IK direspects limit rotation

Hello all, I am trying to make a robotic arm rig, like you would find in a car factory.
and I am having trouble because IK does not seem to respect limit rotation.
If I add an IK constraint to every bone in the chain, and a limit rotation
it does not limit it’s rotation at all.
same thing happen with just the first bone having an IK constraint.
Edit, I fixed this by adding a Platfom Bone which stay under arm target,
and by shortening the IK chain.
to allow constraint all these bone have duplictaes that copy them using Track To
so I can now apply all the Constraints I want
can’t remove the pic, sorry