Reliable signal transmission in sensitive processes

SIL-certified signal converters for areas with a potentially explosive atmosphere are the newest addition to the Weidmüller solution package for safety-related signal circuits in the process industries and energy technology.

Head of industry management for the process area, Stefan Kappel, and product manager, Sascha Dreifert, explain the backgrounds of the extended offering in an interview.

WIN! Increasing requirements concerning functional safety are among the clearly identifiable industry trends. What is Weidmüller's position on this?

Kappel: Functional safety has become a focal point in recent years, above all in the process industry. The protection of people, environment and machine is a top priority. Last but not least, the avoidance of faults and errors – or, in the worst case, even complete machine shutdown – makes a significant contribution to increased productivity, so that functional safety constitutes a major competitive factor. As a partner of Industrial Connectivity, we offer in-depth expert knowledge in this special area. Our experienced industry managers

Funktionale Sicherheit rückt in der Prozessindustrie und Energietechnik vermehrt in den Fokus

advise plant operators around the world on the topic of safety in sensitive processes and support them in the selection of suitable solutions for the observance of functional safety in compliance with EN 61508.

WIN! What distinguishes the solutions for safety-oriented applications that Weidmüller provides to its customers?

Kappel: We support the trend away from pure operational dependability and towards the use of development-certified SIL components. In plain language this means: We do not leave it to our customers to document the suitability of the products used in order to extrapolate an SIL classification on this basis. In point of fact, as a manufacturer, we exclude risks from the outset by offering certifications based on FMEDA (Failure Modes, Effects and Diagnostic Analysis) analyses.

In this context, components establish their reliability in quantitative terms – both with regard to systematic and random errors. In order for this type of preventative approach to become general practice, NAMUR (an international user association of automation technology in process industries) has also provided an appropriate recommendation.

WIN! What properties make the ACT20X signal converter stand out in practice?

Dreifert: The safety functions in explosive zones, e.g. the switching on and off of aggregates, the surveillance of actuators or the monitoring of temperature and pressure, require signal converters that have an SIL certification. Our ACT20X is used flexibly in both intrinsic and safety-related signal circuits in the global process

industry. Behind the wide range of possible applications is our practically-oriented development process, which was accompanied from the outset by the independent test organisation, exida. Based on a full assessment appraisal in accordance with the requirements of IEC 61508, exida was able to confirm that the ACT20X has unrestricted SIL-2/SIL-3 classification.

WIN! How do the signal converters fit in the Weidmüller solution package for functional safety?

Dreifert: This is most clearly illustrated by an application example such as the overfill protection on oil tanks. Here, together with our SAFESERIES safety relay and surge protective devices from the VARITECTOR program that are also SIL certified, the ACT20X signal converter allows a complete safety

Weidmüller Lösungspaket für sicherheitsgerichtete Applikationen: SIL-zertifizierte Signalwandler, Sicherheitsrelais und Überspannungsschutzgeräte

circuit to be set up according to SIL 3: from safe receipt and transfer of the signals on the filling level sensor through safety-oriented shutdown if conditions become critical up to the setting up of protective measures for long signalling pathways.