• Non-contacting ultrasonic sensor
  • Accurate and verifiable
  • ±0.25% of range accuracy
  • Built-in 2-million point data logger
  • USB outputs to Flash memory sticks
  • Isolated 4-20mA/0-5V output
  • PZ15 level sensor, PVC, 8in deadband, 15ft range
  • 100-240VAC 50/60Hz power input
  • -5 to 140°F (-20 to 60°C) enclosure temperature
  • Standard electronics protection, no circuit board coating
  • Standard barriers not rated intrinsically safe
  • 25ft RG62AU coaxial sensor cable
  • 2 programmable control relays
  • Simple 5-key calibration with language selection
  • Password protected
  • On-screen flow reports
  • NEMA4X (IP 66) polycarbonate enclosure
    • Water & dust tight with shatterproof cover

What's in the Box

  • Level sensor
  • Coaxial sensor cable
  • Greyline Data Logger software for Windows
  • Installation and operation manual
  • NIST certificate


The Greyline Instruments OCF 5.0 open channel flow meter is designed to continuously monitor, display, totalize and data log flow through any flume or weir. Featuring an ultrasonic sensor that mounts above the flowing water, the OCF 5.0 will not obstruct the flow nor be prone to fouling.

The OCF 5.0 is easy to set up and operate. Use the built-in Keypad/menu system to select your flume or weir from the menu and to choose the measurement unit. Flow reports including minimum, maximum, average and total daily flow can be viewed directly on the backlit LCD display. The OCF 5.0 also includes a built-in, 2-million point data logger and flow reporting system. Connect a flash memory stick to the flowmeter's USB output to download log files and then view your data in graph and table formats with 'Greyline Logger' software.

The Greyline Instruments OCF 5.0 open channel flow meter has an isolated 4-20mA output which can transmit flow data to remote chart recorders or displays. The two control relays (upgradeable to six) 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 500ft (150m) of the sensor.





Please consider these optional accessories.


This product can be used in the following applications:

Here's how some of our customers use this product...

Gravity Feed Flow Monitoring

The Background: Our customer is a commercial orchard that needs to monitor the amount of irrigation water being diverted from a nearby stream.

The Problem: The stream water is gravity fed into a pipe that transports the water to the orchard. Most flow meters require a completely full pipe to accurately measure the flow, something which is not possible in most gravity feed applications such as this.

The Solution: The customer was able to deploy a Greyline OCF 5.0 open channel flow monitor with a Parshall flume, enabling them to accurately monitor water usage. Compatible with a wide variety of standard flumes and weirs, or user programmable for a custom application, the Greyline OCF 5.0 allows simple irrigation flow monitoring and the ability to log flow data or output to another device.