OPC UA to MySQL Data Logger using JavaScript

OPC UA to MySQL Data Logger

This project reads tag values from an OPC UA server and logs them into a MySQL database at a configurable interval. Tag details are loaded from a CSV file, and all configuration is managed via a JSON config file.

Features

• Batch reading of OPC UA tags for performance (all tag values read in one request)
• Batch logging to MySQL (all changed values inserted in a single query per polling interval)
• Only logs to MySQL when values change (no duplicate data)
• Configurable OPC UA endpoint, credentials, polling interval, MySQL database/table name, and CSV file
• Automatic MySQL reconnection: if connection drops, the logger will retry every 2 seconds and resume logging once reconnected
• Automatic OPC UA reconnection: if connection or session drops, the logger will retry and resume data logging once reconnected
• Table creation only runs once after first successful connection
• Debug logging for troubleshooting
• Graceful shutdown: closes OPC UA session/client and MySQL DB cleanly on Ctrl+C or SIGTERM

Files

• server.js — Main script for reading OPC UA data and logging to MySQL
• config.json — Configuration file for endpoint, credentials, polling interval, database/table, and CSV file
• tags.csv — CSV file listing tag names and nodeIds to read

Configuration

Edit config.json to set your parameters:

{
  "opcuaEndpoint": "opc.tcp://localhost:4840",
  "opcuaUsername": "", // optional
  "opcuaPassword": "", // optional
  "mysqlDbName": "test",
  "mysqlTableName": "tag_data",
  "mysqlHost": "127.0.0.1",
  "mysqlUser": "root",
  "mysqlPassword": "toor",
  "pollIntervalMs": 1000,
  "tagsCsvFile": "tags.csv"
}

Tag CSV Format

Example tags.csv:

name,nodeId
Constant,ns=3;i=1001
Counter,ns=3;i=1002
Random,ns=3;i=1003

Usage

1. Install dependencies:

   npm install
   

2. Start the logger:

   node server.js
   

3. Inspect the database using a MySQL client (e.g., MySQL Workbench, DBeaver).

Notes

• Only changed values are logged to avoid duplicate data.
• If MySQL connection drops during runtime, the logger will automatically reconnect and resume logging.
• Debug output is printed to the console for each read and database insert.
• Graceful shutdown: Press Ctrl+C or send SIGTERM to close all connections and DB cleanly.
• Make sure your OPC UA server is running and accessible.
• You can change the polling interval, database/table name, and CSV file in config.json.