I was working with a model of a robot arm type thing, and wanted to use an IK constraint with an empty as the target to assist in posing. I abandoned the idea because: The IK constraint seems to run over any kind of angle limits I put on the bones it affects. Though, that was back in 2.80, or maybe 2.79. On the chance that it hasn't changed, what can I do?
Select a bone in an IK armature in Pose Mode. Then click the Bone Properties tab in the Properties window and scroll down to Inverse Kinematics. There you can lock rotation around certain axes or check a box per axis to limit the rotation around this axis, and enter the desired degree values. There are also fields related to Stretch and Stiffness which can help control the movement of the IK armature.
Another thing than might cause similar issues: Normally one bone in the armature has the IK Constraint on it. This constraint targets the Armature and a Bone to follow (hand.L in the picture). Make sure this target bone is not parented to the armature. Select it in Edit Mode, press Alt + P and choose Clear Parent.