javascriptajaxvbscriptgoogle-gaugesewon

Google Gauge chart not displaying


I want to create and display a google gauge chart on a webpage for a remote monitoring program I am developing. I am using an eWON Flexy 201 to do this. I am just having trouble getting the gauge to display on the webpage.

Basically what I have to do is use a form of VBScript on the server to grab the oil temperature and return that value to the gauge to display the temperature. I have been able to return that value to the page in various ways correctly, however I am having trouble displaying and updating the gauge every second like I want to.

In the current script I am receiving no errors in the console, however nothing is rendering. I get just a blank space where the gauge should appear.

<script type='text/javascript'>
  google.load('visualization', '1', {packages:['gauge']});
  google.setOnLoadCallback(drawChart);
function drawChart() {

var x = '<%#TagSSI,Target_Pressure_Setting%>';


var data = new google.visualization.DataTable([
  ['Label', 'Value'],
  ['Oil Temp', x],
]);
var options = {
  width: 450, height: 240,
  greenFrom: 100, greenTo: 150,
  redFrom: 275, redTo: 325,
  yellowFrom:225, yellowTo: 275,
  minorTicks: 5,
  max: 350
};

var chart = new google.visualization.Gauge(document.getElementById('chart_div'));

function refreshData () {
    var json = $.ajax({
        url: 'gauge.shtm', // make this url point to the data file
        dataType: 'number',
        async: true 
    }).responseText;
    //alert(json)

    data = new google.visualization.DataTable(json);

    chart.draw(data, options);
}

refreshData();
setInterval(refreshData, 1000);
}

</script>

and here is the gauge.shtm file

<%#TagSSI,Oil_Temp%>

Solution

  • I figured out my problem. I'm not particularly sure what was going wrong with the answer @Rohit416was giving me, however upon more searching on the web I came across a solution and amended it to my needs.

    Here is the solution that ended up working for me

    <script type="text/javascript">
    
          google.setOnLoadCallback(drawChart);
    
          function drawChart() {
    
            var data = google.visualization.arrayToDataTable([
              ['Label', 'Value'],
              ['Oil', 80],
            ]);
    
            var options = {
              width: 400, height: 140,
              redFrom: 275, redTo: 350,
              yellowFrom:200, yellowTo: 275,
              greenFrom: 100, greenTo: 150,
              minorTicks: 5,
              max: 350
            };
    
            var chart = new google.visualization.Gauge(document.getElementById('chart_div'));
            chart.draw(data, options);
    
           function getData () {
            $.ajax({
                url: 'oil.shtm',
                success: function (response) {
                    data.setValue(0, 1, response);
                    chart.draw(data, options);
                    setTimeout(getData, 1000);
    
                }
            });
        }
        getData();
    }
    google.load('visualization', '1', {packages: ['gauge'], callback: drawChart});
    

    and my oil.shtm file is as follows

    This successfully updates my gauge every second, and I tested this method with multiple gauges at once and it works as well.