Endress+Hauser PMC21 Cerabar Ceramic Pressure Transducer

Endress+Hauser PMC21 Cerabar ceramic gauge and absolute transducer

The Endress+Hauser PMC21 is the higher-specification ceramic model of the Cerabar transducer range. It keeps the oil-free capacitive ceramic cell of the PMC11 but adds absolute-pressure cells, a smaller 100 mbar range, 0.3 % reference accuracy, cable and IO-Link connection choices, and optional hazardous-area, marine and oxygen-cleaning versions. Seven Star LLC supplies the PMC21 in Oman and the GCC as an independent supplier in Muscat.

Reading the model against the ordering table: the “Sensor range” code gives the cell and the principle together, so 1H is a 1 bar gauge cell and 2H a 1 bar absolute cell; the “Electrical connection” code gives the cable length (A, B, C for 5, 10, 25 m), the M12 plug (M) or the valve plugs (U, V); and the “Service” code carries oil-and-grease cleaning (HA), oxygen cleaning (HB) and the minimum alarm current setting.

PMC21 technical specifications

How the PMC21 sensor and signal path work

The ceramic diaphragm deflects under pressure and a capacitance change between ceramic electrodes is converted by the electronics into a loop current. For gauge cells a vent path to atmosphere is the reference; for absolute cells the reference is a sealed vacuum, which makes the PMC21 suitable for barometric-independent readings. The ceramic is described in the datasheet as guaranteed against overload of up to 40 times nominal pressure and as usable in absolute vacuum.

Alarm behaviour follows NAMUR NE 43: the usable range is 3.8 to 20.5 mA and the factory failure level is above 21 mA, with a minimum-alarm option for systems that expect a low failure signal. The loop tolerates a ripple of ±5 % on the supply while staying within the reference accuracy.

Where the PMC21 fits and related Cerabar models

Choose the PMC21 over the PMC11 when you need absolute pressure, a lower range, cable-ready wiring or any approval. Choose the PMP21 when the range exceeds 40 bar or the medium is unsuitable for ceramic; the PMP21 reaches 400 bar and a process temperature range of –40 to +100 °C. The PMC11 and PMP11 are the gauge-only, 0.5 % models without approvals. For hygienic duty the PMP23 is the matching metal-diaphragm model.

The device also offers a plug-on PHX20 display on valve-plug versions, which is convenient for local verification on skids without a loop indicator.

Selecting the PMC21: ordering checklist

• Decide gauge or absolute first, because it changes the cell code and the vacuum behaviour.
• For ranges below 1 bar, check the vacuum resistance: 0.7 bar abs on the 100 mbar gauge cell, 0.5 bar abs on 250 mbar, zero on the others.
• Select the connector: cable lengths of 5, 10 or 25 m, M12 plug with optional IO-Link, or valve plug.
• State the approvals needed (hazardous area, DNV GL, ABS or RINA) so the correct version is configured.
• Ask for oxygen cleaning if the medium is oxygen, and respect the maximum pressure and temperature given for oxygen service.
• Choose whether a minimum alarm current is required by your control system.
• Request a 3.1 material certificate or a calibration certificate when the project requires one.

PMC21 installation, commissioning and care

Apply the same tapping-point rules as for any Cerabar: shut-off valve above the tap on gas lines, siphon on steam, and mounting at tapping height on liquids. For oxygen systems, exclude oils and plastics, keep to the datasheet pmax and Tmax values and install only the version ordered with oxygen cleaning.

Orientation influences zero on small ranges, by up to 0.3 mbar below 1 bar. On the 100 and 250 mbar cells a temperature step can add a further 0.3 mbar, so keep the sensor out of direct sun and away from heat sources. During commissioning record the loop current at zero and at span, and keep that record for later comparison. Cables should leave the device in a downward loop to prevent moisture ingress to the vent element; M12 connectors need their seal and cap seated fully. In service, the unit is maintenance-free apart from periodic verification.

Typical PMC21 applications in Oman and the GCC

The absolute option suits vacuum and low-pressure service such as condenser and deaerator monitoring on power and desalination units, vacuum degassing and packaging. The marine approval versions fit offshore support vessels and platform utilities where class approval is required. The IP66/68 cable versions are practical on wash-down areas and wet pits, while the 100 mbar range serves furnace draft, filter and ventilation monitoring in HVAC and process buildings. In dusty desert installations the sealed ceramic cell and 316L body resist abrasive dust and the high humidity of coastal sites.

PMC21 ordering codes summary

Information to send with an RFQ for the PMC21

• Gauge or absolute, and the required range and unit.
• Connector type and cable length, and whether IO-Link is needed.
• Process thread (ISO 228, DIN 13, ASME or JIS) and seal.
• Approvals required and the area classification.
• Medium and temperature; flag oxygen service explicitly.
• Quantity and delivery location.

Documents and quotation

The manufacturer technical information that covers the PMC21 is attached to this page. Please read the approvals and oxygen sections against your project requirements.

Send the part number with your range and connection details and we will confirm the version and prepare a quotation for delivery in Oman and the GCC.