anchor or semi anchor

could you tell me about the difference between anchor and semi anchor really;

when we anchor a point maybe there is ver large moment at point but when we
change it to semi anchor the moment will be eliminate;
i would like to say that actually when the pipe going to rotate , there is a time that pipe saddle facing with guide support and after that we will have moment but when we are modeling semi anchor(guide+stop) it won't be counted. how could i model it correctly?

A "guide+stop" is not the same thing as an "anchor".

An "anchor" restrains the specified node point against movement in all six degrees of freedom.

A "guide" is a horizontal translational restraint perpendicular to the pipe axis. So this restrains movement in a single degree of freedom (assuming the pipe is in "X" or "Z").

A "stop" is a horizontal translational restraint aligned axially with the pipe. So this restrains movement in a single degree of freedom.

If you can't use an anchor, you need to restrain the appropriate DOFs individually.