In many instances measurement equipment which makes contact with the media or product provides inaccurate results owing to corrosion, mechanical damage or a build‐up of the monitored production on the sensor. In view of the possible deleterious effects it is better to operate a non‐contact method of monitoring, especially in the food and pharmaceutical industries. This produces greater reliability coupled with lower maintenance. The infinite possibilities of non‐contact options require expertise in inductive, capacitative, photoelectric, infrared and ultrasonic measurement and control technology.