Hi Paul,
As far as I understand the query, you have a chart and want to update it based on a user input Start and End Date on some action (button click).
function applyDates() {
var qObj=PITagi5Chart.getQueryObject();
qObj.setStartDate(sDate);
qObj.setEndDate(eDate);
PITagi5Chart.update(true);
}
The above code should refresh the chart with data for the applied date range. I believe this is what you are also trying and I don't see reasons for the code to not work.
Can you please post the code snippet or scenario you are trying.. may be your html page, so that we can have a further look and get back with solutions.
Also please do mention the SAP UI5 version.
Thanks and Best Regards,
Ria