heyas; well, the problem is, that when ik is on, the rotation limits are ignored. i thought i heard/read somewhere that had been fixed in... p5, i think. but i'm not sure it is still fixed. or else i was dreaming. i don't see how erc can help you. what dial are you going to slave to what to make it not twist as you use ik? you could try setting the twist dial to useLimits 4 instead of 0... then see if ik obeys the limits.