Node.js® JavaScript Module Example Implementation

Setting up a JavaScript Module

1. To create a new JavaScript module, first find the templates provided by WinCC OA in the folder javascript/templates/javascript in your WinCC OA installation directory.
2. In your WinCC OA project, create a path called javascript/<modulename> (where <modulename> is the name you want to use for your module) and copy the contents of the templates folder from step 1 into <modulname>.
   Note:

   In case the copied files are read-only, it is necessary to enable write access using OS tools
3. In javascript/<modulname>/package.json, replace the value for "name" with the name of the module, which must be the same as the directory name by convention, e.g.:

   {
    "name": "<modulename>",
    ...
   }

4. Open a command prompt in the copied javascript/<modulename> directory.
5. Call the following command to install required modules

   npm install

6. Add a JavaScript Manager with the path of index.js in the copied directory as its only parameter (relative to directory javascript, e.g.: <modulename>/index.js). Set Start mode to manual

   

7. Start the manager - it will terminate immediately
8. Check that the message "JavaScript Manager for WinCC OA working" is shown in the Log Viewer.
9. Start developing. Below you can find the JavaScript module example:

   'use strict';
   // The command line for the Node.js® manager must contain the path to
   // this file relative to data/nodejs, e. g.:
   //
   // modulename/index.js
   
   // require WinCC OA interface
   const { WinccoaManager } = require('winccoa-manager');
   const winccoa = new WinccoaManager();
   
   // main function
   async function main() {
     const dpeName = 'ExampleDP_Arg1.';
     const value = await winccoa.dpGet(dpeName);
   
     console.info('Node.js® manager for WinCC OA working');
     console.info('Value of ' + dpeName + ' = ' + value);
   
     winccoa.exit(0);
   }
   
   // start the main function
   main();

   Note:

   JavaScript code must be called from inside a method or function to prevent unexpected or undefined behavior.
10. (optional, but recommended) Check and format your code with:

    npm run lint
    npm run format

npm install --save-dev