Multiple value axes on XY chart

All our charts which have valueAxis can have multiple instances of this axis. This means you can have any number of value axes on XY chart and even radar chart can have several value axes. You just need to create additional ValueAxis (use position="right" if you want to place it on the right), then assign some graphs to it:

// first vertical value axis
var yAxis = new AmCharts.ValueAxis();
yAxis.position = "left";
chart.addValueAxis(yAxis);

// second vertical value axis
var yAxis2 = new AmCharts.ValueAxis();
yAxis2.position = "left"; // set this to "right" if you want it on the right
yAxis2.offset = 30;
chart.addValueAxis(yAxis2);

// GRAPHS
// graph #1
var graph1 = new AmCharts.AmGraph();
graph1.lineColor = "#FF6600";
graph1.xField = "ax";
graph1.yField = "ay";
chart.addGraph(graph1);

// graph #2
var graph2 = new AmCharts.AmGraph();
graph2.lineColor = "#FCD202";
graph2.xField = "bx";
graph2.yField = "by";
graph2.yAxis = yAxis2; // we need to assign at least one graph to a value axis or it's not shown
chart.addGraph(graph2);

You can have multiple vertical and horizontal value axes. Use valueAxis.offset property to separate value axes if they are on the same side (this property won't work on radar charts).