OCF 4.0 Open Channel Flow Monitor
  • Non-Contacting Ultrasonic Sensor
  • Accurate and Verifiable
  • Built-in 50,000 point Data Logger
  • Windows Software
  • USB and RS232 Outputs
  • 4-20mA/0-5V Output
  • 16-digit Totalizer
  • 3 Programmable Control Relays
  • Password Protected
  • Simple 3-key Calibration

Continuously monitor, display, totalize and data log flow through any flume or weir. The OCF 4.0 includes a non-contacting ultrasonic sensor that mounts just 8" (203.2 mm) above the flowing water. It is accurate (±0.25%) and reliable. There is no obstruction to flow and no fouling. Use the built-in Keypad/menu system to select your flume or weir from the Menu and to choose measurement units (gallons, liters etc.) 

The Greyline OCF 4.0 includes built-in 50,000 point Data Logger and flow reporting system. Retrieve data logs with 'Greyline Logger' software – included free with each OCF-4.0. Connect the USB or RS232 output directly to the serial port on your PC or Laptop, or by dial-up connection through modems. Configure the analog output to 0-5V for reduced power consumption.

Use the isolated 4-20mA to transmit flow to remote chart recorders or displays, and the 3 control relays are programmable for level/flow alarm, and flow proportionate pulse (for samplers, chlorinators or remote totalizers). An Intrinsic Safety Barrier is optional for sensor and cable installation in hazardous rated locations. The separate, watertight electronics/display enclosure is mounted at a convenient location within 500 ft (150 m) of the sensor.

Standard features include:

  • sensor - Model PZ15, PVC 
  • sensor cable - 25 ft / 7.6 m RG62AU coaxial
  • enclosure - watertight NEMA4X (IP66) polycarbonate
  • calibration - to any flume or weir with built-in 3-button programmer, password protected
  • displays - Flow/Level values - large 4-digit LCD Totalizer/Menu/Status - 16-digit alphanumeric
  • temperature compensation - automatic
  • outputs - USB, RS-232C, 0-5V, isolated 4-20mA (1000 ohm)
  • data logger - 50,000 point with multi-session and flow report capability
  • PC software for data log retrieval by USB, RS232 or by dial-up connection with modems
  • 1 PC software utilities disk, USB and RS-232C cables
  • 3 relays - programmable flow alarm, flow proportional, failsafe/echo-loss
  • electrical surge protection - AC, sensor, 4-20mA - power input
  • 100-130VAC 50/60Hz, 6.2 Watts maximum
  • 1 Manual - Installation and Operation


SCOPE: This specification covers an ultrasonic, echo-ranging type open channel flow meter as manufactured by Greyline Instruments, Massena, New York / Long Sault, Ontario. This instrument shall provide for indicating, transmitting, totalizing and data logging of the flow rate through a flume, weir, or other primary measuring device.


  1. Flow Monitor to consist of an non-contacting ultrasonic sensor, connecting cable, and a remote enclosure with indicating, transmitting, controlling and data logging electronics.
  2. Measurement accuracy shall be ±0.25% and shall be automatically temperature compensated.
  3. Sensor cable length shall be as required by installation, not to exceed 500 ft (152 m).
  4. System shall have no moving parts and shall not contact flowing water.


  1. Sensor shall withstand accidental submersion to 20 psi.
  2. Sensor minimum range shall be 8" (203.2 mm) and maximum range shall be 15 ft (4.57 m).
  3. Sensor shall be constructed of PVC.
  4. Sensor operating temperature shall be from -40°F to 150°F (-40°C to 65°C).
  5. Sensor shall include integral temperature sensor. Temperature sensors requiring separate mounting and wire runs shall not be accepted.


  1. Provide RG62AU coaxial cable, minimum length 25 ft (7.6  m), with waterproof, potted bond to the Sensor head.
  2. Level and temperature signals shall be conducted on one single coaxial cable. Separate or multiple-conductor cables shall not be accepted.
  3. Extended sensor cable shall be RG62AU coaxial to a maximum of 500 ft (152m). Cable shall be spliced with screw terminal connections in manufacturers recommended steel NEMA4 Junction Box.
  4. Sensor cable shall be installed in grounded metal conduit.


  1. The transmitter shall provide for field calibration to common primary metering devices, plus allow entry of "K" and "n" values for calibration to nonstandard flumes, weirs or open channels.
  2. Field-calibration shall be via built-in 3-key calibration system with menu selection of parameters. Systems requiring calibration by Parameter codes, BCD switches or external calibrators shall not be accepted.
  3. Calibration data shall be password protected and permanently stored through power interruptions for a minimum of 12 months.
  4. Field calibration shall allow selection and automatic conversion of measurement units, measurement span, high/low flow alarm relay and flow proportional relay pulse rates.
  5. Transmitter shall permit field programmable damping to smooth output in turbulent flow conditions, and programmable rejection time to disregard false signals from rain, wind, floating objects and spurious echoes.
  6. Transmitter operating temperature shall be from -5° to 140°F (-20° to 60°C). Transmitter shall contain a thermostat-controlled enclosure heater for condensation protection below 30°F (-1°C).
  7. Have a built-in 50,000 point data logger with USB and RS232C output and connecting cables. Data logger shall support time and date-stamped logging and display daily flow reports including total, average, minimum, maximum and times of occurrence.
  8. Include Windows software for data log retrieval, graphing and export.
  9. Transmitter shall have an isolated 4-20mA output into a 1000 ohm maximum load and user-selectable 0-5V output.
  10. Provide 3 relay contacts rated 5 amp SPDT programmable to operate a remote totalizer, a sampler, high-low flow alarm plus echo loss alarm.
  11. Provide a 4-digit LCD display scaled in user-selected engineering units and visible without opening the Transmitter enclosure.
  12. Provide a 16-digit alphanumeric display for calibration menu, running totalizer, flow reports, or error message display of echo loss or other fault conditions.
  13. Transmitter shall be housed in a wall-mount, watertight NEMA4X (IP66) enclosure with hinged, clear cover. Mounting hardware shall be included.
  14. Transmitter Displays indicating flow rate, units of calibration, maximum flow rate and flow totalizer shall be visible without opening cover.
  15. Transmitter electronics shall be surge protected on AC power input, sensor, 0-5V and 4-20 mA output.
  16. Transmitter power input shall be 115VAC 50/60Hz with power consumption of 6.2 Watts or less.


  1. Electronics enclosure shall include an Intrinsic Safety Barrier. Sensor, connecting cable and junction boxes shall be rated intrinsically safe to Class I,II,III, Div. I,II, Groups C,D,E,F,G.
  2. Have a thermostat controlled Enclosure Heater for transmitter operation at temperatures below freezing.
  3. Have manufacturer's recommended Enclosure Sunscreen to permit electronics enclosure mounting in direct sunlight.
  4. Have manufacturer's recommended Sensor Sunscreen to permit temperature-compensated sensor mounting in direct sunlight.
  5. Have manufacturer's recommended sensor mounting stand.
  6. Transmitter power input shall be 200-260VAC 50/60Hz with maximum power consumption of 6.2 Watts or less.
  7. Transmitter power input shall be 9-36VDC with minimum power consumption of 2.1 Watts.


Open Channel Flow Monitor shall be Greyline Model OCF 4.0 and warranted against defects in materials and workmanship for one year.