I realise that this must be very simple, however I can't seem to find how to subtract two values. I've basically got an input, and output voltage reading from a daq board, that displays one value being outputted from the computer, and another value being read into it. All I need to do is subtract one from another, and have this value displayed in the table, with the other two values. After this is achieved, I also require a function to add a gain (to the previous difference or "error") of which the number can be changed whenever required.
Thanks a lot, I've tried to search, but can't find anything specifically the same as my question.
