### Install Node.js 6.x using NodeSource

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Raspberry-PI2-and-PI3-hints

This command fetches and executes the NodeSource setup script for Node.js 6.x, preparing your system for installation.

```bash
curl -sL https://deb.nodesource.com/setup_6.x | sudo -E bash -
```

--------------------------------

### Troubleshooting npm Install

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/README.md

If you encounter issues during installation, try these npm install options to assist with building the package.

```bash
npm install --unsafe-perm --build-from-source
```

--------------------------------

### Install Node.js with NPM

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Raspberry-PI2-and-PI3-hints

Installs Node.js globally using NPM after setting up the NodeSource repository.

```bash
sudo npm install -g nodejs
```

--------------------------------

### Install Node-RED and Modbus Module

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Raspberry-PI

Install Node-RED, node-red-contrib-modbus, and node-red-node-data-generator globally using npm. The --unsafe-perm and --build-from-source flags are used during installation.

```bash
sudo npm install -g node-red --unsafe-perm --build-from-source
```

```bash
sudo npm install -g node-red-contrib-modbus --unsafe-perm --build-from-source
```

```bash
sudo npm install -g node-red-node-data-generator --unsafe-perm --build-from-source
```

--------------------------------

### Install node-red-contrib-modbus

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

Install the Modbus contribution package in Node-RED. Enable debug logging by setting the DEBUG environment variable.

```bash
# In the Node-RED installation directory
npm install node-red-contrib-modbus

# Global install
npm install -g node-red-contrib-modbus

# Enable debug logging
DEBUG=contribModbus*,modbus-serial node-red -v
```

--------------------------------

### Install Node-RED Modbus Globally

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/README.md

Install the node-red-contrib-modbus package globally on your system using npm.

```bash
npm install -g node-red-contrib-modbus@3.6.1
```

--------------------------------

### Install Node.js without NPM

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Raspberry-PI2-and-PI3-hints

Installs Node.js using the system's package manager, suitable when NPM is not preferred or available.

```bash
sudo apt-get install nodejs
```

```bash
sudo apt install nodejs
```

--------------------------------

### Install Node-RED Modbus Package

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/README.md

Use this command to install the package in your Node-RED project directory. For global installation, use the -g flag.

```bash
npm install node-red-contrib-modbus
```

```bash
npm install -g node-red-contrib-modbus
```

--------------------------------

### Install Node.js 6.9.2 using N

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Raspberry-PI2-and-PI3-hints

Use this command to downgrade or install Node.js version 6.9.2 on your system using the 'n' version manager.

```bash
sudo npm cache clean -f
sudo npm install -g n
sudo n 6.9.2
```

--------------------------------

### Get Modbus IO File Value Names via HTTP

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

This example shows how to retrieve a list of all available IO file value names using an HTTP GET request to the Node-RED admin endpoint. It requires an authorization token.

```javascript
// HTTP Admin endpoint — get all IO file value names
// GET /modbus/iofile/valuenames
// curl -H "Authorization: Bearer <token>" http://localhost:1880/modbus/iofile/valuenames
// Response: ["SDM630 Phase 1 line to neutral volts", "SDM630 Phase 2 ...", ...]
```

--------------------------------

### Install Data Generator Node

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Raspberry-PI2-and-PI3-hints

Installs the node-red-node-data-generator package globally. Use --unsafe-perm and --build-from-source if encountering permission or build issues.

```bash
sudo npm install -g node-red-node-data-generator --unsafe-perm --build-from-source
```

--------------------------------

### List Available Serial Ports via HTTP GET

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

Retrieve a list of available serial ports on the system using the /modbus/serial/ports HTTP GET endpoint. Requires the 'serialport' optional dependency to be installed.

```bash
# List all available serial ports (requires serialport optional dependency) 
# GET /modbus/serial/ports
curl -H "Authorization: Bearer <token>" \
     http://localhost:1880/modbus/serial/ports
# Response: [{ path: "/dev/ttyUSB0", manufacturer: "..." }, ...]
```

--------------------------------

### Install Node-RED Modbus Contrib

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Raspberry-PI2-and-PI3-hints

Installs the node-red-contrib-modbus package globally. Use --unsafe-perm and --build-from-source if encountering permission or build issues.

```bash
sudo npm install -g node-red-contrib-modbus --unsafe-perm --build-from-source
```

--------------------------------

### Install Node.js 6.9 LTS on Raspberry Pi

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Raspberry-PI

Download, extract, and install Node.js version 6.9.2 LTS for ARMv6l architecture on a Raspberry Pi. This involves using wget, tar, cp, and reboot commands.

```bash
wget https://nodejs.org/dist/v6.9.2/node-v6.9.2-linux-armv6l.tar.gz
```

```bash
tar -xvf node-v6.9.2-linux-armv6l.tar.gz
```

```bash
cd node-v6.9.2-linux-armv6l
```

```bash
sudo cp -R * /usr/local/
```

```bash
sudo reboot
```

```bash
node -v
```

--------------------------------

### Start Node-RED with sudo

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Port-502-on-PI-or-PC

To provide a Modbus virtual server with port 502, you must start Node-RED with sudo privileges. This is because port 502 is a well-known port (0-1023) and requires elevated rights.

```bash
sudo node-red
```

--------------------------------

### Install Node.js 4.7 LTS on Raspberry Pi

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Raspberry-PI

Download, extract, and install Node.js version 4.7.2 LTS for ARMv6l architecture on a Raspberry Pi. This involves using wget, tar, cp, and reboot commands.

```bash
wget https://nodejs.org/dist/v4.7.2/node-v4.7.2-linux-armv6l.tar.gz
```

```bash
tar -xvf node-v4.7.2-linux-armv6l.tar.gz
```

```bash
cd node-v4.7.2-linux-armv6l
```

```bash
sudo cp -R * /usr/local/
```

```bash
sudo reboot
```

```bash
node -v
```

--------------------------------

### Modbus Flex Connector SERIAL Example

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/src/modbus-flex-connector.html

Example of configuring the Modbus Flex Connector for a Serial connection. Specifies the serial port and baud rate.

```javascript
msg.payload = { 'connectorType': 'SERIAL', 'serialPort': '/dev/USB02', 'serialBaudrate': '9600' 'unitId': 2 }
return msg
```

--------------------------------

### IO-File JSON Format Example

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/src/modbus-io-config.html

Example of the JSON-IO-File format used to define Modbus registers and coils. This format is derived from CODESYS CSV export.

```json
{
    "name": "Modbus Holding Registers",
    "valueAddress": "%IW0"
}
{
    "name": "iCountDummyBorder",
    "valueAddress": "%IW0"
}
{
    "name": "bReset",
    "valueAddress": "%IX8.0"
}
{
    "name": "Modbus Input Registers",
    "valueAddress": "%QW0"
}
{
    "name": "iBooleanSetOne",
    "valueAddress": "%QW4"
}
{
    "name": "bOperationActive",
    "valueAddress": "%QX8.0"
}
```

--------------------------------

### Modbus Flex Getter: Multiple Inputs Read

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/src/modbus-flex-getter.html

Configure the node to read multiple Modbus inputs. This example reads 10 registers starting from address 0 using function code 3.

```javascript
msg.payload = { value: msg.payload, 'fc': 3, 'unitid': 1, 'address': 0 , 'quantity': 10 }
return msg
```

--------------------------------

### Modbus Flex Connector TCP Example

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/src/modbus-flex-connector.html

Example of how to configure the Modbus Flex Connector for a TCP connection using a function node. Sets the connector type, host, and unit ID.

```javascript
msg.payload = { 'connectorType': 'TCP', 'tcpHost': '127.0.0.1', 'unitId': 2 }
return msg
```

--------------------------------

### Get IO File Value Names via HTTP GET

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

Fetch a list of IO file value names using the /modbus/iofile/valuenames HTTP GET endpoint. This is useful for populating dropdowns or configuration options related to Modbus IO files.

```bash
# Get IO file value names (for response filter dropdowns)
# GET /modbus/iofile/valuenames
curl -H "Authorization: Bearer <token>" \
     http://localhost:1880/modbus/iofile/valuenames
# Response: ["Register Name 1", "Register Name 2", ...]
```

--------------------------------

### Install Specific Version of Node-RED Modbus

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/README.md

Use npm to install a specific version of the node-red-contrib-modbus package by appending the version number with an '@' symbol.

```bash
npm install node-red-contrib-modbus@3.6.1
```

--------------------------------

### Verify Node.js Version

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Raspberry-PI2-and-PI3-hints

Checks the currently installed Node.js version. Ensure it meets the required version constraints (>=4.7.0 or <=6.9.2).

```bash
node -v
```

--------------------------------

### Modbus Flex Connector TCP with Port Example

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/src/modbus-flex-connector.html

Example of configuring the Modbus Flex Connector for TCP, including the port number. This allows specifying a non-default port for the Modbus TCP server.

```javascript
msg.payload = { 'connectorType': 'TCP', 'tcpHost': '127.0.0.1', 'tcpPort': '10502', 'unitId': 2 }
return msg
```

--------------------------------

### Activate Modbus Debugging

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/README.md

Enable detailed debugging output for node-red-contrib-modbus by setting the DEBUG environment variable when starting Node-RED.

```bash
DEBUG=contribModbus*,modbus-serial node-red -v
```

```bash
DEBUG=contribModbus:{option},contribModbus:{option},...
```

--------------------------------

### Complete Modbus Flow Example

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

This JSON represents a complete Node-RED flow demonstrating a Modbus TCP client, an embedded Modbus server, automatic reading, and a write operation. It includes configurations for the client, server, read, response, inject, function, and flex-write nodes.

```json
[{"id":"tcp_client","type":"modbus-client","name":"My PLC","clienttype":"tcp","bufferCommands":true,"tcpHost":"127.0.0.1","tcpPort":"14502","tcpType":"DEFAULT","unit_id":1,"commandDelay":1,"clientTimeout":1000,"reconnectOnTimeout":true,"reconnectTimeout":2000,"parallelUnitIdsAllowed":true},{"id":"embedded_server","type":"modbus-server","hostname":"0.0.0.0","serverPort":"14502","responseDelay":"50","delayUnit":"ms","coilsBufferSize":1024,"holdingBufferSize":1024,"inputBufferSize":1024,"discreteBufferSize":1024,"showErrors":true,"wires":[["dbg_holding"],[],[],[],[]]},{"id":"auto_read","type":"modbus-read","dataType":"HoldingRegister","adr":"0","quantity":"10","rate":"5","rateUnit":"s","delayOnStart":true,"startDelayTime":"2","server":"tcp_client","emptyMsgOnFail":false,"wires":[["dbg_values"],["resp_node"]]},{"id":"resp_node","type":"modbus-response","registerShowMax":"10","wires":[]},{"id":"write_trigger","type":"inject","payload":"[100,200,300,400,500,600,700,800,900,1000]","payloadType":"json","wires":[["build_write_msg"]]},{"id":"build_write_msg","type":"function","func":"msg.payload = { value: msg.payload, fc: 16, unitid: 1, address: 0, quantity: 10 };\nreturn msg;","wires":[["flex_write"]]},{"id":"flex_write","type":"modbus-flex-write","server":"tcp_client","emptyMsgOnFail":true,"keepMsgProperties":false,"wires":[["dbg_write_done"],["resp_write"]]},{"id":"resp_write","type":"modbus-response","registerShowMax":"10","wires":[]}]
```

--------------------------------

### Custom Function Code Message Example

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/src/modbus-flex-fc.html

This example demonstrates the structure of a message object used for custom Modbus function codes, including request and response argument definitions.

```javascript
msg = { topic: 'customFc', from: 'Requester-Name', payload: { unitid: 1, fc: 3, requestCard:[{ name: 'Read Registers Request Definition', data: 0, offset: 0, type: 'uint16be' }], responseCard: [{ name: 'Read Registers Answer Definition', data: 0, offset: 0, type: 'uint16be' }] messageId: mbCore.getObjectId() } }
```

--------------------------------

### HTTP Admin Endpoint: List Serial Ports

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

Retrieves a list of available serial ports on the system. This endpoint requires the `serialport` optional dependency to be installed.

```APIDOC
## HTTP Admin Endpoints

```bash
# List all available serial ports (requires serialport optional dependency)
# GET /modbus/serial/ports
curl -H "Authorization: Bearer <token>" \
     http://localhost:1880/modbus/serial/ports
# Response: [{ path: "/dev/ttyUSB0", manufacturer: "..." }, ...]
```
```

--------------------------------

### Modbus Server Input Payload Example

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/src/modbus-server.html

Demonstrates how to send a message payload to the Modbus Server node to write data to its registers. This is useful for simulating a Modbus client writing to the server.

```javascript
msg.payload = { 'value': msg.payload, 'register': 'holding', 'address': 1 , 'disableMsgOutput' : 0 };
return msg;
```

--------------------------------

### modbus-flex-fc Node Configuration

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

Configuration example for the `modbus-flex-fc` node, which allows sending custom Modbus function codes with defined request and response byte-array structures.

```APIDOC
## Node: modbus-flex-fc (Custom Function Code)

The `modbus-flex-fc` node sends a custom Modbus function code using a request/response byte-array definition. It is designed for vendor-specific or non-standard Modbus function codes beyond FC1–FC4 and FC5/6/15/16.

```json
// Node-RED flow JSON — custom FC node
{
  "id": "fc1",
  "type": "modbus-flex-fc",
  "name": "Custom FC 0x43",
  "unitid": "1",
  "fc": "0x43",
  "requestCard": "0x43 0x00 0x00",
  "responseCard": "0x43 ?? ??",
  "server": "client1",
  "emptyMsgOnFail": true,
  "wires": [["debug_custom_response"]]
}
```
```

--------------------------------

### Continuous Offset Example in Request Map

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/extras/argumentMaps/ArgumentMaps.md

Illustrates the requirement for continuous offsets within a `requestMap`. This example shows a 16-bit value at offset 0, followed by an empty byte (not described in the map), and then an 8-bit value at offset 3, which would cause a parser error due to the gap.

```json
    "requestMap":
    [
        { "name": "foo", "data": 0, "offset": 0, "type": "uint16be" },
        { "name": "bar", "data": 1, "offset": 3, "type": "uint8be"  }
    ]
```

--------------------------------

### Modbus Single Write Example

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/src/modbus-flex-write.html

Use this code in a Function node to perform a single Modbus write operation. Ensure 'fc', 'unitid', 'address', and 'quantity' are correctly set.

```javascript
msg.payload = { value: msg.payload, 'fc': 5, 'unitid': 1, 'address': 0 , 'quantity': 1 }
return msg
```

--------------------------------

### HTTP Admin Endpoint: Get IO File Value Names

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

Fetches a list of value names for IO files. This is typically used to populate dropdowns or selection lists within the Node-RED interface.

```APIDOC
```bash
# Get IO file value names (for response filter dropdowns)
# GET /modbus/iofile/valuenames
curl -H "Authorization: Bearer <token>" \
     http://localhost:1880/modbus/iofile/valuenames
# Response: ["Register Name 1", "Register Name 2", ...]
```
```

--------------------------------

### Modbus Multiple Write Example

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/src/modbus-flex-write.html

Use this code in a Function node to perform multiple Modbus write operations. Adjust 'fc', 'unitid', 'address', and 'quantity' as needed for your Modbus device.

```javascript
msg.payload = { value: msg.payload, 'fc': 15, 'unitid': 1, 'address': 0 , 'quantity': 10 }
return msg
```

--------------------------------

### Node-RED Example Flow for Modbus Buffer Manipulation

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Buffer-swap-and-endianness

This JSON represents a Node-RED flow that demonstrates reading Modbus data, extracting buffer information, and performing endianness swaps. It includes nodes for Modbus reading, function nodes for data processing, and debug nodes for output.

```json
[{"id":"18ea8042.ed0f2","type":"modbus-read","z":"325a2317.7214fc","name":"Automatic Read FC3","showStatusActivities":false,"unitid":"","dataType":"HoldingRegister","adr":"200","quantity":"10","rate":"1","rateUnit":"s","server":"","x":250,"y":200,"wires":[[ "4842691f.156838" ],[ "78c57d11.312d94", "7c3a39bf.40b348", "33239b9c.7605b4", "4d64be9f.20935" ]]},{"id":"78c57d11.312d94","type":"debug","z":"325a2317.7214fc","name":"","active":false,"console":"false","complete":"true","x":450,"y":240,"wires":[]},{"id":"7c3a39bf.40b348","type":"function","z":"325a2317.7214fc","name":"extract buffer","func":"return [{ payload: msg.payload.buffer.readInt16LE(0,2)},
{ payload: msg.payload.buffer.readInt16BE(0,2) }];","outputs":"2","noerr":0,"x":470,"y":280,"wires":[[ "656af465.503b3c" ],[ "656af465.503b3c" ]]},{"id":"33239b9c.7605b4","type":"modbus-response","z":"325a2317.7214fc","name":"","registerShowMax":20,"x":490,"y":160,"wires":[]},{"id":"4842691f.156838","type":"debug","z":"325a2317.7214fc","name":"","active":false,"console":"false","complete":"false","x":470,"y":120,"wires":[]},{"id":"656af465.503b3c","type":"debug","z":"325a2317.7214fc","name":"","active":false,"console":"false","complete":"false","x":650,"y":280,"wires":[]},{"id":"4d64be9f.20935","type":"function","z":"325a2317.7214fc","name":"swap buffer","func":"msg.payload.buffer.swap16()\nreturn { payload: msg.payload.buffer };","outputs":"1","noerr":0,"x":470,"y":320,"wires":[[ "6ed544fa.dcce3c" ]]},{"id":"6ed544fa.dcce3c","type":"debug","z":"325a2317.7214fc","name":"","active":false,"console":"false","complete":"false","x":650,"y":320,"wires":[]}]
```

--------------------------------

### Configure TCP Connector (Basic)

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Modbus-Flex-Connector

Use this in a function node to configure a TCP connection. Specify the host and unit ID.

```javascript
msg.payload = { 'connectorType': 'TCP', 'tcpHost': '127.0.0.1', 'unitId': 2 } 
return msg 
```

--------------------------------

### Configure TCP Connector (with Port)

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Modbus-Flex-Connector

Use this in a function node to configure a TCP connection, including a specific port. Specify the host, port, and unit ID.

```javascript
msg.payload = { 'connectorType': 'TCP', 'tcpHost': '127.0.0.1', 'tcpPort': '10502', 'unitId': 2 } 
return msg
```

--------------------------------

### Reboot System

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Raspberry-PI2-and-PI3-hints

Reboots the Raspberry Pi system. This is often necessary after system changes or installations.

```bash
sudo reboot
```

--------------------------------

### Read 64-bit Buffer Node-RED

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Buffer-8Bit,-16Bit,-32Bit,-64Bit,-128Bit-...-reading-with-SDM630-power-meter

Use the `read` method with offset 0 and length 8 to read the first 64-bit value from the buffer.

```javascript
msg.payload.buffer.read...(0,8)
```

--------------------------------

### Configure Single Modbus Sequence

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/src/modbus-flex-sequencer.html

Use this code in a Function node to define a single Modbus read sequence. Specify the function code, starting address, unit ID, and quantity of registers.

```javascript
msg.sequences = [
  { name : "Foo", fc : 1, address : 1, unitid: 2, quantity : 6 }
]
return msg;
```

--------------------------------

### Configure Modbus Queue Monitor

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

Configure the modbus-queue-info node to monitor the Modbus client's command queue depth for a specific unit ID. Set thresholds for low, high, and critical queue levels. The 'server' property must match your Modbus client configuration.

```json
// Node-RED flow JSON — queue monitor for unit 1
{
  "id": "queue1",
  "type": "modbus-queue-info",
  "name": "PLC Queue Monitor",
  "topic": "queue",
  "unitid": "1",
  "queueReadIntervalTime": "1000",
  "lowLowLevel": 25,
  "lowLevel": 75,
  "highLevel": 150,
  "highHighLevel": 300,
  "errorOnHighLevel": false,
  "showStatusActivities": true,
  "updateOnAllQueueChanges": false,
  "updateOnAllUnitQueues": false,
  "server": "client1",
  "wires": [["debug_queue_state"]]
}
// Output when high level reached:
// msg = {
//   payload: 1700000000000,  // Date.now()
//   state: "high level reached",
//   unitid: 1,
//   modbusClientName: "PLC Over TCP",
//   highLevel: 150,
//   bufferCommandListLength: 165
// }
```

--------------------------------

### Overriding Custom FC Parameters at Runtime

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

Example of how to dynamically override custom Modbus function code parameters (unit ID, function code, request/response card) using an input message payload.

```APIDOC
## Override custom FC parameters at runtime via input message

```js
// Override custom FC parameters at runtime via input message
msg = {
  topic: "customFc",
  payload: {
    unitid: 1,
    fc: 0x43,
    requestCard: "0x43 0x00 0x01",
    responseCard: "0x43 ?? ??",
    from: "myNode"
  }
}
return msg
// Output msg.payload: full response object from modbus-serial
```
```

--------------------------------

### Override Modbus Sequencer at Runtime

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

This JavaScript example shows how to dynamically override the Modbus flex-sequencer's read sequence at runtime by setting the `msg.sequences` property. Each entry in the array defines a read operation.

```javascript
// Override sequences at runtime via msg.sequences
msg.sequences = [
  { name: "Dynamic Read", unitid: 2, fc: 3, address: 100, quantity: 10 },
  { name: "Input Check",  unitid: 2, fc: 4, address: 0,   quantity: 5  }
]
return msg
// Each sequence entry produces a separate output message on output 1
```

--------------------------------

### Read 32-bit Buffer Node-RED

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Buffer-8Bit,-16Bit,-32Bit,-64Bit,-128Bit-...-reading-with-SDM630-power-meter

Use the `read` method with offset 0 and length 4 to read the first 32-bit value from the buffer.

```javascript
msg.payload.buffer.read...(0,4)
```

--------------------------------

### Node-RED Flow: Static Modbus Read (modbus-getter)

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

Configures a modbus-getter node to read 10 holding registers starting from address 0 on unit ID 1. This flow is triggered by an inject node.

```json
// Node-RED flow JSON — getter wired to an inject node
[
  {
    "id": "inj1",
    "type": "inject",
    "repeat": "2",
    "once": true,
    "onceDelay": "2",
    "payload": "",
    "payloadType": "date",
    "wires": [["getter1"]]
  },
  {
    "id": "getter1",
    "type": "modbus-getter",
    "name": "Manual Getter FC3",
    "unitid": "1",
    "dataType": "HoldingRegister",
    "adr": "0",
    "quantity": "10",
    "server": "client1",
    "emptyMsgOnFail": true,
    "keepMsgProperties": false,
    "showStatusActivities": false,
    "showErrors": false,
    "wires": [["debug_values"], ["debug_response"]]
  }
]
// Output 1 msg.payload: [10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
```

--------------------------------

### Read 8-bit Buffer Node-RED

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Buffer-8Bit,-16Bit,-32Bit,-64Bit,-128Bit-...-reading-with-SDM630-power-meter

Use the `read` method with offset 0 and length 1 to read the first 8-bit value from the buffer.

```javascript
msg.payload.buffer.read...(0,1)
```

--------------------------------

### Configure Modbus Flex Sequencer

Source: https://context7.com/biancoroyal/node-red-contrib-modbus/llms.txt

Configure the modbus-flex-sequencer node to execute a predefined sequence of Modbus read requests. Each sequence entry specifies function code, unit ID, address, and quantity. The 'server' property must match your Modbus client configuration.

```json
// Node-RED flow JSON — sequencer reading coils from two address ranges
{
  "id": "seq1",
  "type": "modbus-flex-sequencer",
  "name": "Multi-Read Sequence",
  "sequences": [
    { "name": "Coils 1-2",   "unitid": "1", "fc": "FC1", "address": "1",  "quantity": "2" },
    { "name": "Coils 10-11", "unitid": "1", "fc": "FC1", "address": "10", "quantity": "2" },
    { "name": "Regs 0-4",   "unitid": "1", "fc": "FC3", "address": "0",  "quantity": "5" }
  ],
  "server": "client1",
  "showErrors": true,
  "emptyMsgOnFail": true,
  "keepMsgProperties": true,
  "delayOnStart": true,
  "startDelayTime": "2",
  "wires": [["debug_values"], ["debug_response"]]
}
```

--------------------------------

### Configure SERIAL Connector

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Modbus-Flex-Connector

Use this in a function node to configure a SERIAL connection. Specify the serial port, baud rate, and unit ID.

```javascript
msg.payload = { 'connectorType': 'SERIAL', 'serialPort': '/dev/USB02', 'serialBaudrate': '9600' 'unitId': 2 } 
return msg
```

--------------------------------

### Read 16-bit Buffer Node-RED

Source: https://github.com/biancoroyal/node-red-contrib-modbus/wiki/Buffer-8Bit,-16Bit,-32Bit,-64Bit,-128Bit-...-reading-with-SDM630-power-meter

Use the `read` method with offset 0 and length 2 to read the first 16-bit value from the buffer.

```javascript
msg.payload.buffer.read...(0,2)
```

--------------------------------

### Modbus Flex Sequencer Configuration

Source: https://github.com/biancoroyal/node-red-contrib-modbus/blob/master/src/modbus-flex-sequencer.html

This JavaScript code configures the Modbus Flex Sequencer node, including handling sequence definitions and resizing the editor. It pushes sequence configurations to the node's `sequences` array.

```javascript
sequences: $("#node-input-sequences-container").editableList({
        addItem: function (node, item, $item) {
            if (item) {
                $(".node-input-unitid", $item).val(item.unitid);
                $(".node-input-function", $item).val(item.fc);
                $(".node-input-address", $item).val(item.address);
                $(".node-input-quantity", $item).val(item.quantity);
            }
        },
        sortable: true,
        removable: true,
        addGroup: function ($item) {
            var $group = $(
                "<div><ol style=\"margin: 6px 0 0px;\">
                </ol></div>"
            );
            return $group;
        },
        add: function ($item) {
            var $node = $(
                "<li><div class=\"form-row\">
                <label style=\"width:100px\" for=\"node-input-unitid\"><i class=\"fa fa-server\"></i> Unit ID</label>
                <input type=\"text\" id=\"node-input-unitid\" style=\"width:70px\">
                <label style=\"width:100px\" for=\"node-input-function\"><i class=\"fa fa-list\"></i> Function</label>
                <input type=\"text\" id=\"node-input-function\" placeholder=\"1-4\" style=\"width:70px\">
                <label style=\"width:100px\" for=\"node-input-address\"><i class=\"fa fa-map-marker\"></i> Address</label>
                <input type=\"text\" id=\"node-input-address\" placeholder=\"0-65535\" style=\"width:70px\">
                <label style=\"width:100px\" for=\"node-input-quantity\"><i class=\"fa fa-arrows-h\"></i> Quantity</label>
                <input type=\"text\" id=\"node-input-quantity\" placeholder=\"1-65535\" style=\"width:70px\">
                </div></li>"
            );
            $(".node-input-sequences-container", $item).append($node);
            return $node;
        }
    });
    $("#node-input-sequences-container").val(JSON.stringify(node.sequences));
}, oneditresize: function (size) { var height = size.height; $('#node-input-sequences-container').css("height", (height - 145) + "px"); } })
```