Contrec 515 – FN01

Frequency Input Net Oil Flow Computer, Tailored for Mass Flow Meters

The 515 FN01 application calculates the net oil content in petroleum production fluids containing water. The net oil volume is corrected to a reference temperature according to ASTM D1250-04. The instrument uses the frequency signal from a mass flowmeter along with temperature and density analog inputs.

Reference densities for the oil and water are used in conjunction with live density and temperature values to determine the water cut.

The instrument is compatible with a wide range of flowmeter frequency outputs, including millivolt signals, reed switches, Namur proximity switches and pulse trains via its smart front-panel program selection.


The mass total and flowrate are derived from accurately measured frequency and the number of recieved pulses.

mass = pulses/k-factor

mass flow = frequency/k-factor

The oil volume correction calculations are based on the ASTM D1250-04 standard for the following products:

Crude Oils
Lube Oils
Refined Products