Question on constraints

[[De...]]

I have a plane that is datum A on the bottom face of a part. There is a parallel plane in the bottom of some slots with a surface profile callout back to A. no other datums are called out. I am having some repeatability issues. As I was looking at some info in the cookbook, it said that for my example to allow translation in X and Y and Rotation around Z. so the A datum plane is in primary secondary and tertiary currently. with no "Constraints" when looking at the constraints available, I have X, Y, Z, and Normal Vector. I guess my 2 questions are as follows

1, putting the datum a in all three datum locations, is that the right way to do this, and if not, how should I do it?
2. What does constrain to normal vector actual mean in laymen's terms? I am struggling to grasp this and just need someone to explain it to me in a way I can grasp.

[[Ma...]]

For profile callout you can fill only first one to gain that freedom. It will make it as primary and fixed in it's vector height - so if it's plane in Z vector, then every height ( Z nominals ) are fixed from that plane A - X,Y and Z rotation are free so you get bestfit like that.

I am not sure what and where you want to check those constraints. Is it on FF?

[[No...]]

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Constrain to normal vector means that the actual values of the plane's angles (A1/A2) will exactly match the nominal angles.
But I don't understand why you would want to check those for a profile measurement.

[[De...]]

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This helps me understand the constrain to normal vector portion of the question. Thanks for that insight.

[[De...]]

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In the profile window in the datums is where I was looking. I inherited this program from the guy who left. He programmed the datum A as primary secondary and tertiary. Its not repeating. I don't truely understand constraints all that well, and if that could help me. I will try only having Primary datum filled in.

[[Ke...]]

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Check the filter/outlier settings, as well as the actual form of the Features that are being used... see if those show any of the same instability as the Surface Profile result.. depending on your parts geometry, and the stability of the Base Alignment, it may be helpful to loop the Base Alignmnet and/or use reference features to repeatably locate the Features that you are using.