Behaviour of Ironless Inductive Position Sensors in Close Proximity to Each Other

Safety critical systems like the collimators of the Large Hadron Collider require transducers which are immune to interference from their surroundings. The ironless inductive position sensor is used to measure the position of collimator jaws with respect to the beam and is designed to be immune to external DC or slowly changing magnetic fields. In this paper we investigate whether frequency separation is required when multiple ironless inductive position sensors are used and whether two or more sensors at the same frequency results in cross-talk. Numerical simulations and experiments are conducted to study the magnetic field behaviour of the sensors, their interference with each other and the impact of this interference on the position reading. Finally, this paper defines guidelines on safe operation of the ironless inductive position sensor in the aforementioned conditions.