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Y-Flow™ FFC Orifice Flow Computer

Yokogawa’s low power orifice flow computer offers flexible I/O points and superior data collection with a wide range of connectivity options. By combining Yokogawa’s EJX910A multivariable transmitter (DP and SP) and Y-FlowTM RTU, you can rest assured that your critical process will never lose a beat. Whether you are measuring gas flow for custody transfer or need wellhead control and monitoring, Yokogawa offers both the performance and stability required in the most rigorous environment.

  • API Chapter 21 compliancy
  • AGA 3 & 5 capability
  • AGA 8 (Detailed & Gross Methods I & II) & NX-19
  • Single and Bi-Directional (total vol. + avg. vol.) measurement
  • Multiple run capability
  • Solar panel with battery back-up or AC powered with battery back-up
  • Wide array of wireless connectivity options (Cellular, wireless radio and satellite)
  • Pole mount, wall mount or direct mount options
  • Wide variety of enclosure size options

With over 100 years of research and development in flow and data acquisition technology, Yokogawa’s Y-FlowTM product line provides unparalleled performance and reliability. The Y-FlowTM product family consists of Yokogawa’s Field Flow Computer (FFC) and Remote Terminal Unit (RTU) products. This technology turns complex gas flow calculations and remote control applications into a simple, flexible and expandable platform through pre-programmed applications. Its low power consumption and rugged design assures reliable operation in the harshest environments. From gas wellhead monitoring and control to transport and distribution, Yokogawa’s Y-FlowTM provides timely, accurate and reliable measurements that will increase your bottom line.


Pre-configured Applications

AGA 3 Orifice Measurement Tube/Run Switching
AGA 5 Fuel Gas Calorific Measurement Turbine Meter Profiling
AGA 8 Gas Density Measurement (Detailed & Gross Methods I & II) Compliance Alarming
AGA-7 Measurement of Natural Gas by Turbine Meter Tank Level Monitoring
AGA-9 Measurement of Gas by Multi-Path Ultrasonic Meters (using AGA-7) V-Cone Measurement
AGA-11 Measurement of Natural Gas by Coriolis Meter (using AGA-7) Plunger Lift
NX-19 Gas Density Measurement --
Emergency Shutdown --
Valve Control --

Wellpad Monitoring & Control

Yokogawa’s Y-FlowTM RTU is an effective and precise remote management controller that allows for maximized production while ensuring the production process is safe and reliable. By taking inputs from various instrumentations, the RTU will process and monitor the data through pre-programmed or user-designed applications. The data is logged, stored and transmitted to a host/SCADA system via Ethernet (Modbus Serial, Modbus TCP) or wireless communication protocols.

Gas Measurement

Yokogawa’s Y-FlowTM FFC provides timely, accurate and reliable measurements anywhere, anytime. By combining the Y-FlowTM with Yokogawa’s state-of-the- art coriolis, vortex and multivariable meters, accurate gas measurements are easier than ever. From orifice flow to steam measurement, Yokogawa’s Y-FlowTM FFC provides superior accuracy and reliability that ultimately reduces CAPEX and increase profit.

Gas Control

In an industry where safety and reliability is priority, Yokogawa’s Y-FlowTM provides the control and peace of mind for operators and engineers alike. From emergency shutdowns to valve control and positioning, Yokogawa’s Y-FlowTM is there to ensure the process is safe and sound.

Yokogawa EJX910A Multivariable Transmitter Accuracy Specifications

Specifications for the EJX910A are condensed for the purpose of this document. Please see GS01C25R01-01EN for more detailed information.

The EJX910A uses the established DPharp pressure sensor technology that allows for simultaneous measurement of differential pressure and static pressure (absolute or gauge) from one sensor. Out of all the Yokogawa pressure transmitters, the EJX910A has the best accuracy for combined DP and SP measurement, which makes it an excellent choice for flow calculations with a RTU.

DP inH20 SP psia
M Span 2 to 400 145 to 3600
Range -400 to 400 0 to 3600
H Span -10 to 2000 145 to 3600
Span -2000 to 2000 0 to 3600

Reference Accuracy
(Includes terminal-based linearity, hysteresis, and repeatability)

  • DP Up to ±0.04% of span standard
  • SP ±0.1% of span (Absolute)

Long Term Stability (All normal operating conditions, including overpressure effects)

  • DP ±0.1% of URL per 10 years Turndown
  • DP 200:1
  • SP 25:1

FFC Technical Specification

Input Power Supply

  • Input Power: 7-30 VDC
  • One (1) power supply/rechargeable battery input with screw terminals
  • Integrated solar panel charger supporting up to 20W solar panel

Power Monitoring and Battery Backup

  • Supply voltage monitoring through A/D with low supply voltage alarm
  • 3.6 VDC lithium ion battery backup for database, history, audit trail, time/date and RAM
  • 10W on board battery charger, 100W maximum
  • 32AH solar panel battery (optional)


  • Processor: ARM Dual Core 32-bit
  • Flash Memory: 32 megabit
  • SRAM Memory: 32 megabit
  • A/D: 16-bit with optional HART filtering

Display Options

  • Single line alphanumeric display
  • 4 line alphanumeric display with push button keypad

Operating Temperature

  • -40C to 70C (-40F to 160F)

Communications Options

  • Standard: Two (2) Serial RS-232/RS-485
  • One (1) Ethernet Port, (1) USB Host Port, (1) USB Device Port
  • Wireless Communication: Cellular (CDMA/GSM), Radio (spread spectrum licensed & unlicensed frequency), Satellite (LEO &GEO)
  • Protocols: MODBUS TCP/IP, MODBUS Serial, ERC Hex ASCII (native)

Input and Output (I/O)

  • Analog Inputs: Four (4) universal analog inputs, 0-5VDC or 4-20mA (Requires 250 ohm resistor)
  • RTD Inputs: One (1) temperature probe
  • Digital Input/Output: Two (2) form A/C pulse input, Two (2) form C relays, Two (2) DI, Two (2) DO


  • Field Manager

Optional Expansion Board Capability (9010449)

  • Two (2) Serial RS-232/RS-485
  • Four (4) universal analog inputs
  • One (1) analog output
  • One (1) RTD temperature probe
  • Two (2) form A/C pulse input
  • Three (3) DI, Three (3) DO
  • Opto 22 G4 Voltage Signal Conditioner


  • UL Class I, Div II Group A,B,C,D (pending)


  • 4 years limited warranty


Y-FlowTM Extender Board

In addition to the standard I/O offered on the processor board, the FFC and RTU have the capability to expand I/O count by adding the Y-FlowTM extender board. Furthermore, the extender board allows for Opto 22 G4 AC and DC input/output modules for applications that require switching loads such as DC relays, solenoids, motor starters, lamps and indicators.

Type Count
Serial RS232/RS485 2
Analog Inputs 4
Analog Outputs 1
RTD (Temp Probe) 1
Pulse Inputs 2
Digital Inputs 3
Digital Outputs 3
Opto 2 G4 Slots 2

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