How can I treat a missing value in a locked column as zero?

[#1]

JMP 17.2.0

I came across this thread, which was a perfect solution to calculating a time difference between rows, using the formula below in a Formula Column.

Col Cumulative Sum(Dif(:Time))

However, I am getting a blank/missing item in the first cell of the Formula Column, which then causes my resulting graph to not start at zero.

Right now, I'm getting around it by inserting a row at the top of the data table with the same time, which results in Row 2 providing a zero-point.

Is there a way to treat the missing value as zero in a locked column? Or better yet, is there an edit I can make to the formula to form a T0 point?

Thanks in advance!

[#2 · Accepted solution]

You can for example add if statement

If(Row() == 1,
	0
,
	Col Cumulative Sum(Dif(:Time))
);

[#3]

Beautiful, thank you! The below worked perfectly.