Thanks again for all the detail.
Have now changed the software serial stuff over to Serial3 as you suggested.
Am still working on saving the data to a memory stick plugged into the FTDI module.
I am using a MAX232ACPE chip to convert to serial when communicating with the DMM, would I also need to use a MAX232 chip when communicating between the Arduino and FTDI aswell?
I am sending commands to the DMM and receiving results back in the Serial monitor, I just want to save these results exactly as they appear in the serial monitor onto a USB/memory stick as a txt file or ideally an Excel document.
Thanks,