ingParam('combine');
  var keys = sortedKeys(results);
  for (var i = 0; i < keys.length; i++) {
    var key = keys[i];
    var name = key;
    var values = [results[key]];
    var unit = units[key];
    if (combine.indexOf(key) >= 0) {
      i--;
      name = combine;
      values = [];
      var combined_keys = combine.split(',');
      for (var j = 0; j < combined_keys.length; j++) {
        values.push(results[combined_keys[j]]);
        keys.remove(combined_keys[j]);
      }
    }
    displayChart(hz, 