honcho

Honcho is a multiple PLC connection manager for Node.JS using nodes7/nodepccc/mcprotocol or other libraries that use a similar API to those.

Normally Honcho will be called by a program that configures it and subscribes to its polls, like a server that streams PLC data over a Websocket or TCP stream.

Honcho is initially configured by a configuration object and multiple PLC tag files.

First create a tag to address translation file using a text editor:

testplctags.txt should have only one line for the following example to work: MYTAG=DB99,INT0

Example application:

var honcho = require('honcho');

config = {
	defaultController: 'TESTPLC',
	tagFileDir: '.',
	controllers: [
		{ host: '192.168.1.2',
		connection_name: 'TESTPLC',
		port: 102,
		slot: 1, 	/* See NodeS7 docs - slot 1 for 1200/1500, slot 2 for 300 */
		type: 'nodes7',
  			tagfile: './testplctags.txt' }
		],

	/* Define one or more tagsets to be subscribed to */
	tagsets: ['status'],

	/* Define one or more tags to be subscribed to */
	tags : {
		'MYTAG':{
		tagsets:['status']
		}		
	}
};

function readDone(err, vars) {
	console.log(vars);
	// Or stream to a Websocket, etc
}

honcho.configure(config, function(){
	honcho.createSubscription(['MYTAG'], readDone, 500);
});

This will log the following every 500ms:

{ MYTAG: 0 }

API

• configure()
• findItem()
• read()
• write()
• createSubscription()
• removeSubscription()

honcho.configure(config, callback)

Sets up the configuration and calls the callback when done. Please see above for configuration syntax.

honcho.findItem(item, callback)

Retuns the full "item" from the PLC driver in the callback.

honcho.read(tags, callback)

Reads specific tags and runs a callback with their values. Note the callback is called as callback(err, values).

honcho.write(tag, value, callback)

Writes a specific tag and runs an optional callback with the result.

honcho.createSubscription(tag array, callback, interval)

Sets up a subscription that will return the values of listed tags every timeout via the callback. Returns a token useful for removing subscriptions. Note the callback is called as callback(err, values).

honcho.removeSubscription(token)

Removes a subscription using a token returned when creating it.