Electricity + Control May 2015

ANALYTICAL INSTRUMENTATION

ROUND UP

High availability and functional safety up to SIL3

The requirements on operational and safety-related circuits in plants are continuously growing which also affect the technical require- ments on components. Often, functional safety can only be increased with much effort and at the expense of availability. Proving that high safety standards and high availability can go hand in hand, Knick has introduced ProLine P 22400 passive standard signal isolators certified for applications with a SIL3 safety integrity level according to EN 61508.The passive isolator’s safety functional- ity is the highly precise, linear transmission of 4...20 mA signals with a low transmission error of 0,08 % full scale. A high level of func- tional safety can be achieved even in single-channel structure and without diagnostics. For instance, sensors and actuators in safety circuits can be connected directly, requiring no elaborate evaluation equipment for redundant structures. The isolator’s robust design ensures excellent availability with a mean time between failures of 965 years. Thanks to loop-powered operation, it contains fewer parts than devices with an auxiliary power unit and the total failure rate is decreased. Furthermore, it is mechanically stable, approved for marine applications, resistant against electromagnetic interfer- ences, and boasts protection against electric shocks up to 600Vac/dc through reinforced insulation.The test voltage during routine testing is 5,4 kVac. ProLine P 22400 is suitable for ambient temperatures between -40 and 85 °C. Knick provides a five-year warranty for all ProLine devices. Mecosa is the sole agent for Knick ElektronischeMessgeräte in Southern Africa. Enquiries:Tel. 011 257 6100 or email measure@mecosa.co.za