Contrec 515 Natural Gas Flow Computer (GN16)

Natural gas and coke-oven gas custody transfer, using a DP volumetric meter, single or stacked transmitters, needs gas density and compressibility corrected for the actual gas composition, not just a fixed factor. The Contrec 515 GN16 Natural Gas Flow Computer is built for this.

It runs standard DP flow equations while accounting for the primary element’s own reference calibration conditions, and resolves density and compressibility using the SGERG method (AGA-8 Gross Characterization), which works well for gas networks where methane content and trace elements vary from batch to batch.

In actual application, this unit usually sits out on process plant rather than in a control room, so it comes in a weatherproof IP65 housing. It also has an adjustable 8-24V DC sensor excitation supply, isolated 4-20mA loop retransmission, and dual RS-232/RS-485 Modbus RTU ports for integration into plant automation networks.

Before we quote this, we would normally check your DP transmitter range (single or stacked), your gas composition data, and your line pressure and temperature.

Hope this helps.

Contrec Model 515 GN16 Technical Specifications
● POWER SECTION
Power Supply Options115 Vac ±15% standard (Optional: 230 Vac ±15% layout via model code E)
12 to 28 Vdc external field loop power input
Transducer Power OutputAdjustable 8 to 24 Vdc sensor excitation voltage regulated via software controls; maximum continuous current capacity up to 50mA.
Memory RetentivityNon-volatile flash memory permanently stores gas totalizers, data logs, hardware constants, and system configurations during full plant power failure events.
● INPUT SECTION
Differential Pressure InputsSingle or dual stacked analog differential pressure input channels.
Configurable Signal Formats: 4 to 20 mA current loops, 0 to 5 Vdc, or 1 to 5 Vdc voltage signals.
Signal Processing: Active filtering, programmable low-flow cutoff boundaries, and linear extraction.
Compensation Analog InputsAnalog Temperature Input: RTD (Pt100) or linear 4 to 20 mA process loop.
Analog Pressure Input: 4 to 20 mA active linear transmitter input.
● OUTPUT SECTION
Analog Retransmission LoopFully isolated 4 to 20 mA DC current loop retransmission output channel with programmable range scaling.
Digital Pulse RetransmissionOpen collector transistor output featuring software-defined volumetric scaling factor and adjustable pulse width duration.
Serial InfrastructureRS-232 Port: Dedicated port optimized for direct PC terminal setup or local ticket receipt printing.
RS-485 Port (Optional): Multi-drop serial bus supporting robust long-distance plant networking.
Supported Protocols: Modbus RTU (Slave), standard Ticket Printer, and Contrec command-line protocols.
Local Display ScreenBacklit alphanumeric LCD display showcasing raw Volume, Volume Flowrate, Corrected Volume, Corrected Flowrate, Heat, Heat Flowrate, Mass, Mass Flowrate, Temperature, Pressure, and Compressibility Factor.
● PERFORMANCE
Calculation AccuracyBetter than ±0.01% of reading for all internal flow metrics, mass calculations, and mathematical SGERG density solutions.
Analog Transmittance PrecisionBetter than ±0.05% of full scale range under reference conditions.
Data Logging MatrixReal-Time Clock (RTC) event log memory block capturing over 1,000 entries for continuous process audit tracking.
● PHYSICAL
Mechanical Housing LayoutMolded field-mounting enclosure utilizing high-rigidity impact polymers (Optional flush panel mount, pipe track mount, or deployment within a heavy Ex410 explosion-proof housing).
Tactile Operator ArrayRobust elastomeric keyboard layout providing precise tactile user input feedback.
● STANDARDS CONFORMITY
Environmental SafeguardingStandard IP65 weatherproof frontal fascia shield protection.
*Note: Conformal PCB coating (Option C) is highly recommended to protect internal circuits from harsh humidity and ambient chemical corrosion.

Download Contrec 515 Natural Gas Flow Computer (GN16) information here

Datasheet: Contrec_515-GN16_Datasheet 
Manual: Contrec_515-GN16_Manual

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