Endress+Hauser PMD55B Deltabar Differential Pressure Transmitter

Endress+Hauser PMD55B Deltabar differential pressure transmitter

The Endress+Hauser PMD55B is a digital differential pressure transmitter with a metallic process membrane, built for differential pressure, level and flow measurement in liquids and gases. It belongs to the newer B generation of Deltabar devices: HART or PROFINET over Ethernet-APL, optional Bluetooth, a large display with wizard-based commissioning, and optional Heartbeat Technology for verification and monitoring. Seven Star LLC supplies the PMD55B in Oman and the GCC as an independent supplier based in Muscat.

The datasheet lists differential ranges up to 40 bar (600 psi), static pressures up to 250 bar (3 750 psi) and reference accuracy up to ±0.055 %, so the PMD55B is positioned as the high-performance transmitter in the Deltabar line for orifice flow, filter monitoring and hydrostatic level in pressurised vessels.

PMD55B technical specifications

Data are from the Endress+Hauser Technical Information for the Deltabar PMD55B. Pressure limits on a given device depend on the lowest-rated element of the ordered process connection and seal.

How the PMD55B measures differential pressure

Both process pressures act on separate metallic membranes. The fill fluid transmits each pressure to the middle diaphragm of a silicon measuring element, which deflects in proportion to the difference p1 minus p2, and a resistance bridge turns that deflection into an electrical signal. The cell body and side flanges are 316L, with cast 316/316L or, on coplanar versions, Super Duplex side flanges for seawater service. Vent valves are built in.

For flow the PMD55B reads the differential pressure across an orifice plate or pitot tube, and its low-flow cut-off parameter (5 % by default in square root mode) holds the output at zero near no-flow so noise does not appear as flow. For level in a closed vessel, the device measures the hydrostatic difference between the bottom tapping and the reference leg. The linearisation function converts height into volume or mass.

PMD55B mounting orientations and side flange options

Process connections are 1/4-18 NPT with IEC 61518 UNF 7/16-20 mounting, DIN 19213 M10 or M12 mounting, Rc 1/4 installation, or coplanar-compatible and coplanar IEC arrangements. The flange raised face has the same material as the membrane. Choose PTFE seals for aggressive media and FKM or EPDM for general service.

Where the PMD55B fits in the Deltabar family

Within the current Endress+Hauser Deltabar line the PMD50 is the lower-cost HART-only transmitter with accuracy up to ±0.05 % when specified as Platinum, and the PMD63B is the diaphragm seal version with capillaries or a temperature isolator for hot or sticky media. The PMD55B sits between them: it adds PROFINET with Ethernet-APL, Bluetooth, Heartbeat Technology and a wider choice of membrane materials and seals. For a single-ended pressure measurement the equivalent models are the Cerabar PMP55 and PMP63B.

PMD55B selection and ordering checklist

• Range: pick the cell that covers the maximum differential pressure and keep the turn down within the accuracy specification.
• Static pressure: choose PN 160 or PN 250 and check negative-side limits, because the 40 bar cell tolerates only 100 bar on the low side.
• Wetted materials: 316L or Alloy C276 membrane, optional gold coating, and the seal material.
• Output and communication: HART or PROFINET over Ethernet-APL, with or without Bluetooth.
• Process connection and orientation: codes A, D, G, K or N, thread type, vent and drain arrangement.
• Housing and approvals: single or dual-compartment housing and the required Ex protection (ATEX, UKCA, CSA, NEPSI, INMETRO, KC, EAC, JPN).
• Software: Heartbeat Technology and Bluetooth if proof testing and remote setting are wanted.

PMD55B installation, commissioning and maintenance

For gas flow, mount the transmitter above the tapping points so condensate runs back into the pipe. For steam, mount below the tapping points and use condensate pots at the same height as the taps. Use a three-valve or five-valve manifold so the device can be isolated and zeroed in service. With a manifold, keep in mind the 110 °C process limit and, above 85 °C, the reduced allowed ambient temperature.

Perform a zero trim with both sides at the same pressure, then verify the range with a calibrator. The warm-up time is five seconds or less. Heartbeat Verification gives a documented pass or fail check without removing the device from the loop, which cuts shutdown work on safety-related loops. Replace the process seals when the device is opened, and note the minimum static pressure of 25 mbar abs at reference conditions with silicone oil.

Typical PMD55B applications in Oman and the GCC

In Oman and the GCC the PMD55B is applied on orifice-plate flow measurement in oil and gas gathering, fuel gas and flare lines, differential pressure across strainers, filters and coalescers, level in pressurised separators and boiler drums, and pump and compressor protection in power and desalination plants. The Super Duplex coplanar option is relevant to seawater cooling and injection lines. In hot desert installations use sunshades and keep impulse lines insulated, and in coastal plants specify corrosion protection for the housing.

Information to send with a PMD55B RFQ

• Part number PMD55B and the full order code from the nameplate if you are replacing a unit.
• Differential pressure range, static pressure and temperature, and the medium (gas, steam or liquid).
• Measurement task: flow with orifice or pitot, level, or filter monitoring.
• Wetted materials, seal material and process connection orientation.
• Output (HART or PROFINET), Ex approval, housing, manifold needs and quantity.

Documents and quotation

The Endress+Hauser Technical Information for the Deltabar PMD55B is attached on this page, with ranges, performance data and the ordering structure.

Send us the PMD55B details above and Seven Star LLC will prepare a quotation for Oman and the GCC.