Chart Tick and Format


i would like to understand something about the chart properties.

I need to change the format string, as im trying to allow the costumer to adjust the X Axes Tick, but when i change the tick size from the following script, i get the x axes to be just an incremetal number.
I would like to know how to access the propery “format”.

As im already here, i ask you if there is any way, sarting from an ammount of elapsed seconds, to show H:mm:ss, but letting the hours growing, so when the timestamp reach the 23:59:59 , it will keep going like to 36:00:00 , without restarting from 00:00:00.