I'm expecting a different output....

I'm trying to receive a value from my temp sensor. Expect I'm receiving "77 r" (without quotes). I should be receiving a number value.

code:

I2C1.setup({scl:B8, sda:B9});

Serial2.setup(9600/*baud*/);

var resTempVal = "";
var phVal = "";
var ecVal = "";

var ready = true;
var alwaysTempCompensate = false;

function Sensor(id, type, address) {
    this.sensorName = id;
    this.sensorType = type;
    this.sensorAddress = address;
    this.sensorRequireTempComp = false;

    this.resTempCal = {
      "clear" : { "cmd" : "Cal,Clear", "wait" : 300  },
      "one"   : { "cmd" : "Cal,n",     "wait" : 1300 },
      "query" : { "cmd" : "Cal,?",     "wait" : 300  }
    };

    this.phCal = {
      "clear" : { "cmd" : "Cal,Clear",      "wait" : 300  },
      "mid"   : { "cmd" : "Cal,mid,7.00",   "wait" : 1300 },
      "low"   : { "cmd" : "Cal,low,4.00",   "wait" : 1300 },
      "high"  : { "cmd" : "Cal,high,10.00", "wait" : 1300 },
      "query" : { "cmd" : "Cal,?",          "wait" : 300  }
    };

    this.ecCal = {
      "clear" : { "cmd" : "Cal,Clear",  "wait" : 300  },
      "dry"   : { "cmd" : "Cal,dry",    "wait" : 2000 },
      "one"   : { "cmd" : "Cal,one,n",  "wait" : 1300 },
      "low"   : { "cmd" : "Cal,low,n",  "wait" : 1300 },
      "high"  : { "cmd" : "Cal,high,n", "wait" : 1300 },
      "query" : { "cmd" : "Cal,?",      "wait" : 300  }
    };

    this.cmdTable = {
      "Calibrate" : {  //List of Calibration commands and timeout value.
      },
      "Information" : {  //Device Information
      },
      "LED" : {  //Enable / Disable or Query the LEDs
        "L0" : { "cmd" : "L,0", "wait" : 300 },
        "L1" : { "cmd" : "L,1", "wait" : 300 },
        "L?" : { "cmd" : "L,?", "wait" : 300 }
      },
      "Reading" : {  //Takes a single reading
        "R" : { "cmd" : "r", "wait" : 1000 } //Takes a single temperature compensated reading
      },
      "Serial"      : {  //Switch back to UART mode
      },
      "Sleep"       : {  //Enter low power sleep mode
      },
      "Status"      : {  //Retrieve status information
      },
      "Temperature" : {  //Set or Query the temperature compensation
        "T"  : { "cmd" : "T", "wait" : 300 },  //Where the temperature is any value; floating point, or int, in ASCII form
        "T?" : { "cmd" : "T,?",   "wait" : 300 }  //Query the set temerature
      },
      "Factory"     : {  //Factory reset
      },
    };

    if (type == "temp") {
      this.cmdTable.Calibrate = this.resTempCal;
      //console.log(this.cmdTable.Calibrate);
    }

    if (type == "ph") {
      this.cmdTable.Calibrate = this.phCal;
      //console.log(this.cmdTable.Calibrate);
      this.sensorRequireTempComp = true;
    }

    if (type == "ec") {
      this.cmdTable.Calibrate = this.ecCal;
      //console.log(this.cmdTable.Calibrate);
      this.sensorRequireTempComp = true;
    }
}

Sensor.prototype.updateTempComp = function (temp) {
  this.cmdTable.Temperature.T.cmd = "T," + temp;
};

Sensor.prototype.takeReading = function() {
  var a = this.sensorAddress;
  var c = this.cmdTable.Reading.R.cmd;
  var w = this.cmdTable.Reading.R.wait;

  var d = "";
  var sensorStatus = "";
  var sensorValue = "";

  var captureSensorData = false;

  console.log(a + " " + c);
  I2C1.writeTo(a, c);

  setTimeout(function () {
    d = I2C1.readFrom(a, 9);

    if (d.length > 0) {
      var dContent = d[0];

      switch (dContent) {
        case 1:
          //console.log("Success");
          sensorStatus = 1;
          captureSensorData = true;
          break;
        case 255:
          sensorStatus = 255;
          break;
        case 254:
          sensorStatus = 254;
          break;
        case 2:
          sensorStatus = 2;
          break;
      }

      if (captureSensorData === true) {
        for (i = 1; i < d.length; i++) {
          //console.log(i + " = " + d[i]);
          sensorValue += String.fromCharCode(d[i]);
        }
        console.log(sensorValue); //<-----Outputs the value correctly
      }
    }

    captureSensorData = false;

    return sensorValue;
    //console.log(sensorValue);
  }, w);
};

var restemp = new Sensor("RES TEMP", "temp", 77);
var ph = new Sensor("PH", "ph", 78);
var ec = new Sensor("EC", "ec", 99);

function getAllSensorData() {
  resTempVal = restemp.takeReading();
  return resTempVal;
}

setInterval(function () {
  console.log("Taking Reading: ");
  getAllSensorData();
}, 5000);

I don't really understand - so you're saying that the console.log(sensorValue) is actually correct, when it gets to that point?

Isn't 77 r coming from console.log(a + " " + c);?

Oh crap, ya its coming from console.log(a + " " + c); I forgot to comment that out.

I'm getting undefined for resTempVal and undefined outputs before console.log(resTempVal); So, i'm assuming there's a small delay while taking the sensor reading and the variable resTempVal isn't set. Is there a way to wait until resTempVal gets set before I continue?

code:

Sensor.prototype.takeReading = function() {
  var a = this.sensorAddress;
  var c = this.cmdTable.Reading.R.cmd;
  var w = this.cmdTable.Reading.R.wait;

  var d = "";
  var sensorStatus = "";
  var sensorValue = "";

  var captureSensorData = false;

  I2C1.writeTo(a, c);

  setTimeout(function () {
    d = I2C1.readFrom(a, 9);

    if (d.length > 0) {
      var dContent = d[0];

      switch (dContent) {
        case 1:
          sensorStatus = 1;
          captureSensorData = true;
          break;
        case 255:
          sensorStatus = 255;
          break;
        case 254:
          sensorStatus = 254;
          break;
        case 2:
          sensorStatus = 2;
          break;
      }

      if (captureSensorData === true) {
        for (i = 1; i < d.length; i++) {
          sensorValue += String.fromCharCode(d[i]);
        }
      }

      captureSensorData = false;
      console.log(sensorValue); //<-- I get output
      return sensorValue;
    }
  }, w);
};

var restemp = new Sensor("RES TEMP", "temp", 77);
var ph = new Sensor("PH", "ph", 78);
var ec = new Sensor("EC", "ec", 99);

function getAllSensorData() {
  resTempVal = restemp.takeReading();
  console.log(resTempVal); //<-- undefined
}

setInterval(function () {
  console.log("Taking Reading: ");
  getAllSensorData();
}, 5000);

As you say, your problem is that takeReading returns immediately - even though it sets a timeout using setTimeout.

This is classic JS though. You need to use a callback function:

Sensor.prototype.takeReading = function(callback) {
  // ...
  setTimeout(function () {
    // ...
    callback(sensorValue);
  }, w);
};


function getAllSensorData() {
  restemp.takeReading(function(resTempVal)­ {
    console.log(resTempVal);
  });
}

@Gordon. That did the trick. Thanks