Deltabar M PMD55

Summary

Product identification

The Deltabar M PMD55 is a differential pressure transmitter with a metallic measuring cell. It is suitable for various measuring tasks, including:

• Flow measurement (volume or mass flow) in gases, vapours, and liquids in conjunction with primary elements.
• Level, volume, or mass measurement in liquids.
• Differential pressure monitoring (e.g., of filters and pumps).

It offers high reproducibility, long-term stability, and a high reference accuracy of 0.10%, with a PLATINUM version achieving up to 0.075%. The device supports a turn down ratio of up to 100:1 and is part of a uniform platform for differential pressure, hydrostatics, and pressure measurements (Deltabar M – Deltapilot M – Cerabar M). It is certified to IEC 61508 Edition 2.0 and IEC 61511 by TÜV NORD for process pressure monitoring up to SIL 2.

Communication protocols supported include HART, PROFIBUS PA, and FOUNDATION Fieldbus.

Input

Measured variable

• Differential pressure, used to derive flow (volume flow or mass flow) and level (level, volume, or mass).

Measuring range

The measuring cell specifications, including maximum measuring range, smallest calibratable span, MWP, OPL, and minimum operating pressure, vary by option.

See the official PDF for exact tabulated values.

Output

Output signal

• 4 to 20 mA with HART communication protocol (HART 6.0, 2-wire)
• PROFIBUS PA (Profile 3.02)
• FOUNDATION Fieldbus

Signal range 4 to 20 mA

• 4 to 20 mA HART: 3.8 to 20.5 mA

Signal on alarm

Configurable as per NAMUR NE 43. Options include Max. alarm, Hold measured value, Min. alarm, Last Valid Out Value, Fail-safe Value, or Wrong Value depending on the communication protocol.

Damping

Adjustable from 0 to 999 s via local display, handheld terminal, or PC. Can also be set via DIP switch. Factory setting is 2 s.

Performance characteristics

Response time

Response times vary by communication protocol:

• HART: Acyclic: min. 330 ms, typically 590 ms. Cyclic (burst): min. 160 ms, typically 350 ms.
• PROFIBUS PA: Acyclic: approx. 23 ms to 35 ms. Cyclic: approx. 8 ms to 13 ms.
• FOUNDATION Fieldbus: Acyclic: typically 70 ms. Cyclic: max. 20 ms.

Reference operating conditions

As per IEC 62828-2, with specific ambient temperature, humidity, atmospheric pressure, and position tolerances.

Total performance

The total performance is influenced by reference accuracy, ambient temperature effect, and static pressure effect.

Resolution

• Current output: 1 μA
• Display: Adjustable.

Long-term stability

Values for 1, 5, and 10 years are provided for different measuring cell ranges.

See the official PDF for exact tabulated values.

Installation

Installation position

The recommended maximum angle to the diaphragm axis is 10°, resulting in a measuring error of ±0.72 mbar. This error is doubled for devices with inert oil. Position-dependent zero point shift can be corrected.

Vibration effects

Specifications for vibration resistance are provided according to GL VI-7-2 and IEC 61298-3 standards.

Warm-up period

• 4 to 20 mA HART: ≤5 s
• PROFIBUS PA: ≤8 s
• FOUNDATION Fieldbus: ≤20 s (or ≤45 s after a TOTAL reset).

Mounting

• Impulse lines should have a monotonic gradient of at least 10%.
• Outdoor impulse lines require anti-freeze protection.
• Condensate traps are recommended for vapour measurements.
• Mounting brackets for wall and pipe mounting are available (standard and heavy-duty versions).

Environment

Ambient temperature range

Specific ranges are provided.

Storage temperature range

Specific ranges are provided.

Climate class

Specific classification provided.

Degree of protection

IP66/68 NEMA 4X/6P for various cable entry options.

Vibration resistance

Tested according to IEC 61298-3.

Process

Process temperature limits

Specific ranges are provided for the transmitter and seals.

Pressure specifications

See the official PDF for exact tabulated values.

Mechanical construction

Housing

Details on housing material and thread options are provided.

Process connection

Various process connections are available, including NPT and UNF threads.

Dimensions for different impulse line configurations (V1, H1, H2) are detailed.

Power supply

Supply voltage

• HART: 11.5 to 30 V DC (intrinsically safe), 11.5 to 45 V DC (other types of protection).
• PROFIBUS PA: 9 to 32 V DC (non-hazardous areas).
• FOUNDATION Fieldbus: 9 to 32 V DC (non-hazardous areas).

Current consumption

• PROFIBUS PA: 11 mA ±1 mA.
• FOUNDATION Fieldbus: 16 mA ±1 mA.

Electrical connection

Cable entry

Various options include M20 gland, M20 thread, G ½" thread, NPT ½" thread, M12 plug, 7/8" plug, HAN7D plug, and M16 valve connector, with corresponding degrees of protection.

Terminals

Specifications for terminal sizes for supply voltage, internal ground, and external ground are provided.

Connector

Details and pin assignments are provided for valve connectors, Harting Han7D plugs, M12 plugs, and 7/8" plugs.

Cable specification

Recommendations for twisted, shielded twin-core cables are given for HART, PROFIBUS PA, and FOUNDATION Fieldbus.

Start-up current

12 mA or 22 mA (selectable).

Residual ripple

No influence on the 4 to 20 mA signal up to ±5 % residual ripple.

Influence of power supply

≤0.001 % of URL/V.

Overvoltage protection

Optional overvoltage protection can be fitted to the device.

Disclaimer: This extraction may miss figures, footnotes, or revisions; contractual data must match the OEM PDF revision used on the project.

Official datasheet (PDF)

Lenntech datasheet mirror