Strange math-problem with LabVIEW 7.1

Hello!
I am using LabVIEW 7.1 and I came to this strange math-problem. Could it be that it is a problem of LabVIEW 7.1?
Ok try this with LabVIEW 7.1:
open a new VI
place a subtract-VI (pallet numerical) on the block diagram and try to subtract 0.2 from 1.6
place a less-VI (pallet compare) on the block diagram and wire a numerical constant 1.4 to input x
wire the result of the subtraction to input y of the comparison
place an LED to the output of the comparison
and start this.
What does it say?
The LED should turn on and this means here that 1.4 would be less than 1.4 .
But I would have expected that 1.4 is not less than 1.4 .
This works also if you add or subtract upto 0.2 to/from the values 1.4 and 1.6 (or equivalent with 0.2) .
If you change the inputs of the comparison then the result is as expected and 1.4 is reported not to be less than 1.4 .
If you compare two constants with the same value 1.4 you will not get the same strange result.
Does anybody have an explanation for this?
Espelkamper

Hello,
For floating point math: Rounding to multiples of 0.1 is problematic as
those numbers are infinite fractions in base2 representation...
So maybe you should change your numbers to integers using fixed point math. If all your input values are in the range of 1.4 to 1.8 you can multiply by 10000 and round to next integer. Then do your comparison on that integer (there's also an 'InRange' function in the comparison palette).
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
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