Endress+Hauser PMD50 Deltabar HART DP Transmitter

Endress+Hauser PMD50 Deltabar HART differential pressure transmitter

The Endress+Hauser PMD50 is a HART differential pressure transmitter with a metallic process membrane for monitoring differential pressure, level and flow in liquids and gases. It is the straightforward, standard-industry member of the Deltabar family: one communication protocol (4 to 20 mA with HART 7), a colour display with a magnetic button, wizard-guided commissioning and write protection that can be set by hardware or software. Seven Star LLC supplies the PMD50 in Oman and the GCC as an independent supplier based in Muscat.

Measuring cells run from 100 mbar to 40 bar (1.5 to 600 psi) with static pressure up to 250 bar (3 626 psi), and the Platinum version reaches ±0.05 % reference accuracy. The datasheet quotes a response time below 100 ms in its summary, with the detailed dynamic data given per cell in the performance section.

PMD50 technical specifications

Values are from the Endress+Hauser Technical Information for the Deltabar PMD50 (HART). Pressure limits depend on the ordered process connection and seal.

How the PMD50 works

Each process pressure deflects its own metallic membrane. A fill fluid, silicone oil or inert oil, passes the pressures to the two sides of a silicon measuring element with a middle diaphragm. The net deflection follows the difference between p1 and p2, and a semiconductor resistance bridge converts it into an electrical signal that the electronics scale, linearise and output as 4 to 20 mA with HART. The primary variable is pressure, the secondary variable is sensor temperature and the tertiary variable is electronics temperature.

The linearisation function converts measured pressure into height or volume using user tables of up to 32 point pairs. In flow applications the low flow cut-off parameter suppresses small flows that would otherwise produce a noisy measured value; it is preset to 5 % when the square root output transfer function is used.

PMD50 compared with the other Deltabar models

The PMD50 shares its measuring cell technology with the established Deltabar line, so existing knowledge of orientation codes, manifolds and impulse piping carries over. If you only need a gauge pressure measurement, the single-sided counterpart in the Cerabar range is the PMP63B or the diaphragm seal PMP55.

PMD50 selection and ordering checklist

• Differential range: choose the cell whose upper limit covers the maximum expected differential pressure; do not oversize, because turn down above 5:1 reduces the Platinum accuracy.
• Static pressure class: PN 160 or PN 250, noting the negative-side limit for the 40 bar cell.
• Membrane and seals: 316L or Alloy C276 membrane with PTFE, FKM, EPDM or FFKM seals matching the medium.
• Fill fluid: silicone oil as the general choice, or inert oil, which must not be used below –20 °C.
• Process connection: 1/4-18 NPT side flanges with the mounting thread you need (UNF 7/16-20, M10 or M12) and cast 316L or other flange material.
• Housing and approvals: aluminium or stainless dual-compartment housing, and the Ex protection type required.
• Marine: the datasheet lists ABS marine approval for the family; check the code if class approval matters.

PMD50 installation, commissioning and maintenance

Mount the transmitter to suit the medium: above the tapping points for gas so condensate drains away, below them for steam with condensate pots, and below the lowest tapping for liquid. Use a manifold so zeroing is possible while the process stays online. Where process temperature exceeds 85 °C, apply the reduced ambient temperature rule and insulate impulse lines sensibly.

Commissioning is wizard-driven: set the units, range and damping, then trim zero with equal pressure on both sides. The magnetic button on the housing lets you operate the colour display through the closed cover, which is handy in Ex d enclosures. For maintenance, keep a record of the zero drift: the datasheet gives ±0.05 % of URL in the first year on most cells. Use maximum, not nominal, response values when the transmitter acts in a control or safety circuit.

Typical PMD50 applications in Oman and the GCC

The PMD50 is used across Oman and the GCC for differential pressure on strainers, coalescers and cartridge filters, orifice-plate flow on cooling water, fuel gas, air and steam headers, and level in closed tanks in power, water and process plants. In desalination units it monitors membrane and cartridge filter pressure drop, and in oil and gas facilities it supports pump and compressor protection. In very hot sites avoid direct sun on the housing, route impulse lines away from hot surfaces, and use the stainless housing in coastal environments with salt-laden air.

Information to send with a PMD50 RFQ

• Part number PMD50 and the complete order code if you are replacing an installed unit.
• Differential pressure range, static pressure and process temperature.
• Medium (gas, steam or liquid) and measurement task: flow, level or filter monitoring.
• Wetted material, seal material, fill fluid and process connection.
• Ex approval, housing material, manifold requirement and quantity.

Documents and quotation

The Endress+Hauser Technical Information for the Deltabar PMD50 is attached on this page, with the ranges, performance tables and ordering structure.

Send us the PMD50 details above and Seven Star LLC will prepare a quotation for Oman and the GCC.