In-Situ Win-Situ 2000 Operators Manual - Manual (Page 45)

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APPENDIX
decades due to machine floating-point roundoff, but the actual time
value at which any given data point was taken will be reported
accurately in the data file to the fourth decimal place.
The interval between measurements will continually lengthen, but your
specified Measurement Interval serves as a “linearization” value such
that the interval between measurements will never become greater than
this value. For example, with a Measurement Interval of 20 minutes, the
device’s sampling interval lengthens until a 20 minute interval is
reached, then it begins to sample linearly from that time on at 20-
minute intervals.
In a true logarithmic sampling scheme, the interval between points
would be infinitely short at time t=0 (the start of the test), which implies
infinitely rapid sampling. The device cannot sample faster than once
every 300 milliseconds (0.3 seconds). Thus, a linear sampling rate of
one point each 300 milliseconds occurs for the first 6 seconds into the
test, then the logarithmic decline begins.