node-red-contrib-remote-io/wago/WAGO_AI.js

A sample node for node-red

module.exports = function(RED) {
    "use strict";

    function analogInput(n) {
       RED.nodes.createNode(this,n);
       //var context = this.context();
       var node = this;
       var sensorType = n.sensorType;
       var resolution = n.resolution;
       var low = n.low;
       var high = n.high;
       var prec = n.precision;
       var selectedProcess = n.selectedProcess;

       // scales number
     function scale(x, i_lo, i_hi, o_lo, o_hi)    {
            var multiplier = (o_hi - o_lo) / (i_hi - i_lo);
            var scaledVal = (multiplier * limit(i_lo, x, i_hi)) + o_lo;
            return(scaledVal);
        }
        function limit(i_lo, x, i_hi){
            var last = 0;
            if (x<i_lo){
                return(i_lo);
            } else {
                if (x>i_hi){
                    return(i_hi);
                } else {
                    return(x);
                }
            }
        }
       function toFixed( num, precision ) {
        return (+(Math.round(+(num + 'e' + precision)) + 'e' + -precision)).toFixed(precision);
        }
        this.on('input', function(msg) {
            var rawInput = parseInt(msg.payload);
            var rawMinInput = 0;
            var rawMaxInput = 0;
            var outputMsg = {};
            var actualSensorValue;
	        var val_10vdc = 0;
	        var val_int16 = 0;
	        var val_scaled = 0;
            // set the max value
            switch(resolution)  {
                case "12_Bit":
                    rawMaxInput = 32767;
                    break;
                case "13_Bit":
                    rawMaxInput = 32767;
                    break;
                case "13_Bit_signed":
                	rawMinInput = -32767;
                    rawMaxInput = 32767;
                    break;
                case "14_Bit":
                    rawMaxInput = 32767;
                    break;
                case "15_Bit":
                    rawMaxInput = 32767;
                    break;
                case "15_Bit_signed":
                	rawMinInput = -32767;
                    rawMaxInput = 32767;
                    break;
                case "16_Bit":
                    rawMaxInput = 65535;
                    break;                
            }
            switch(sensorType)  {
                case "0-20mA":
                    actualSensorValue = scale(msg.payload, rawMinInput, rawMaxInput, 0, 20);
                    break;
                case "4-20mA":
                    actualSensorValue = scale(msg.payload, rawMinInput, rawMaxInput, 4, 20);
                    break;
                case "0-10VDC":
                    actualSensorValue = scale(msg.payload, rawMinInput, rawMaxInput, 0, 10);
                    break;
                case "+/-10VDC": // meeds work
                	if (msg.payload <= 32767){
                		val_10vdc = scale(msg.payload, 0, rawMaxInput, 0, 10);
                		actualSensorValue = val_10vdc;	 
                		val_int16 = msg.payload;
                	} else {
	                	val_10vdc = (msg.payload << 1); 	
	                	val_10vdc = (val_10vdc >> 1); 
	                	val_10vdc = val_10vdc * -1;	
	                    val_int16 = val_10vdc + 32767; 
	                    //val_10vdc = scale(val_10vdc, rawMinInput, rawMaxInput, -10, 0);  
	                    val_10vdc = scale(val_int16, rawMinInput, 0, -10, 0) + 10;  
                        actualSensorValue = val_10vdc;	                     
	                }
                    break;
                case "0-30VDC":
                    actualSensorValue = scale(msg.payload, rawMinInput, rawMaxInput, 0, 30);
                    break;
            }
            // operation based on processSelected
            switch(selectedProcess) {
                case "Raw":   
                	if (sensorType == "+/-10VDC"){
                		val_int16 = val_int16; // assigned above
                	} else {
 						val_int16 = msg.payload;
					}
					outputMsg.payload = val_int16;
                    break;
                case "SensorVal":
                    outputMsg.payload = parseFloat(toFixed(actualSensorValue, prec));
                    break;
                case "Scaled":
                	if (sensorType == "+/-10VDC"){
                    	var scaledHold = scale(val_10vdc+ 10, 0, 20, low, high);
                    } else {
                    	var scaledHold = scale(msg.payload, rawMinInput, rawMaxInput, low, high);
                    }
                    outputMsg.payload = parseFloat(toFixed(scaledHold, prec));
                break;
            }
            node.send(outputMsg);
        });
    }
    RED.nodes.registerType("Analog Input",analogInput);
};