Hi Amit,
I went through your code and I found that you didn't select channel to be measured, before calling the StartSingleMeasurement() method.
For this please use the CreateSampleGroup() or SelectSampleGroup() method. You can find more info on right click of the component-> Help on component -> Typical Usage page.
CreateSampleGroup() - is used for the runtime preparation of the sample group, while SelectSampleGroup() is used to select sample group from prepared in the Property tab ->Static sample group.
Best regards
Jiri