How to limit movement of a IK-chain (armature) to one plane? I build a Zig-Zag-mechanic from a bone chain and enabled Inverse Kinematics for
the first bone and the whole chain.
When contracted it should look like this: VVVVVVV
Currently it is a straight line of bones like this: ---------------
Now the fun part ;)

How can I force the bones to always build this ZigZag-Pattern if the IK-enabled bone is moved directly towards the opposite of the chain?
How can I force the bone chain into one plane of movement?
How can I force the bone chain to build a half circle if the IK-enabled
bone is not directly moved towards the end of the chain?
The movement of the IK-enabled bone always is in the same plane as the rest
of the bones.
I tried "Limit rotation" but this does not work for me (which either could
mean, that I did something wrong or "Limit rotation" is the wrong tool.

How can I acchieve what I want to do?
The IK constraint generally ignores other constraints, so using limit constraints won't work.

However each bone has its own IK settings on their properties panel that allow you to limit rotations etc, for more information see https://docs.blender.org/manual/en/dev/rigging/armatures/posing/bone_constraints/inverse_kinematics/introduction.html#bone-ik-panel