Red Datum

[Slimvinn]

I have a datum assigned to a feature. When I TP to a feature and call out the primary and secondary datums and hit exit my secondary shows up red.

Is there a reason why they show up red? I am assuming that it's because it's OOT.

[Mike Johnston]

I have never had any luck with using 2nd and 3rd datums when calculating position. The position never seems to come out right. I usually only dimension the TP of the feature and then do any bonus calculations manually. V. 3.7MR2... Seems that it may be a bug...

Mike

[Paul Sarrach]

I have never had a datum OOT

But if I understand you correctly it should show out. your primary datum is being zero out in two axis. The secondary is being zero'ed out in only one axis ( it is being rotated to) so the other axis is free, and what you are seeing is the distanced from each other from nominal. You get a tolerance for that dimension.

[craiger_ny]

Here we go again. Check this out: read this whole thread

That was a good thread that addresses exactly what you have going on.

Craig

[RussL]

I don't have the time to read the other thread, so maybe I'm way off base but...
I believe you are correct, the datum would be red if it is out of tolerance (diametrically).
Like many I used to have problems with TP also, but most of the problems went away when I started checking the deviation perpto centerline box.
I use multiple datums with and without MMC.
I had checked the numbers I was getting a while back and they were OK,
I am using V3.7 MR-2.