Contrec 515 – FN01

  • Net Oil Computer

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

The 515 FN01 Net Oil Computer  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 Contrec 515-FN01 Net Oil Computer 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 received 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

Displayed Information

The front panel display shows the current values of theinput variables and the results of the calculations. A list of the variables for this application and their type (total or rate) is shown at the end of this document.The instrument can be supplied with a real-time clock for data logging of over 1000 entries of the variables as displayed on the main menu.


There are two communication ports available as follows:
• COM-1 RS-232 port
• COM-2 RS-485 port (optional) or Ethernet (optional)
All types of ports can be used for remote data reading, while RS-232 and RS-485 serial ports can be used for printouts and for uploading and downloading of the application software to the instrument.

Isolated Outputs

The opto-isolated outputs can re-transmit any main menu variable. The type of output is determined by the nature of the assigned variable.  Totals are output as pulses and rates are output as 4-20 mA signals. One output is standard, a second output is available as an option.

Relay Outputs

The relay alarms can be assigned to any of the main menu variables of a rate type. The alarms can be fully configured including hysteresis. Two relays are standard with two additional relays available as an option.

Software Configuration

The instrument can be programmed to suit the particular application needs and the flexible I/O can be assigned as required. Program settings can be changed either via the front panel (depending on assigned access levels) or viathe 500 Series Program Manager (500-PM software).

For more information on Contrec Flow Computers, please click on the link.