Subtracting 90 minutes from a time set in a data item

[MolToward]

Hi,

I'm trying to add a step to subtract 90 minutes from a time acquired in a BP data item.

I've tried the function MakeTime but it doesn't work.

Just to give a better idea, my current process is -> Time is received as a text item -> step to convert this ToTime. I've tried to add this MakeTime function before the conversion to time but with no luck.

Please help?

 

[MolToward]

Edit: I've now worked it out. We have to separate the hour from the minute, remove the colon in between, convert the two items to numbers then use MakeTime([Hour], [Minutes] - 90, 0)