Monitoring Liquids and Energy with Ultrasonic Flowmeters

The internal liquid does not come into contact with the FDT-40 series clamp-on ultrasonic flow meter. Compared to other available devices, this technology has several fundamental advantages, such as: lack of moving parts to replace and maintain, lack of pressure head loss, inexpensive installation, lack of fluid compatibility requirements, and an extensive, bi-directional measuring area which guarantees dependable readings at both extremes of flow rate.

There are several configurations of FDT-40 series which allow customization of features to meet the requirements of the specific application.



  • Liquid Types: Most clean liquids or liquids containing small amounts of suspended solids or gas bubbles
  • Velocity Range: Bi-directional to greater than 40 FPS (12 MPS)
  • Flow Accuracy:
    •    Larger Than 50 mm (2"): ±1% of reading or ±0.01 FPS (0.003 MPS), whichever is greater
    •    25 to 50 mm (1 to 2"): ±1% of reading or ±0.04 FPS (0.012 MPS), whichever is greater
  • ¾" (19 mm) and Smaller: ±1% of full scale
  • Sensitivity Flow: 0.001 FPS (0.0003 MPS)
  • Repeatability: 0.5% of reading


  • Power Requirements (AC): 95 to 264 Vac 47 to 63 Hz @ 17 VA maximum standard, 20 to 28 Vac 47 to 63 Hz @ 0.35 A maximum (“-24 VAC” models), 10 to 28 Vdc @ 5 W maximum (“-VDC” models)
  • Protection: Auto resettable fuse, reverse polarity and transient suppression
  • Display: Two line LCD, LED backlit; top row 18 mm (0.7") height, 7-segment; bottom row 9 mm (0.35") height, 14-segment
  • Flow Rate Indication: 8-digit positive, 7-digit negative maximum; auto decimal, lead zero blanking
  • Flow Totalizer: 8-digit positive, 7-digit negative maximum (re-set via keypad press, software, network command or momentary contact closure
  • Enclosure NEMA 4 (IP65) Construction: Powder-coated aluminum, polycarbonate, stainless steel, polyurethane, nickel-plated steel mounting brackets
  • Size (Electronic Enclosure Only): 152 W x 112 H x 56 mm D (6.0 x 4.4 x 2.2")
  • Conduit Holes: (2) ½ NPT female (1) ¾ NPT female
  • Temperature: -40 to 85 °C
  • Configuration: Via optional keypad or PC running software (Note: not all configuration parameters are available from the keypad – i.e. flow and temperature calibration and advanced filter settings)
  • Engineering Units Flow Meter: Feet, gallons, cubic feet, million gallons, barrels (liquid and oil), acre-feet, lbs, meters, cubic meters, liters, million liters, kg
  • Inputs/Outputs USB 2.0: For connection of a PC running configuration utility
    •     RS485: MODBUS RTU command set
    •     4 to 20 mA: 12-bit, internal power, can span negative to positive flow/ energy rates
    •     0 to 1000 Hz: Open-collector, 12-bit, can span negative to positive rates; square-wave or turbine meter simulation outputs
  • Two Alarm Outputs: Open-collector, configure as rate alarm, signal strength alarm or totalizer pulse



  •     Standard (FDT-41 thru 46): NEMA 6 (IP67), PVC, PEI, Nylon cord grip, PVC cable jacket
  •     Temperature: -40 to 60 °C (-40 to 140 °F)
  •     FDT-41 thru 46 with “-HT” option, FDT-47 and FDT-48: NEMA 6 (IP67), CPVC, PEI, Nylon cord grip, PVC cable jacket
  •     Temperature: -40 to 90 °C (-40 to 194 °F)
  •     FDT-47 “-HT”: NEMA 6 (IP67), PTFE, polyimide, Nickel-plated brass cord grip, PFA cable jacket
  •     Temperature: -40 to 176 °C (-40 to 350 °F)
  • Frequency:
    •     FDT41 thru 46: 2 MHz
    •     FDT-47: 1 MHz
    •     FDT-48: 500 KHz
  • Cables: RG59 coaxial, 75 Ω or twin axial, 78 Ω (optional armored conduit)
  • Cable Length: Standard 6 m (20') 300 m (990') maximum in 3 m (10') increments; submersible conduit limited to 30 m (100')

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