Do you want to show the absolute time on the x axis or something else? In order to show the actual time, you need to set the x axis formatting to absolute time and wire the start time and increment to a property node of the chart. Look at the shipping example called Real-time Chart.
I don't understand your comment about the plot showing a different value than the digital display. The only example you posted with a digital display has a numeric array indicator and it will show the most recent value acquired for each channel. The way you had it wired, it has to display the same as the last points plotted on the chart. If you've made some significant changes to your program, you might want to post what you've done now.
