Profile using FCF and Secondary Alignment having different outputs

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Profile Evaluation using FCF and Secondary Alignment.pdf
I am evaluating a profile using a FCF and Secondary Alignment and am coming up with drastically different outputs.

Datum C is the back wall of part (pink)
Datum B is the 10.00mm diameter arc
Datum A is the top surface

Using the FCF, Datum C is primary, Datum B secondary, and Datum A tertiary the profile output is .073mm

Using the Secondary alignment, using the same datum structure, the output is .165mm

Using the FCF the profile is in tolerance but with the secondary alignment out of tolerance.

In the upper-level drawing the profile is only evaluated to Datum A.

My finding is the use of the secondary alignment represents the true relationship of the profile in respect to its location from Datum A.

My question is why does the FCF seem to disregard the profile relationship to Datum A? This is problematic when trusting the software to do its job.

Please see attached pdf.Profile Evaluation using FCF and Secondary Alignment.pdf

[[Ro...]]

Your Z origin should be -B- in your second alignment, not -A-. A is only clocking the part. -B- is the actual Z origin. Your first alignment is using -B- as the origin, thus the different results.

[[Mi...]]

Also,

If ASME and your calypso is setup properly, FCF is going to be setting the Datums to OTE and applying ISO 5459.

Secondary alignments do not do this by default.

[[To...]]

Thank you for your response. The print FCF calls out the profile to CBA. If the Z location is critical should the datum sequence, be changed to ABC?

[[Er...]]

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This looks like a design question. CAB may be more appropiate.
The ASME Y14.5-2009 Section 4 on Datum Reference Planes may help you.