Waterpilot FMX11

Summary

Product identification

Product: Waterpilot FMX11 Type: Hydrostatic level measurement transmitter Document: TI01524P/00/EN/01.20 Date: 2020-08-03

Application

The Waterpilot FMX11 is a pressure sensor for hydrostatic level measurement in fresh water applications. Typical uses include:

• Level measurement in groundwater wells (suitable for 1" pipes)
• Surface water monitoring in rivers and lakes
• Level monitoring in drinking water extraction (e.g., in water towers)

Measuring principle

The device uses a semiconductor-based Wheatstone bridge. Process pressure deflects a diaphragm, which transfers pressure via filling oil to the bridge. The resulting change in output voltage is measured and evaluated.

Input

• Measured variable: Hydrostatic pressure of a liquid.
• Measuring range: Customer-specific measuring ranges or factory presets.
  • Examples include: 0.2 to 1.0 bar (absolute) corresponding to 2 to 10 mH₂O.
• Input signal: Change in capacitance.

Output

• Output signal: 4 to 20 mA analog, 2-wire.
• Signal range: 2 to 22 mA.
• Maximum load: Depends on supply voltage (U), calculated as: RLmax ≤ (U - 8 V) / 22 mA. Additional resistances must be subtracted.

Power supply

• Supply voltage: 8 to 28 VDC.
• Power consumption: ≤ 0.62 W at 28 VDC.
• Current consumption: Max. ≤ 22 mA, Min. ≥ 2 mA.
• Electrical connection: Reverse polarity protection is integrated.

Performance characteristics

• Reference operating conditions: As per IEC 60770, with stable ambient temperature, humidity, and pressure.
• Reference accuracy:
  • Sensor measuring range ≥ 400 mbar: ≤ ±0.35 %
  • Sensor measuring range < 400 mbar: ≤ ±0.50 %
• Long-term stability: ≤ ±0.1 % of URL/year at reference conditions.
• Influence of medium temperature:
  • -10 to +70 °C: < (0.4 + 0.4 x TD)% of set span.
  • Temperature coefficient: 0.15 %/10 K of URL (0 to +70 °C).
• Warm-up period: ≤ 10 s.
• Response time: T90 ≤ 15 ms, T99 ≤ 45 ms.

Installation

• Cable length: Can be limited for freely suspended devices (max. 300 m).
• Install in areas free from flow and turbulence, or use a guiding tube.
• A protection cap is provided to avoid mechanical damage to the measuring cell.
• Cable should terminate in a dry room or suitable terminal box.

Environment

• Ambient temperature range:
  • FMX11: –10 to +70 °C
  • Terminal box (optional): –40 to +80 °C
• Storage temperature range:
  • FMX11: –10 to +70 °C
  • Terminal box (optional): –40 to +80 °C
• Degree of protection:
  • FMX11: IP68 (permanently hermetically sealed at 10 bar)
  • Terminal box (optional): IP66, IP67
• Electromagnetic compatibility (EMC): In accordance with EN 61326 series. Maximum deviation: < 0.5 % of span.

Process

• Medium temperature range: 0 to +70 °C.
• Medium temperature limit: –10 to +70 °C (accuracy specifications may be exceeded outside the range).
• Process pressure range: Operation must remain within specified limits.

Mechanical construction

• Dimensions: See diagrams in the document.
  • Level probe: ø22 mm diameter.
  • Suspension clamp: Approx. 52 mm width.
  • Terminal box: Approx. 120 x 80 mm footprint.
• Weight:
  • Level probe: 165 g
  • Extension cable: 32 g/m
  • Suspension clamp: 170 g
  • Terminal box: 235 g
• Materials:
  • Materials in contact with process: 316L, EPDM seal, POM protection cap.
  • Extension cable insulation: TPE.
  • Suspension clamp: 316L and fiber-glass reinforced PA.
  • Terminal box housing: PC.

Certificates and approvals

• CE mark
• CULUS listing
• Drinking water approval: KTW, NSF61, ACS, DVGW
• Pressure Equipment Directive 2014/68/EU (PED)

Ordering information

Detailed ordering information is available via the Endress+Hauser website Product Configurator or sales centers.

• Scope of delivery: Measuring device, certificates, optional accessories.

Accessories

• Suspension clamp (Order number: 52006151)
• Terminal box (Order number: 52006152)

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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