Yokogawa Low Pressure Flow Meter

The EJX-A series is Yokogawa's premium performance line of DPharp transmitters. Released in 2004, it offers the performance and stability needed in demanding applications. The EJX-A series performance makes it the thoroughbred of the DPharp family of pressure transmitters.

The EJX115A is Differential Pressure (DP) Flow Transmitter in the series optimized for low flow applications with the addition of an Integral Flow Orifice (IFO) assembly.

The EJX115A is designed to measure accurately, transmit quickly, and do it reliably over time.

  • Accurately: ±0.04% Square Root Output Accuracy
  • Quickly: 90 ms Response Time
  • Reliably: ±0.1% per 15 years Stability (DP)


EJX115A Low Flow Flowmeter

The low flow transmitter EJX115A is a differential pressure (DP) flow transmitter (Secondary Element) assembled with an integral orifice (Primary Element). The EJX115A is engineered to provide excellent low flow measurement. It outputs a 4 to 20 mA DC signal corresponding to the measured flow. Its highly accurate and stable DPharp pressure sensor also measures static line pressure. The static pressure can be displayed on the integral indicator or remotely monitored via digital communications. Other key features include quick response, remote set-up using communications, diagnostics, and optional status output for pressure high/low alarm. The multi-sensing pressure sensor technology provides an optional advanced diagnostic function to detect such abnormalities as an impulse line blockage. HART (5 or 7), BRAIN, FOUNDATION Fieldbus, and PROFIBUS PA protocol types are available. All EJX-A series models in their standard configuration, except the FOUNDATION Fieldbus and PROFIBUS PA types, are certified by TÜV as complying with SIL 2 for safety requirement.

Low Flow Transmitter


The EJX115A uses an IFO bore to generate the differential pressure.

IFO Assembly

Low Flow Transmitter

Bore Sizes

Bore sizes avilable are 0.508mm, 0.864mm, 1.511mm, 2.527mm, 4.039mm, or 6.350mm.

One is included with each EJX115A, or an entire set can be purchased separately.

The actual bore used has to be determined based on the process data.

Contact your Yokogawa representative for more information.

Low Flow Transmitter


The EJX115A uses the EJX110A differential pressure transmitter as the secondary element.

Low Flow Transmitter

Digital Performance

Using the latest in semiconductor design and manufacturing technology, Yokogawa designed the DPharp digital sensor to deliver improved performance and reliability over the competitor's old technology analog sensors. Although analog sensors are suitable, the advanced DPharp sensor outperforms even the best analog sensor. A Yokogawa transmitter with the DPharp digital sensor gives the consistent, reliable, accurate measurement needed.

Poor Performance = Lost Money

Accuracy Under All Operating Conditions

Yokogawa's DPharp sensor can measure the differential pressure (DP), static pressure (SP), and sensor temperature from a single sensor. Given these three pieces of process data, the EJX110A transmitter can compensate the DP measurement for Temperature Effect and Static Pressure Effect in real time. This compensation is referred to as Dynamic Compensation and improves the DP measurement accuracy. Competitor's analog sensors can only measure DP and Sensor temperature. So, theirs can compensate for temperature Effect; but, since the SP measurement is missing, it cannot compensate for Static Pressure Effects.

Poor Performance = Lost Money

Low Flow Transmitter

Low Flow Transmitter

Stability Under All Operating Conditions

To some degree, all pressure sensors on the market provide stable measurement with variations in temperature and static pressure. However, what happens when the sensor is over-pressured (pressure > sensor Upper Range Limit (URL)) - like occurs when a manifold is incorrectly sequenced during start-up or shutdown? Alternatively, a process upset? Analog sensors are damaged during these events requiring the transmitter to be recalibrated to return to the accurate operation or even replaced. The EJX110A can withstand overpressure events up to 3,600 psi. Once it returns to normal operating pressure (pressure < URL of the sensor), the transmitter returns to operation within the defined accuracy and stability specifications - no need to recalibrate.  The Yokogawa DPharp sensor has a more significant operational envelope compared to an analog sensor.

Poor Performance = Lost Money


EJX115A Specifications

The EJX115A measures and transmits a primary and secondary variable. The Primary variable is the differential pressure generated by the IFO. The analog output of this variable can be set to Linear mode (for sending to a flow computer) or Square Root mode (to provide volumetric flow measurement). The Secondary variable is the static line pressure. It can be set to measure off the high-pressure side or the low-pressure side of the IFO as either an absolute or calculated gauge pressure measurement. The secondary variable is transmitted via the digital protocol. A flow computer can use the information.

Measurement Types
Primary Variable Volumetric Flow (Differential Pressure)
Secondary Variable Static Pressure
Reference Accuracy
Primary Variable ±0.04% of Flow Span (Square Root Output)
Secondary Variable ±0.2% of Static Pressure Span
Response Time
Primary Variable 90 ms (M and H Capsule)
150 ms (F Capsule)
Secondary Variable 360 msec
Long Term Stability
Primary Variable ±0.1% of URL per 15 years (DP)
Primary Variable F Capsule: 10:1 (DP)
M Capsule: 50:1 (DP)
H Capsule: 10.5:1 (DP)
Specification Conformance
EJX-A Series ±3σ

EJX115A Capsules (Primary Variable)

Low Flow Transmitter

Low Flow Transmitter

Low Flow Transmitter

Graphics not to scale

Low Flow Transmitter

Meter Run

Yokogawa can custom build flanged meter runs of any length and ANSI rating. Meter runs are available with a Yokogawa 3-valve or 5-valve manifold.

Contact your Yokogawa representative for more information.



The EJX115A low flow transmitter can use the Yokogawa IEC 61518 compliant 3-valve or 5-valve manifold.

Low Flow Transmitter

Low Flow Transmitter


Yokogawa manufactures a communicator for your needs. Yokogawa communicators are available for BRAIN Protocol, HART Protocol, FOUNDATION Fieldbus, PROFIBUS PA, ISA100, or MODBUS. All our communicators are compatible with Yokogawa products as well as other products on the market.


Yokogawa offers a range of loop powered and FOUNDATION Fieldbus remote indicators that can be used to locally monitor data from field instruments installed in difficult to access locations.

Low Flow Transmitter

Low Flow Transmitter

Pressure Calibrators

The Yokogawa CA700 Portable Pressure Calibrator uses the same DPharp sensor technology as our EJA-E and EJX-A series pressure transmitters. It provides an accurate and efficient calibration and verification tool for any pressure transmitter or other type of field device.

Communication Converters

Yokogawa offers communication converters by Moore Industries to convert secondary HART protocol variables to a 4 to 20 mA analog signal or all the HART variables to MODBUS RTU.

Low Flow Transmitter



Pressure - Low Cut Output Signal With some applications, the output signal can be erratic as the input nears the zero point. One of the most common applications with this issue is differential pressure flow measurement. A differential pressure (DP) ...
Edition 1
Meter Run Yokogawa's EJA115E and EJX115A are low flow volumetric differential pressure flow meters. They employ a simple integrated IFO to generate differential pressure. The unit requires a certain number of upstream and downstream pipe diamete...
Edition 2
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Discover the safety features built-in to the Yokogawa digital pressure sensors (DPharp).

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Is it true that 4-20 mA HART will be phased out in the near future? Is a transducer equal to a transmitter? Tune in to hear the debunking of these myths.

2D/3D Configurator

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