44 n SENSORS AND ENCODERS July/August 2026 www.drivesncontrols.com How to adapt to revised standard for sensors in sterile areas The EU’s GMP (Good Manufacturing Practice) Directive requires that sterile medicinal products and medical devices must be packaged free from contamination. The updated Annex 1 effective since the end of August 2024 means that this now applies not only to parts that come into direct or indirect contact with products, but also to all components that may disrupt “first air” – such as sensors positioned above sterile components. Various challenges and opportunities arise for the use of sensors in pharmaceutical production and packaging, depending on their type. The new Annex 1 requirements make the careful selection and integration of sensor technologies essential. Hygienic, flexibly mountable stainless-steel sensors can help you to comply with the requirements safely and efficiently. First air The position and type of sensors and reflectors used, play a key role in complying with the new Annex 1 requirements. Sensors or reflectors mounted above the product are considered contact parts that interrupt first air. They must be sterilised by SIP (sterilisation in place) or autoclaving procedures. In practice, ultrasonic sensors for filling level measurement and retroreflective photoelectric sensors with reflectors above the product are often used because they offer the necessary operating ranges. These designs are now critical: reflectors and ultrasonic sensors often cannot withstand the high temperatures and conditions of sterilisation. Even if they are technically suitable for sterilisation, this would involve considerable additional work and costs because the sensors and reflectors would have to be removed for autoclaving. Modern optical sensors based on the ToF (time of flight) principle– such as Leuze’s ODT55CL1-2M – provide significant advantages in relation to Annex 1. Thanks to their long operating range, they can be mounted at the side of, or underneath, the product and at a considerable distance from it. As a result, they have no direct, indirect or first-air interrupting contact with the sterile product they detect – for example, a stopper plug – and therefore do not need to be sterilised. Compact designs, such as those offered by 53C and 55C sensors in stainless-steel housings, are also an advantage, because space is often limited in pharmaceutical plants. Where sensors allow measurement values to be evaluated via IO-Link, operators also benefit from additional process data. This makes control and verification in accordance with Annex 1 easier. The new Annex 1 requirements make the careful selection and integration of sensors essential. Hygienic, flexibly mountable stainless-steel sensors can help to implement the specifications safely and efficiently. n In 2024, The European Union updated its GMP guidelines on the manufacture of medicinal products in sterile environments. The modernised legislation has implications for sensing technologies, as Sven Schillinger, global product manager at Leuze electronic, explains. In this application, sensors are used to detect plugs on a conveyor. In accordance with Annex 1, reflectors should no longer be placed above the track due to the need to sterilise first-air-interrupting components. Because the colours of the stoppers can vary, it is necessary to ensure that dark materials can be detected. Triangulation-based reflective photoelectric sensors would not have sufficient range to detect dark plugs, so time-of-flight laser sensors with a range of up to 2m and reliable detection of all colours, have been used instead.
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