Endress+Hauser PMP21 Cerabar Metal Pressure Transducer

Endress+Hauser PMP21 Cerabar metal-diaphragm pressure transducer

The Endress+Hauser PMP21 is the metal-diaphragm, high-range member of the Cerabar transducer family. It measures gauge or absolute pressure from 400 mbar to 400 bar with up to 0.3 % reference accuracy, and uses a fully welded 316L sensor for process media where a ceramic face is unsuitable or the pressure is too high. Seven Star LLC supplies the PMP21 in Oman and the GCC as an independent supplier in Muscat.

The code breakdown in the datasheet is short: the “Sensor range” option gives the cell and principle (codes beginning with 1 for gauge cells and with 2 for absolute cells, for example 2U for 100 bar absolute and 2W for 400 bar absolute); the connector option gives a cable (A, B, C), M12 plug (M) or valve plug (U, V); and the process-connection option gives the thread. The PMP21 is the metal counterpart of the ceramic PMC21 and the higher-range sibling of the PMP11.

PMP21 technical specifications

How the PMP21 measures pressure

Process pressure deflects the 316L isolating diaphragm. A fill fluid carries the pressure to a silicon measuring element with a Wheatstone bridge, and the bridge output change is measured and linearised by the electronics. Because the sensor is fully welded, the construction is suited to high process pressure and to slim, flush-mounted connections that avoid a cavity in front of the diaphragm.

Compared with the ceramic PMC21, this principle trades chemical durability against ceramic for much higher pressure capacity and a lower minimum process temperature. The long-term stability figures in the datasheet are given for one, five and eight years and should be used when planning calibration intervals.

Where the PMP21 fits in the Cerabar range

The PMP21 is chosen when the range is above 40 bar, when the process can reach –40 °C, or when a robust metal face is preferred. Typical neighbours in a spare-parts list are the PMP11 (gauge only, 0.5 %), the PMC21 (ceramic, up to 40 bar) and the PMP23 (hygienic, flush, with clamp and dairy fittings). For loops that need HART, a display or high accuracy, step up to the PMP43 or PMP50 transmitters. Weld-in adapters in G ½ 316L (with a 3.1-certified version) and a brass weld-in tool are listed as accessories.

Selecting the PMP21: ordering checklist

• Gauge or absolute, and the cell closest above the maximum working pressure.
• Check the OPL of the process connection, since the connection can be rated lower than the cell.
• Confirm the medium is compatible with 316L and that the fill oil is acceptable for the process.
• Choose the process thread and whether a flush-mounted O-ring version with a weld-in adapter is preferred.
• Select connector and cable length, or M12 plug with IO-Link if the system supports it.
• Add approvals (hazardous area, DNV GL, ABS, RINA), minimum alarm current, 3.1 certificate or calibration certificate where specified.
• Remember the turn down limit of the chosen cell before specifying a narrow span.

PMP21 installation, commissioning and maintenance

Fit the shut-off valve above the tapping point for gases and use a siphon on steam. Point the connector downward to protect the pressure compensation element. For flush-mounted units, weld the adapter first, then install the transducer with the pre-mounted FKM seal, keeping the sealing surface clean and unmarked.

• Verify the supply, load and polarity before energising.
• Record zero and span current at commissioning.
• Do not exceed the OPL during pressure tests of the line; isolate the transducer first.
• Inspect threads, seals and cable gland at turnarounds, and replace damaged seals rather than reusing them.

The overvoltage behaviour is specified: the device operates up to 34 V DC without damage but accuracy is not guaranteed above 30 V.

Typical PMP21 applications in Oman and the GCC

High-pressure duty is where the PMP21 earns its place: hydraulic power units, compressor interstage and discharge lines, high-pressure water injection and wash systems, and air receivers at gas-processing and power sites. Marine-approved versions suit offshore vessels and platform utility skids. The 400 bar cells cover the top of the range, while lower ranges can monitor boiler feedwater and desalination high-pressure pumps. The sealed 316L construction copes with salt-laden air and high humidity along the coast, and the wide ambient range handles skids in the desert interior.

PMP21 absolute and gauge range overview

Information to send with an RFQ for the PMP21

• Order code or nameplate photo of the unit being replaced.
• Gauge or absolute, range, and unit.
• Process thread, flush-mounted or not, and whether a weld-in adapter is needed.
• Connector, cable length and any IO-Link requirement.
• Approvals, certificates and cleaning requirements.
• Medium, temperature, pressure peaks and delivery site.

Documents and quotation

The manufacturer technical information that covers the PMP21 is attached to this page. Use it with your process data to confirm the connection and approval options.

Send the part number and your range and connection requirements and Seven Star LLC will confirm availability and issue a quotation for Oman and the GCC.