Greyline Instruments” OCF 4.0 Open Channel Flow Monitor uses a non-contacting ultrasonic sensor to measure wastewater flow through flumes or weirs. It features a built-in data logger with on-screen flow reports plus Windows software to retrieve, display and graph flow reports in fully customizable formats. Other features include isolated 4-20mA, 0-5V, USB and RS232 outputs, three control relays, a flowrate display plus a 10-digit totalizer. Calibration and selection of flume or weir are made through the built-in three-button keypad and menu system. Calibration set-up is password protected and flow data and totals are stored in the event of power interruptions. Temperature compensation is automatic and accuracy is +/-0.25 percent. Options include intrinsically safe sensors, an enclosure heater, and 9-36VDC power input.