Protected Excel Sheet With Macro Changes

I have an Excel worksheet that needs to be protected to keep users from making changes. This worksheet is reading in data from a linked program and then outputting this information into the spreadsheet by way of macros. If data is out of bounds I also change the fill color of a cell to RED. It works great without protection but once protected causes an error in the macro because it is not allowed to change the spreadsheet. Is there a way to give authority to the macros but not the keyboarduser?