Endress+Hauser Deltabar FMD72 Electronic Differential Pressure measurement system

The Deltabar FMD72 Electronic Differential Pressure measurement system uses two pressure sensor modules connected electronically to a single transmitter - thus eliminating the need for impulse lines or capillaries and their related issues of icing up, clogging, leaky taps, dry/wet leg inconsistencies and problems with temperature changes.

Ambient temperature changes cause measurement drift in traditional capillary systems, but up to 95% of this drift can be eliminated with the FMD72. The company claims that, in addition to eliminating operational and maintenance problems, the FMD72 responds up to 10 times faster than traditional impulse and capillary systems, is easier and less expensive to install and does not require heat tracing.

One sensor module measures the hydrostatic (high pressure), the second sensor measures the head pressure (low pressure) and the transmitter calculates the differential pressure. These measured values can be used to calculate the level, volume or mass of liquids in pressurised tanks.

The sensors connect to the transmitter module via industry-standard, colour-coded twisted pair cable and have NEMA 4X/6P (IP66/IP68) watertight housings and connections. The transmitter can be located away from the sensors in areas safe and convenient for personnel. The system meets ATEX, IEC Ex, CSA and FM specifications for use in hazardous areas including Zones 0, 1 and 2 and Division 1 and 2.

The transmitter outputs differential pressure, head pressure and temperature via 4-20 mA with HART. The sensors have 0.075% accuracy over a measuring range of 15 to 150 psi and work in process temperatures from -40 to +125°C. Accuracy of the entire system - two sensors and the transmitter - is 0.1%.

The system has built-in diagnostics for continuous health indication via HART. Operators can access HART data via Endress+Hauser’s FieldCare software or Field Xpert PDA.