Level sensor is approved for SIL2 safety loops

Paul Boughton
The modernised, digital E3 Modulevel from Magnetrol is an advanced, intrinsically safe, two-wire instrument utilising the buoyancy principle to detect and convert liquid level changes into a stable output signal. The new E3 Modulevel benefits from updated packaging, increased functionality, diagnostics and the capability to configure rather than calibrate the transmitter. The E3 Modulevel supports Foundation fieldbus, Hart, AMS and FDT/Pactware communication protocols.
While the cast iron enclosure used on the previous electronic Modulevel design was large and unwieldy, the adapted dual-compartment Eclipse enclosure used on the E3 is modern, lightweight and ergonomic. This enclosure contains the wiring and analogue and digital boards. The LVDT (linear variable differential transformer) is housed separately, adjacent to the enclosure, and the two are joined by a flame path adaptor. The complete, explosion-proof housing assembly is offered in both cast aluminium and stainless steel.
The E3 Modulevel is claimed to be the only displacer transmitter on the market with a SFF of 92.3 per cent, making it suitable for SIL2 safety loops. The additional diagnostic tools allow users to integrate this transmitter into highly demanding safety instrument loops (Exida endorsed). The E3 withstands process temperatures and pressures up to +315 degrees C and 355bar, handles liquids with a specific gravity as low as 0.23 and up to 2.2, and liquid/liquid interfaces with a minimum density difference of 0.10kg/dm3. By simply entering two process variables (temperature and SG) the E3 Modulevel is ready for service.
Unlike the traditional torque tube design, the E3 Modulevel uses a precision range spring. The spring reduces the friction of moving parts (only one linear motion) and provides natural damping. The result is a more reliable and stable output, even when the liquid surface is turbulent. Because an LVDT offers twice the travel of a typical RVDT (rotatable variable differential transformer), the accuracy/linearity of a spring-operated displacer transmitter is said to be superior to traditional torque tube designs.
For more information, visit www.magnetrol.com

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