VBA: Add time since last input

Hello.

I am making an excel workbook where operators should make input with buttons etc when an event has occured with the machine they´re running.
I have a solution which enters the time stamp for when they press the button but I'd like the function to also add the time since last input in another column.
The thing is that I have several operators who work on different machines so the time must be counted based on which operators(machine) which had an event.

The function I look for should look in column D if the machine already have inputs earlier the current day. If it finds an input the code should count the time difference between now and the last input. If it doesn't find any earlier data it should enter 00:00:00.
I have attached a small example how the sheet looks like where the data is stored today.
I need some support on how to do the coding to make this work.

Anyone who can help with this tricky question.

Kind regards
Anders

Here is a full solution. It includes the custom time difference function.

Please Login or Register  to view this content.

Perfect!! I am able to understand how you hade done it and can alter it to fitt the exact function I need.
After the script have run, I'd like to sort based on column A and b. I have copied your code:

Please Login or Register  to view this content.

How to I alter the sort to sort by date and then time for input? (Column A and B)

Here is the main function with the updated sort

Please Login or Register  to view this content.