@tpro4391/node-red-tienho-mewtocol-panasonic 1.0.0
Panasonic PLC MEWTOCOL-COM over TCP for Node-RED: shared queued connection, read and write nodes (FP-X, FP0H, FP7, ...)
@tpro4391/node-red-tienho-mewtocol-panasonic
Panasonic PLC MEWTOCOL-COM over TCP for Node-RED (FP-X / FP-XH / FP0H / FP7 / FP-Sigma with ET-LAN, or any serial-to-Ethernet converter in front of a MEWTOCOL port).
Reference: Panasonic MEWTOCOL manual
What's new in 1.0
- One shared, persistent TCP connection per PLC with a FIFO command queue (0.0.x opened a new socket for every message).
- Auto reconnect with back-off, fail-fast while the PLC is offline, bounded queue.
- Robust frame handling: CR-delimited stream parser, multi-frame responses, real BCC generation and verification.
- Large ranges are split automatically so every command fits a single frame (
%118 chars or<2048 chars). - Write nodes: WD, WCC, WCS, WS, WK. New read node: RCP. Raw command node.
- Data types:
int16,uint16,int32,uint32,float32,hex,bits,string. - Bug fixes: RS / RK sent the RR command, address
0frommsgwas ignored, crashes when the config node was missing, ... - No runtime dependencies (the
jsmewtocoldependency is replaced by the built-inlib/). - Backwards compatible: node types, properties and output format of 0.0.12 flows are unchanged.
See CHANGELOG.md for the full list.
Install
In your Node-RED user directory (usually ~/.node-red):
npm install @tpro4391/node-red-tienho-mewtocol-panasonic
or use Menu → Manage palette → Install and search for tienho-mewtocol. Restart Node-RED afterwards.
This package is a reworked fork of node-red-contrib-mewtocol and uses the same node types (
mewtocol-rd, ...), so existing flows keep working. Uninstallnode-red-contrib-mewtocolfirst – both packages cannot be installed at the same time.
Requires Node-RED ≥ 2.0 and Node.js ≥ 14.
Nodes
| Node | Command | Description |
|---|---|---|
| RD | RD |
Read data registers DT (D), link registers LD (L), file registers FL (F) |
| RCC | RCC |
Read contact words X, Y, R, L |
| RCS | RCS |
Read one contact bit X, Y, R, L, T, C |
| RCP | RCP |
Read a list of contact bits, e.g. X0, Y1A, R100F, T5 (auto split per 8) |
| RS | RS |
Read timer/counter set values |
| RK | RK |
Read timer/counter elapsed values |
| RR | RR |
Read system registers |
| RT | RT |
Read PLC status (type, version, RUN/PROG, error flags) |
| WD | WD |
Write data / link / file registers |
| WCC | WCC |
Write contact words Y, R, L |
| WCS | WCS |
Write one contact bit Y, R, L |
| WS | WS |
Write timer/counter set values |
| WK | WK |
Write timer/counter elapsed values |
| RAW | any | Send any command body, e.g. RDD0000000009 |
Every node has two outputs: 1 = result, 2 = error.
Message properties
msg.station, msg.area, msg.startaddress, msg.endaddress, msg.address, msg.addresses, msg.datatype
override the node settings (0 is a valid value). All other message properties are kept.
Read nodes put the data in msg.payload – a single value or an array (enable Always output an array to always get an array).
Write nodes take the data from msg.payload and pass the message on unchanged after the PLC acknowledged it.
Every result also carries msg.mewtocol (command, station, area, start, end, ...).
The error output receives a copy of the input message with msg.error (text), msg.errorCode
(EPARAM, EPLC, ETIMEDOUT, ECONN, EBCC, EPROTO, EQUEUEFULL, ECLOSED, ECONFIG) and,
for errors returned by the PLC, msg.plcErrorCode (e.g. 61 = data error, 66 = address error). Errors are also
reported to Catch nodes.
Addresses
- Registers / words: decimal word number (
DT100→ areaD, address100). - Contact bits (X, Y, R, L): word + hexadecimal bit, e.g.
100A= R100A (word 100, bit 10),1F,5. - Timer / counter contacts (T, C): timer/counter number.
- 32-bit types use two consecutive words, low word first (Panasonic
DDTorder).
Connection settings
| Setting | Default | |
|---|---|---|
| Host / Port | – / 9094 | PLC address |
| Timeout | 5000 ms | connect and response timeout |
| Frame | Standard % |
Extended < = 2048 chars per frame, fewer round trips (FP-X, FP0R, FP7 ...) |
| BCC | on | compute and verify the block check code |
| Keep connection open | on | persistent socket + auto reconnect; off = close when idle |
| Max queue | 100 | waiting commands before EQUEUEFULL |
Using the library without Node-RED
const MewtocolClient = require('@tpro4391/node-red-tienho-mewtocol-panasonic');
const plc = new MewtocolClient({ host: '192.168.1.5', port: 9094, timeout: 3000 });
const words = await plc.readWords('RD', 1, 'D', 0, 9); // raw uint16 words
await plc.writeWords('WD', 1, 'D', 100, [1, 2, 3]);
await plc.writeBit(1, 'R', '10', true);
const bits = await plc.readBits(1, ['X0', 'Y1A', 'R100F']);
const status = await plc.readStatus(1);
await plc.close();
The jsmewtocol style API (new MewtocolClient(host, port, timeout), RD, RCS, RCC, RS, RK, RR, RT, destroy) is also available.
Tests
npm install
npm test
The tests run against a built-in PLC simulator (test/mock-plc.js) including TCP fragmentation,
multi-frame responses, BCC errors, timeouts, dropped connections and a PLC that accepts only one socket.
License
See LICENSE. Based on node-red-contrib-mewtocol © Oleg Aroslanov (oleg31337), used under its MIT-style license with attribution. Version 1.0 rework by Tpro4391.
