the PLC values manually; the automatic sequence does not retry.
Start with the basic flow before importing the device-matrix flow.
Documentation
| Page | Use it for |
|---|---|
| Full documentation site | Unified docs for all PLC communication libraries. |
| Getting started | Install the nodes, configure a connection, and run your first SLMP read. |
| Usage guide | Use read/write nodes, routing fields, typed values, and flow patterns. |
| API reference | Find public client methods, helpers, profile APIs, and error types. |
| SLMP profile reference | Check profile parameters, device families, address syntax, and numbering rules. |
| PLC profiles | Choose the canonical MELSEC profile and frame behavior. |
| Gotchas | Check whether this library has any current library-specific caveats. |
| Performance | See measured latency, throughput, and long-run soak results from real PLC hardware. |
| Choosing a Language | Compare the .NET, Python, Rust, C++, and Node-RED implementations before you pick one. |
| Example flows | Import maintained Node-RED example flows. |
For a zero-code connectivity check, see PLC Scope (Windows).
License and registry
| Item | Value |
|---|---|
| License | MIT |
| Registry | npm |
| Package | @fa_yoshinobu/node-red-contrib-plc-comm-slmp |
Commercial support
If you plan to embed this library in a paid or commercial product, please consider a separate support agreement or supporting the project as a sponsor.
Contact: https://fa-labo.com/contact.html
