Deltabar S FMD71 electronic dp

Summary

Product Identification

• Product Name: Deltabar FMD71, FMD72
• Product Type: Electronic differential pressure transmitter with ceramic and metallic measuring cells.
• Communication Protocol: HART 6.0 (2-wire)

Field of Application

This device is designed for measuring the level, volume, or mass of liquids in pressurized and vacuum vessels.

Key Benefits

• Increased Process Availability: Electronic differential pressure system eliminates traditional mechanical issues.
• Minimized Safety Risks: Enhanced architecture and design of the electronic differential pressure system.
• Lower Total Cost of Ownership: Reduced installation time, maintenance, downtime, and spare parts requirements.
• Multivariable Measurement: HART-based measurement of differential pressure, head pressure, and sensor temperatures from a single system.
• Continuous Health Indication: System health monitoring via HART-based diagnostics.
• High Reproducibility and Long-Term Stability.
• Overload-Resistant and Function-Monitored.

Measuring Principle

Ceramic Process Membrane (Ceraphire®)

• Oil-free ceramic measuring cell where pressure acts directly on the membrane.
• Pressure-dependent capacitance change is measured.
• Advantages:
  • Guaranteed overload resistance up to 40 times the nominal pressure.
  • Made from ultrapure 99.9% ceramic.
  • Extremely high chemical durability.
  • Less relaxation and high mechanical durability.
  • Usable in absolute vacuum up to 150 °C (302 °F).
  • Suitable for small measuring ranges.

Metallic Process Membrane

• Process pressure deflects the metallic membrane, transferring pressure via a fill fluid to a Wheatstone bridge.
• Advantages:
  • Suitable for process pressures up to 40 bar (600 psi).
  • Fully welded process membrane.
  • Small, flush-mounted process connections.
  • Significantly reduced thermal effect compared to diaphragm seal systems with capillaries.

Measuring System

The system comprises two sensor modules (High Pressure - HP, Low Pressure - LP) and one transmitter. The transmitter calculates the differential pressure (level) using the digital values from both sensors. The HP sensor is mounted on the lower measuring connection, and the LP sensor is mounted above the maximum level.

Input

• Measured Process Variables:
  • Pressure HP
  • Pressure LP
  • Sensor temperature HP
  • Sensor temperature LP
  • Transmitter temperature
• Calculated Process Variables:
  • Differential pressure
  • Level (level, volume, or mass)

FMD71: Measuring Range of Individual Sensors

See the official PDF for exact tabulated values for Gauge and Absolute pressure ranges, MWP, OPL, and Vacuum resistance.

FMD72: Measuring Range of Individual Sensors

See the official PDF for exact tabulated values for Gauge and Absolute pressure ranges, MWP, OPL, and Vacuum resistance.

Output

• Output Signal: 4 to 20 mA with superimposed digital communication protocol HART 6.0, 2-wire.
• Signal Range: 3.8 to 20.5 mA
• Signal on Alarm:
  • Max. alarm (factory setting 22 mA): configurable from 21 to 23 mA.
  • Hold measured value: last measured value is held.
  • Min. alarm: 3.6 mA (as per NAMUR NE43).

Dynamic Behavior

Current Output

• Dead time (t₁): Max. 120 ms
• Time constant (T₆₃, t₂): Max. 120 ms
• Time constant (T₉₀, t₃): Max. 280 ms

HART

• Dead time (t₁): Max. 1100 ms
• Response time (acyclic): Min. 330 ms, typically 590 ms
• Response time (cyclic/burst): Min. 160 ms, typically 350 ms
• Cycle time (update time) for cyclic (burst): Min. 300 ms

Damping

• Infinitely variable from 0 to 999 seconds.
• Can be set via local display, handheld terminal, or PC.
• Can also be controlled via DIP switch on the electronic insert.
• Factory setting: 2 s.

Energy Supply

• Supply Voltage:
  • 4 to 20 mA HART (non-hazardous area): 13 to 45 VDC
  • 4 to 20 mA HART (hazardous area): 12 to 45 VDC
• Maximum Load Resistance: Dependent on supply voltage; refer to load diagrams in the official PDF.
• Residual Ripple: No influence on 4 to 20 mA signal up to 5% residual ripple.
• Influence of Power Supply: ≤ 0.0006 % of the URV/1 V.
• Overvoltage Protection: Available as an option; nominal functioning DC voltage 600 V, nominal discharge current 10 kA.

Performance Characteristics (Ceramic Process Membrane)

Reference Operating Conditions

• As per IEC 62828.
• Ambient temperature: constant, +21 to +33 °C (+70 to +91 °F).
• Humidity: constant, 5 to 80 % rH.
• Atmospheric pressure: constant, 860 to 1060 mbar.
• Measuring cell position: constant, horizontal ±1°.

Influence of Installation Position

• Calibration position (axis horizontal): No measurement error.
• Process membrane upwards: < +0.2 mbar (+0.003 psi).
• Process membrane downwards: < –0.2 mbar (–0.003 psi).
• This effect can be corrected via position adjustment.

Resolution

• Current output: 1 μA.
• Display: Configurable.

Vibration Effects (IEC 61298-3)

• Up to 10 to 60 Hz: ±0.35 mm.
• 60 to 500 Hz: 2 g.

Application Limits

A ratio of level to head pressure or differential pressure to static pressure of 1:10 is recommended.

Reference Accuracy

See the official PDF for exact tabulated values for Reference Accuracy (A) and Calculated Reference Accuracy (ADiff) for various sensor ranges and types (Standard, Platinum).

Thermal Change

See the official PDF for exact tabulated values for Thermal Change (Ttotal, Tspan, Tzero point) for various sensor ranges and types (Standard, High-temperature, Hygienic).

Total Performance

See the official PDF for exact tabulated values for Total Performance (TP) for various sensor ranges.

Long-Term Stability

See the official PDF for exact tabulated values for Long-Term Stability (L) for various measuring ranges and durations (1 year, 10 years).

Total Error

See the official PDF for exact tabulated values for Total Error (TE) for various measuring ranges and types.

Performance Characteristics (Metallic Process Membrane)

Reference Operating Conditions

• As per IEC 62828.
• Ambient temperature: constant, +21 to +33 °C (+70 to +91 °F).
• Humidity: constant, 5 to 80 % rH.
• Atmospheric pressure: constant, 860 to 1060 mbar.
• Measuring cell position: constant, horizontal ±1°.

Influence of Installation Position

• Sensor with 1/2" thread and silicone oil:
  • Upwards: < +4 mbar (+0.06 psi).
  • Downwards: < –4 mbar (–0.06 psi).
• Sensor with thread > 1/2" and flanges:
  • Upwards: < +10 mbar (+0.145 psi).
  • Downwards: < –10 mbar (–0.145 psi).
• This effect can be corrected via position adjustment.

Resolution

• Current output: 1 μA.
• Display: Configurable.

Vibration Effects (IEC 61298-3)

• Up to 10 to 60 Hz: ±0.35 mm.
• 60 to 500 Hz: 2 g.

Application Limits

A ratio of level to head pressure or differential pressure to static pressure of 1:10 is recommended.

Reference Accuracy

See the official PDF for exact tabulated values for Reference Accuracy (A) and Calculated Reference Accuracy (ADiff) for various sensor ranges and types (Standard, Platinum).

Thermal Change

See the official PDF for exact tabulated values for Thermal Change (Ttotal, Tspan, Tzero point) for various sensor ranges.

Total Performance

See the official PDF for exact tabulated values for Total Performance (TP) for various sensor ranges.

Long-Term Stability

See the official PDF for exact tabulated values for Long-Term Stability (L) for various measuring ranges and durations (1 year, 5 years, 10 years).

Total Error

See the official PDF for exact tabulated values for Total Error (TE) for various measuring ranges.

Mounting

• Prevent moisture ingress into the housing during installation and operation.
• Consider using separators and drain valves for media containing solids.
• Point cables and connectors downwards where possible.
• Mounting Location: Suited for vessels with pressure overlay, vacuum vessels, high distillation columns, and areas with changing ambient temperatures.
• Orientation:
  • Transmitter: Any orientation.
  • Sensor modules: Orientation can cause a zero point shift, correctable at the device.
• General Installation: Housings are rotatable for optimal alignment.

Thermal Insulation (FMD71 High-Temperature Version)

Insulation height is limited and indicated on the device. Applicable for insulation material with heat conductivity ≤ 0.04 W/(m x K).

• Maximum ambient temperature (TA): 70 °C (158 °F).
• Maximum process temperature (TP): 150 °C (302 °F).

Installing Sensor Modules

• Always install HP sensor module below the lowest measuring point and LP sensor module above the highest measuring point.
• Avoid mounting in the filling curtain, areas affected by agitator pressure pulses, or pump suction areas.
• Mounting bracket available as an option or accessory.

Installing the Transmitter

The transmitter is installed using the supplied mounting bracket, which can be fitted to pipes (1¼" to 2") or walls.

Environment

Ambient Temperature Range

• Standard version: -40 to +80 °C (-40 to +176 °F)
• High-temperature version: See official PDF for specific limits related to insulation.

Storage Temperature

• See official PDF for specific range.

Climate Class

• See official PDF for classification.

Degree of Protection

• Standard: IP67
• Ex ia / Ex ic: IP66/IP67
• Ex tD / Ex nA / FM / CSA: IP66/IP67

Vibration Resistance

• As per IEC 61298-3.

Electromagnetic Compatibility (EMC)

• Meets requirements of EN 61000-4-5 (1kV test voltage).

Process

Process Temperature Range

• FMD71 (Ceramic Membrane):
  • Standard: -40 to +150 °C (-40 to +302 °F)
  • High-temperature version: See official PDF for details related to insulation.
• FMD72 (Metallic Membrane): See official PDF for specific temperature ranges.

Process Pressure Range

• See official PDF for exact tabulated values for FMD71 and FMD72.

Mechanical Construction

• Device Height: See official PDF for dimensions related to T14 and T17 transmitter housings and sensor housings.
• Process Connections: Various internal and flush membrane options available for FMD71 and FMD72. Refer to official PDF for detailed diagrams and specifications.
• Materials in Contact with Process: See official PDF for material options (e.g., Stainless Steel, Hastelloy, Tantalum, PVDF).
• Materials Not in Contact with Process: See official PDF for material options.

Certificates and Approvals

• CE approval
• RoHS
• RCM marking
• Ex approvals (refer to specific documentation)
• Suitable for hygiene applications
• Pressure Equipment Directive 2014/68/EU (PED)
• CRN approval
• ANSI/ISA 12.27.01 classification
• Inspection certificates available.

Ordering Information

• Refer to the official PDF for detailed ordering codes and options.
• Scope of Delivery: Includes device, mounting bracket, operating instructions, and test reports/declarations as ordered.
• Accessories: Various accessories are available, including documentation, service-specific items, and mounting hardware.

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Disclaimer: This summary is based on extracted text and may not include all figures, footnotes, or revisions. Contractual data must match the specific OEM PDF revision used for the project.

Official datasheet (PDF)

Lenntech datasheet mirror