Waterpilot FMX21

Summary

Product identification

The Waterpilot FMX21 is a compact pressure transmitter designed for hydrostatic level measurement. It is available in three main housing versions:

• Stainless steel housing, 22 mm (0.87 in) external diameter: Suitable for drinking water, boreholes, and narrow wells.
• Stainless steel housing, 42 mm (1.65 in) external diameter: Heavy-duty version with a flush-mounted process isolating diaphragm, ideal for wastewater applications.
• Plastic insulation, 29 mm (1.14 in) external diameter: Robust version for saltwater applications, such as on ships.

Operating limits

General

• Overload resistance: High resistance to overload.
• Over Pressure Limit (OPL): Depends on the lowest-rated component, including the process connection. Must be considered with pressure-temperature dependency and is for limited periods.
• Maximum Working Pressure (MWP): Depends on the lowest-rated component, including the process connection. Can be applied indefinitely and is indicated on the nameplate.

Process

• Medium temperature range:
  • Stainless steel housing versions: –10 to +70 °C (+14 to +158 °F)
  • Plastic insulated version: 0 to +50 °C (+32 to +122 °F)
• Medium temperature limit: Not explicitly stated, but related to the medium temperature range.

Environment

• Ambient temperature range: –10 to +70 °C (+14 to +158 °F)
• Storage temperature range: Not specified.
• Degree of protection: Not specified.
• Electromagnetic compatibility (EMC): Not specified.

Feed water

• Drinking water suitability: KTW, NSF, ACS approvals.

Product water

• Approvals:
  • KTW, NSF, ACS (for drinking water)
  • ATEX, FM, CSA
  • Marine approvals: GL, ABS, BV, DNV

Electrical

Input

• Measured variable: Hydrostatic pressure (liquid).
• Optional Pt100: Temperature measurement.
• Measuring range:
  • Gauge pressure: 0 to 0.1 bar (0 to 1.5 psi) up to 0 to 20 bar (0 to 300 psi).
  • Absolute pressure: 0 to 2 bar (0 to 30 psi) up to 0 to 20 bar (0 to 300 psi).
  • Customer-specific measuring ranges are available.
• Output units: Configurable to %, mbar, bar, kPa, MPa, mmH₂O, mH₂O, inH₂O, ftH₂O, psi, and other level units.
• Input signal: Change in capacitance.
• Optional Pt100: Change in resistance.

Output

• Output signal:
  • 4 to 20 mA Analog (2-wire) for hydrostatic pressure.
  • 4 to 20 mA HART (2-wire) with HART 6.0 digital communication for hydrostatic pressure.
• Signal range: 3.8 to 20.5 mA.
• Options: Max. alarm (21 to 23 mA), Hold measured value, Min. alarm (3.6 mA).
• Damping: Continuously adjustable from 0 to 999 s via HART; factory setting is 2 s.

Power supply

• Supply voltage:
  • Non-hazardous area: 10.5 to 35 VDC.
  • Hazardous area: 10.5 to 30 VDC.
• Power consumption:
  • ≤ 0.805 W at 35 VDC (non-hazardous area).
  • ≤ 0.690 W at 30 VDC (hazardous area).
• Current consumption:
  • Max: ≤ 23 mA.
  • Min: ≥ 3.6 mA.

Communication protocol

• 4 to 20 mA analog.
• 4 to 20 mA HART (HART 6.0).
• Manufacturer ID: 17 (11 hex).
• Device type ID: 25 (19 hex).
• HART specification: 6.
• HART load: min. 250 Ω.
• Supported functions: Burst mode, Additional transmitter status, Device locking, Alternative measuring modes, Catch variable, Long tag.

Mechanical / hydraulic

Dimensions

• External diameter:
  • 22 mm (0.87 in)
  • 42 mm (1.65 in)
  • Max. 29 mm (1.14 in)
• Probe cable: Overall external diameter: 8 mm (0.31 in) ±0.25 mm (0.01 in).
• Pressure compensation tube: External diameter of 2.5 mm (0.1 in), internal diameter of 1.5 mm (0.06 in).
• Dimensions of other components (suspension clamp, cable mounting screw, terminal box, head transmitters) are detailed in the document.

Materials

• Housing: Stainless steel or plastic insulation.
• Seals: FKM Viton or EPDM.
• Process isolating diaphragm: Ceramic.
• Materials for specific components are detailed in the document.

Weight

• Additional weight is available as an accessory for certain versions.
• Specific weight values are detailed in the document.

Mounting

• Installation: Can be mounted using a suspension clamp or a cable mounting screw with thread.
• Guide tube: Recommended for stability if sideways movement is a concern; internal diameter should be at least 1 mm (0.04 in) larger than the probe's external diameter.
• Terminal box: Recommended for dry environments or outdoor installation; provides humidity and climatic protection.
• Cable length tolerance: < 5 m (16 ft): ±17.5 mm (0.69 in); > 5 m (16 ft): ±0.2 %.
• Max. cable length (freely suspended, Ex approval): 300 m (984 ft).

Performance characteristics

• Reference accuracy:
  • Standard: ±0.2 % of set span.
  • PLATINUM version (optional): ±0.1 % of set span.
• Resolution: 1 μA (current output).
• Long-term stability:
  • ≤ 0.1 % of URL/year.
  • ≤ 0.25 % of URL/5 years.
• Influence of medium temperature: Affects zero output and span; specified as a percentage of set span with dependency on TD.
• Warm-up time:
  • Device: < 6 s.
  • Pt100: 300 s.
• Response time:
  • Device: 400 ms (T90), 500 ms (T99).
  • Pt100: 160 s (T90), 300 s (T99).

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