Pressure Transmitters

What is a Pressure Transmitter?

Pressure transmitters are employed for gauging the pressure or level of liquids and gases within industrial settings. By providing accurate and reliable data for process control, pressure instrumentation enhances product quality, reduces total cost of ownership, and increases plant uptime. The pressure transmitters deliver high reliability across multiple process conditions, eliminating numerous application challenges thanks to the advanced DPharp pressure sensor technology. Learn more about the features and benefits of our DPharp pressure transmitters.

Optimize Plant Operations with Fewer Resources

Yokogawa Industrial Pressure TransmittersYokogawa pressure transmitters do more than just provide accurate and reliable data for process control. DPharp pressure instrumentation helps achieve enhanced product quality, reduced total cost of ownership, and increased plant availability. Engineered with DPharp pressure sensor technology, our pressure transmitters deliver high reliability across a range of process conditions, eliminating numerous application challenges.


What Are the Benefits of Pressure Transmitters?

With improved digital performance, measurement accuracy, and overpressure protection, DPharp pressure transmitters contribute to enhanced product quality.

Digital Performance

Other pressure sensor technologies require an analog-to-digital conversion before the signal can be processed, introducing additional errors. In Yokogawa’s pressure transmitters, the DPharp sensor directly outputs a digital signal, eliminating the need for analog-to-digital conversion and improving performance.

Accuracy Under All Operating Conditions

Fluctuations in static pressure and temperature cause errors in differential pressure measurement. Analog sensors can only measure DP and sensor temperature and therefore can only compensate for temperature effect.

Yokogawa’s DPharp digital pressure sensor measures the differential pressure (DP), static pressure (SP), and sensor temperature from a single sensor. Given these three pieces of process data, our differential pressure transmitters compensate the DP measurement for temperature effect and static pressure effect in real-time. This compensation is referred to as Dynamic Compensation and improves DP measurement accuracy.

Learn more about Dynamic Compensation.

What Happens When a Transmitter Sensor Is Exposed to Overpressure?

Overpressure events such as incorrect sequencing of a manifold during start-up or shutdown and process upsets can damage analog sensors, requiring the transmitter to be recalibrated - or even replaced - in order to return it to normal operations.

The simple, robust design of Yokogawa's DPharp pressure sensor makes it less susceptible to overpressure events. A mechanical system within the transmitter provides additional overpressure protection by equalizing the excessive pressure before it reaches the sensor. Once it returns to normal operating pressure, the transmitter returns to operation within the defined accuracy and stability specifications with no need for recalibration. The Yokogawa DPharp sensor has a more significant operational envelope compared to an analog sensor, allowing you to run your control loop at your desired set-point regardless of process conditions.

field instrumentation white paperHow to Reduce Total Cost of Ownership for Field Instrumentation?

DPharp pressure transmitters are certified to high safety standards as well as international standards and require fewer calibrations. Multi-sensing and universal mounting features eliminate the need to manage multiple transmitters, reducing total maintenance costs.

Safety as Standard

Pressure safety certificateAt Yokogawa, safety is never an option. All Yokogawa pressure transmitters are designed and certified to IEC61508:2010 Parts 1 through 7 and IEC61511:2004 Parts 1 through 3 by Exida® and TÜV Rheinland®.

As standard, all Yokogawa transmitters are certified for single transmitter use in SIL2 safety applications and dual transmitter use in SIL3 safety applications. The same transmitter can be used for both process control and safety applications. Managing two separate transmitter models is no longer necessary, reducing spares inventory and simplifying daily operations.

Extended Calibration Check Intervals

When devices are initially installed, they operate at peak performance, but what happens after they are running under various process conditions and poorly managed or maintained?

Changing operating conditions can cause transmitters to drift to the point where they are no longer able to make accurate measurements for the process loop they are installed in, resulting in poor quality or an impact to product yields. This requires a calibration check interval to ensure you’re operating within desired error limits.

The DPharp sensor has an unconditional long-term stability guarantee of ±0.1% up to 15 years under all operational conditions, reducing calibration frequencies. As you gain experience with these transmitters, the interval between calibration checks is extended. Long-term this can help reduce your maintenance cost by up to 34%. Spend your time where it is needed.

Independent Third-Party Verification

With the rapid globalization of markets, numerous international standards and approvals are becoming necessary. Yokogawa pressure transmitters have acquired various international certifications including FM, CSA, ATEX, IECEx, INMETRO, KOSHA, EAC, and NEPSI.

Logos of agencies certifying Yokogawa pressure transmitters

Multi-Sensing in DP Applications

Other suppliers' transmitters use analog sensors, which require two separate transmitters for any application that needs both differential pressure (DP) and static pressure (SP) measurements.

Yokogawa's differential pressure transmitter features our multi-sensing DPharp sensor, which can measure both process variables (DP and SP) with a single transmitter, saving you the cost of a gauge pressure transmitter as well as the manifold, piping, wiring, I/O, construction, and engineering man-hours associated with it. With our DP transmitter, there are fewer devices to manage, maintain and calibrate, lowering overall lifecycle costs.

Standard Communication Protocol

Yokogawa transmitters support all industry-standard field device communication protocols. Interoperability and interchangeability can be ensured. Use all the same tools and work procedures as before. Yokogawa transmitters are available with analog 4 to 20mA signal with either BRAIN® digital protocol or HART® digital protocol; Low Power analog 1 to 5 VDC with HART® digital protocol; or all digital FOUNDATION® Fieldbus or PROFIBUS® PA protocol.

Universal Mounting

Pressure transmitters on the market have several different flange configurations depending on the medium being measured (gas or liquid). This requires plants that process both mediums to maintain a stock of both types of configurations.

Yokogawa's pressure transmitters offer a universal mount that can be configured to handle either gas or liquid; reducing your inventory of replacement transmitters.

How Are Pressure Transmitters Built?

DPharp pressure transmitters are engineered to withstand the harshest process conditions, featuring a rugged construction design and less susceptibility to overpressure events for a longer-lasting transmitter.

Rugged Construction

Harsh environments can reduce the life of your instrumentation, causing maintenance issues and plant downtime. Yokogawa’s ruggedly constructed pressure transmitters feature a four-bolt pressure-retaining design, Teflon® coated 316L stainless steel flange gasket, and a dual seal certified to ANSI/ISA 12.27.01. These design features extend the life of your transmitter, increasing plant availability.

How Does Overpressure Protection Work?

During improper manifold sequencing, startup and shutdown conditions, or process upsets, overpressure can occur. The simple, robust design of Yokogawa's DPharp pressure sensor makes it less susceptible to overpressure events. A mechanical system within the transmitter provides additional overpressure protection by equalizing the excessive pressure before it reaches the sensor. Once stable process conditions return, these features enable the transmitter to return to normal operation within the published specifications.

Local Indicator

Easy to read indicator provides all the information you need. The indicator can display any of the variables measured (DP, SP, Capsule temperature); alarm codes with short text; and a sweeping bar graph to give a graphical representation of the process. Fully programmable, the indicator is customizable for your needs. Unlike other suppliers' transmitters, the indicator is not driven off the 4 to 20mA analog signal, but, exists as a separate circuit allowing the display to operate independently from the output signal.



The primary function of a utility boiler is to convert water into steam to be used by a steam turbine / generator in producing electricity. The boiler consists of a furnace, where air and fuel are combined and burned to produce combustion gases, and a feedwater tube system, the con- tents of which are heated by these gases. 


Yokogawa DPharp EJA/EJX Pressure transmitters do not need frequent re-zeroing due to superior long term stability, it contributes to reduce maintenance time.

Application Note

Hydrogen is the simplest and smallest atomic element. Water, acids, bases, and the immense family of organic compounds all contain hydrogen. Even though hydrogen is not corrosive, it can cause problems for pressure transmitters through Hydrogen Permeation.


DPharp performance in boiler drum level measurement applications is superior to metallic capacitance type pressure transmitters. Improved performance can be attributed to the unique resonant silicon sensor design with dual resonators.


Download this eBook and learn:

  • The basic physics of pressure
  • Different types of pressure sensors
  • Features of pressure transmitters
  • Pressure transmitters communications standards
  • Key characteristics of pressure
  • Common types of diaphragm seals
Response Time Response Time is the amount of time (in seconds) it takes for the output signal to reach 63.2% of an instantaneous full-scale pressure change. Pressure transmitters respond to pressure changes as a first-order system; therefore, derive...
Edition 03
Housing Color Yokogawa's high anti-corrosion coating is available in any color requested. However, the color must have a Munsell number to ensure a proper match. The body or amplifier cover or terminal block cover (or a combination) can be coat...
Edition 03
Local Parameter Setting We have all run into this problem one time or another; you were out in the process area when you realized you need to make a change to a transmitter, but your Hand Held Communicator (HHC) is back at the instrument shop! Your ...
Edition 2
Adapter Kit Yes, with Yokogawa's coplanar-to-IEC adapter kit, the coplanar manifold is reused. The kit enables the easy replacement of a coplanar transmitter by a Yokogawa EJA-E or EJX-A Series pressure transmitter without changing...
Edition 02
Write Protect Yokogawa pressure transmitters have Hardware (Switch) and Software (Password) write-protect functions. The transmitter can be set-up to use either or both to secure the transmitter. Hardware All Yokogawa pressure transmitters ha...
Edition 02
Uni-Delta (YA Series) Pressure Transmitters The Uni-Delta (YA Series) pressure transmitters are no longer available. The EJA-E series of DPharp pressure transmitters replaced the series when discontinued in 2006. Yokogawa Technical Sales Support Tec...
Edition 2
Languages All of Yokogawa's documentation is available in English and Japanese. Select other languages are also available. If you have a need for a document in another language, contact your local Yokogawa representative. ...
Edition 2
Integral Display Yokogawa offers upgrade kits to allow for “blind” transmitters to be upgraded in the field. These kits use the same multi-function displays as those transmitters manufactured with integral indicators and include all...
Edition 2
Nationally Recognized Testing Lab Approvals (NRTL) Yokogawa pressure transmitters are sold worldwide; therefore, they have different agency approvals to meet global and local testing requirements. These approvals include, but not limited to:  ...
Edition 02
"Off-line" Diaphragm Seals Yokogawa offers diaphragm designs that allow for a different diaphragm size than the available process connection. This type of seal is commonly referred to as an 'off-line' seal. These ...
Edition 02
Hand-Held Communicator A Hand-Held Communicator (HHC) can interface with the transmitter from the control room, the transmitter site, or any other wiring termination point in the loop. To communicate, the tool must be connected to the signal l...
Edition 01
Rotating the Housing (Transmitter Section) The transmitter section of the EJA-E or EJX-A series pressure transmitters can be rotated approximately 360° and fixed at any angle within this range. (The direction of the rotation is dependant on...
Edition 02
Changing the Direction of the Integral Indicator An integral indicator can be installed in the following three directions. Follow the instructions in section 8.4 for removing and attaching the integral indicator. Procedure Remove the cover. ...
Edition 02
SIL 2 Certification At Yokogawa, safety is never an option. All Yokogawa EJA-E and EJX-A series pressure transmitters with BRAIN or HART protocol communication are designed and certified to IEC61508:2010 Parts 1 through 7 and IEC61511:2004 Part...
Edition 02
EJA-A to EJA-E Crossover The Yokogawa EJA-A series is the original DPharp pressure transmitter developed during the early 1990s. It was discontinued and replaced by the EJA-E series in the mid-2010s. If your EJA-A series needs to be replaced, Yokoga...
Edition 02
Status Output (Option code: /AL) A unique feature of the EJX-A series is the Status Output option (/AL). This option provides an on/off output signal separate from the 4 to 20 mA analog signal. The on/off output signal is driven off the user-configu...
Edition 02
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Extend your differential pressure transmitter's range with affordable isolation solutions, shielding it from extreme process temperatures and corrosive fluids.

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Discover the safety features built-in to the Yokogawa digital pressure sensors (DPharp).

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Join Applications Engineer Michael Keller as he guides you through the steps for connecting the EJX910 Modbus with the USB Modbus converter.


How much do you know about pressure transmitters? Are you accurately, quickly and reliably measuring pressure? Ultimately, the drive of any good pressure transmitter is to get an accurate, reliable pressure measurement to the data user quickly. This video gives you the answers to your basic questions about pressure and pressure transmitters.


Yokogawa’s Local Parameter Setting (LPS) featured in our Pressure Transmitters helps you set 9 parameters without the use of a handheld communicator.


Join this webinar to better understand which manifolds you should use for specific applications and conditions. You will learn:

  • A brief history of manifolds
  • An overview of the different types of manifolds that are available
  • The advantages, disadvantages, and application considerations you should consider when selecting a manifold


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