What am I seeing ?

[TundraJoe]

I've recently updated my firmware and have been downloading DATLOG data. I assume that the airspeed on the EFIS 100 is indicated airspeed, taken from the pitot static system. During slow flight , my screen shows 52 mph--but when I download the data, the Excel spreadsheet shows speeds of almost 10 mph less ! ( I assume the same differential exists for normal flight speeds, I just didn't pay attention to my screen speeds at normal cruise--was closely watching at near stall )
Thanks

 

[dynonsupport]

So the IAS in the log is always in knots. If you're comparing that with the speed you're seeing in MPH, then you should expect them to be 15% different (100 knots is 115 mph).