Before you say yes... I am using a crio device in scan-mode interface. The values that the scan mode returns are in double-precision floating point. Apparently I am supposed to be able to choose between double-precision floating point ("calibrated") and fixed-point ("uncalibrated") data, but this functionality appears to be exclusive to the fpga interface and is not available with the scan engine. Both data types are 64-bits per value, so when it comes to size-on-disk, either way is basically the same anyways. The system is continuously recording 13 channels of double-precision floating point at 200Hz. Using the binary file write method, I have measured this to be about 92 MB/hr to disk. (over 120mb/hr with tdms and a lot more for write to spreadsheet) Simply put, this 92 mb/hr rate is just too much data to disk on this system. The modules I am recording from, the 9236, 9237, and 9215 c-series modules, have 24-bit ADCs or less. Does this mean I don't need 64 bits to represent the number and maintain the same accuracy? Can I coerce/cast the double-precision floating point values I am receiving from the scan engine i/o variables to another, smaller data type like single-precision floating point and still maintain the same accuracy? Message Edited by rex1030 on 08-27-2009 04:19 PM

Nickerbocker wrote: between noise and hardware accuracy, i doubt it makes much of a difference. You can test it by looking at the difference between a DBL and DBL converted to SGL. But I support the hint from Nickerbocker. I do not think it will make difference