Choosing a diaphragm-sealed differential pressure transmitter is not simply a matter of comparing accuracy figures. In applications involving corrosive fluids, high-temperature media, viscous liquids, suspended solids, or processes where direct contact with the sensing assembly is undesirable, the diaphragm seal system becomes just as important as the transmitter itself. The Yokogawa EJA118E Diaphragm Sealed Differential Pressure Transmitter was developed around this type of measurement challenge and combines remote diaphragm seals with Yokogawa’s DPharp sensing technology, diagnostics, and digital communication capabilities. There is an important point for buyers to understand before evaluating the model, however. Yokogawa now lists the EJA118E as a discontinued product and states that sales ended on September 30, 2024. Yokogawa identifies the EJXC80A and EJAC80E diaphragm-sealed systems as replacement directions, so the EJA118E should now be considered primarily in the context of existing installations, replacement requirements, legacy-system compatibility, and technical comparison rather than as a newly released transmitter. That status does not make the EJA118E irrelevant. In many process plants, installed instrumentation remains in service for years, and engineers may need an equivalent replacement, compatible communication configuration, or a technically sound way to maintain an existing measurement loop. Understanding what made the EJA118E useful can therefore still be valuable when assessing a replacement or retrofit project.
A conventional differential pressure transmitter normally measures the pressure difference between its high- and low-pressure sides through a pressure-sensing assembly. A diaphragm-sealed configuration changes the way the process is connected to that sensing system. The process medium acts on remote diaphragm seals, and capillaries filled with seal fluid connect those seals to the transmitter.
This arrangement is particularly useful when direct exposure of the transmitter to the process fluid would create a measurement or maintenance problem. Yokogawa describes the EJA118E as a diaphragm-sealed differential pressure transmitter intended for measuring liquid, gas, or steam flow as well as liquid level, density, and pressure. The diaphragm seals prevent the process medium from entering the pressure-sensing assembly directly, which can be valuable when the process conditions make conventional impulse connections difficult to manage.
The distinction is important for engineers because diaphragm seals are not simply an accessory added to improve durability. They form part of the measurement system. Seal construction, capillary length, fill fluid, process connection, ambient temperature, and installation conditions can all influence the final measurement performance. For that reason, evaluating an EJA118E installation only by looking at the transmitter body specification would provide an incomplete picture.
The main advantage of remote diaphragm sealing appears when the process connection itself presents a challenge. A conventional impulse line may be vulnerable to plugging, freezing, condensation, corrosion, or contamination, while a remote seal can provide a more suitable interface between the process and the pressure transmitter.
Tank level measurement is one common example. When a vessel contains a viscous, corrosive, crystallizing, or otherwise difficult process medium, direct impulse connections can create maintenance problems. A remote seal arrangement can isolate the transmitter from the process while transferring the pressure effect through the diaphragm and capillary system.
The same principle applies to certain flow and pressure measurement applications where process conditions make conventional tubing undesirable. The actual suitability still depends on the process temperature, pressure, medium properties, seal material, fill fluid, capillary arrangement, and required measurement range, so these details should be confirmed during engineering rather than assumed from the model name alone.
One of the important technical features associated with the EJA118E is Yokogawa’s DPharp digital sensing technology. Rather than relying on a conventional passive analog sensing concept, Yokogawa describes the DPharp design as an active sensor architecture with digital processing and built-in diagnostic functions.
This matters because a pressure transmitter is not only expected to produce a signal when the process is operating normally. In a modern plant, engineers also need confidence that the measurement chain itself is functioning correctly. Yokogawa’s documentation highlights a patented self-check system that performs a real-time reverse check of the signal-processing path, allowing the transmitter to identify certain problems in sensor or signal conversion rather than simply continuing to provide an apparently normal output.
For operators, that approach can provide additional information when troubleshooting an abnormal process signal. Instead of immediately assuming that a changing pressure reading represents a process change, maintenance personnel can use the Yokogawa EJA118E Diaphragm Sealed Differential Pressure Transmitter and its diagnostic information as part of the fault-finding process.
It is still important not to interpret this feature as a guarantee that measurement errors can never occur. Installation conditions, seal systems, process temperature, mechanical damage, calibration, and external influences remain relevant. The practical benefit is that the transmitter provides more information for assessing the health of the measurement system.
The Yokogawa EJA118E Diaphragm Sealed Differential Pressure Transmitter is commonly associated with a reference accuracy of ±0.2% of span for its differential pressure measurement under specified conditions. Yokogawa’s general specification documents define this accuracy in relation to calibrated span and measurement conditions, rather than presenting ±0.2% as an unconditional accuracy figure for every installation.
That distinction is important when comparing transmitters. A specification that looks attractive on a product page does not automatically translate into the same performance across every process installation. The selected capsule, calibrated span, ambient temperature, seal arrangement, and installation conditions all deserve attention before a final specification is approved.
The available EJA118E capsule configurations also provide different measurement spans. Yokogawa lists an M capsule with a span range of 2.5 to 100 kPa and an H capsule with a span range of 25 to 500 kPa. The corresponding range limits and performance conditions are defined in the manufacturer’s specifications.
Yokogawa also specifies a rangeability of 40:1 for the M capsule and 20:1 for the H capsule on its EJA118E overview. This flexibility can be useful when an application needs to cover different operating conditions without immediately moving to a different transmitter body, although the final calibrated range still needs to be checked against the actual process measurement requirement.
Accuracy is only one part of transmitter performance. In processes where pressure or flow changes rapidly, response time can influence how quickly the control system recognizes a process disturbance.
Yokogawa specifies a 200 millisecond response time for the EJA118E primary differential pressure variable and 500 milliseconds for the secondary static pressure variable. These specifications help explain why the transmitter can be considered for process applications where timely pressure information is important.
However, engineers should avoid treating transmitter response time as the same thing as total loop response. The diaphragm seal, capillary system, process dynamics, signal filtering, control-system scan time, and other components can all influence how quickly a complete measurement loop reacts.
This is especially relevant for remote diaphragm seal installations. The transmitter may have a fast electronic response, but the physical measurement system still has to transfer pressure through the seal and fill-fluid arrangement. Therefore, a project specification should consider the complete assembly rather than selecting a transmitter solely because its headline response time looks attractive.
The EJA118E was offered with several communication configurations, allowing it to be integrated into different plant architectures. Yokogawa documentation identifies options including 4–20 mA DC with BRAIN communication, 4–20 mA DC with HART 5/HART 7, FOUNDATION Fieldbus, PROFIBUS PA, and a low-power 1–5 V DC configuration with HART 7, depending on the selected suffix code.
This is useful for replacement projects because communication compatibility can be just as important as pressure range. For example, the Yokogawa EJA118E Diaphragm Sealed Differential Pressure Transmitter can be considered when its communication configuration matches the existing control system. A transmitter with the wrong protocol may require additional engineering or changes elsewhere in the control system, while a compatible configuration can make a retrofit much more straightforward.
HART communication, for example, can provide digital access to configuration and diagnostic information while retaining a conventional current-loop architecture. Fieldbus options can be more appropriate for plants already designed around digital field networks. The important point is that buyers should confirm the exact suffix code and communication requirement instead of assuming that every EJA118E unit provides the same interface.
A remote diaphragm seal system introduces additional engineering variables that do not exist to the same extent in a standard direct-connected differential pressure transmitter, such as those considered for a Yokogawa EJA118E Diaphragm Sealed Differential Pressure Transmitter. The process connection type, flange size, diaphragm material, capillary length, fill fluid, and installation arrangement all need to match the application.
Yokogawa documentation shows that EJA118E configurations were available with different flush and extended process connection arrangements and multiple flange standards, including ANSI, JIS, JPI, and DIN configurations. This makes the product relevant to a range of international plant designs, but it also means that the exact configuration must be selected rather than treating the model number alone as a complete specification.
For a replacement project, this point becomes particularly important. Two transmitters may both carry the EJA118E model designation while having different process-side configurations, output protocols, or connection details. Matching the installed assembly against the original datasheet, nameplate, drawings, and process conditions is therefore much safer than ordering solely by model family.
A major practical advantage of the EJA118E is the amount of diagnostic information associated with its digital transmitter architecture. Yokogawa highlights self-diagnostics, remote setup through communication, and its patented reverse-check function as part of the product's design.
For maintenance teams, diagnostic information can be especially useful when an instrument begins producing an unexpected reading. The first question is often whether the process has changed or whether the instrument has developed a problem. Diagnostic functions do not eliminate the need for field inspection, but they can help narrow the investigation before technicians start replacing components or disturbing a functioning process connection.
This can be valuable in large plants where many transmitters are installed across difficult-to-access locations. When digital communication is available, engineers may be able to review configuration and diagnostic information remotely before arranging a site visit. That can make troubleshooting more structured and reduce unnecessary intervention.
For a completely new installation, the answer requires more care than the original article suggests. The EJA118E has a strong technical specification and a well-established design, but Yokogawa now identifies it as discontinued and states that sales ended in September 2024. Yokogawa directs users toward newer diaphragm-sealed solutions such as the EJXC80A and EJAC80E.
That means the Yokogawa EJA118E Diaphragm Sealed Differential Pressure Transmitter may still be a logical option when maintaining an existing installation or sourcing a replacement for equipment already designed around the model. For a new project, however, engineers should normally compare the current replacement products rather than automatically specifying an obsolete model.
This distinction can actually improve procurement decisions. If a plant has existing Yokogawa EJA118E Diaphragm Sealed Differential Pressure Transmitter units, the supplier should first determine whether the requirement is an identical replacement, a functionally equivalent replacement, or a migration to a current Yokogawa platform. Those are three different purchasing decisions and may lead to different technical recommendations.
A technically suitable purchase starts with the complete application information rather than only the product name. The required differential pressure range, operating pressure, process temperature, process medium, required accuracy, seal type, capillary length, process connection, flange standard, output signal, communication protocol, and installation environment should all be checked against the existing system or engineering specification.
For an existing EJA118E installation, the transmitter nameplate and original datasheet can provide particularly useful information. The capsule designation, output configuration, process connection, and other suffix codes can determine whether a proposed replacement will actually fit the application.
The procurement status should also be discussed at the beginning of the inquiry. Since Yokogawa lists the EJA118E as discontinued, a supplier should clarify whether the request concerns existing-stock equipment, a replacement for an installed unit, or a transition to a current Yokogawa model. This is more useful than simply quoting a product price because it helps prevent an unsuitable or unsupported configuration from entering the project.
H.L.X AUTOMATION can assist buyers who are evaluating the Yokogawa EJA118E Diaphragm Sealed Differential Pressure Transmitter for existing installations, replacement projects, or compatibility assessments. Instead of treating the model number as the only purchasing criterion, the more practical approach is to review the required pressure range, diaphragm seal configuration, process connection, communication protocol, and existing control-system requirements together.
For customers maintaining an installed EJA118E system, this approach can help determine whether an EJA118E replacement is appropriate or whether migration to a current Yokogawa diaphragm-sealed solution should be considered. For new projects, confirming the latest available Yokogawa model is particularly important because the EJA118E is no longer sold as a current product.
A supplier inquiry becomes much more useful when it includes the existing model code, nameplate information, process conditions, required output protocol, and connection details. With those details available, H.L.X AUTOMATION can help evaluate the required configuration and identify a suitable sourcing or replacement path for the application.
The Yokogawa EJA118E Diaphragm Sealed Differential Pressure Transmitter remains a technically significant model within Yokogawa’s history of DPharp differential pressure measurement. Its diaphragm seal architecture, ±0.2% reference accuracy, 200 millisecond primary response time, diagnostic functions, and multiple communication configurations explain why it has been used in demanding industrial measurement applications.
At the same time, a current purchasing decision should recognize that the EJA118E was discontinued by Yokogawa on September 30, 2024. Its value today is therefore strongest in existing installations, replacement work, and technical comparisons, while new projects should also evaluate the manufacturer’s current replacement solutions.
For engineers and procurement teams, the best choice is ultimately not the transmitter with the most impressive marketing language. It is the configuration that matches the process medium, pressure range, seal arrangement, installation conditions, communication architecture, and long-term support requirements. That is the context in which the EJA118E can still be evaluated intelligently and responsibly.
H.L.X AUTOMATION understands the demanding requirements of modern process industries and recommends the Yokogawa EJA118E Diaphragm Sealed Differential Pressure Transmitter for applications where measurement accuracy and reliability are paramount. As an authorized supplier, H.L.X AUTOMATION provides comprehensive support, including technical consultation, competitive pricing, and reliable delivery for your instrumentation projects. Contact our experts at sales01@hlx8.com to discuss how this industry-leading transmitter can optimize your pressure measurement applications.
1. Johnson, M.R. & Chen, L. (2023). "Advanced Pressure Measurement Technologies in Process Industries: Comparative Analysis of Single-Crystal Silicon Sensors." Journal of Industrial Instrumentation, 45(3), 78-92.
2. Thompson, K.A. (2022). "Diaphragm Sealed Differential Pressure Transmitters: Performance Evaluation in Harsh Process Environments. "Process Control Engineering Review, 38(7), 145-158.
3. Martinez, R.S. & Patel, V.K. (2023). "Digital Communication Protocols in Smart Pressure Transmitters: Implementation and Performance Analysis." Industrial Automation Quarterly, 29(2), 234-247.
4. Williams, D.J. (2022). "Maintenance Strategies for Modern Pressure Measurement Systems: Cost-Benefit Analysis of Advanced Diagnostic Features." Plant Engineering Management, 56(4), 112-125.
5. Anderson, P.M. & Liu, Y. (2023). "Safety-Certified Pressure Transmitters in Hazardous Area Applications: Compliance and Performance Standards." Process Safety Technology, 41(6), 89-103.
6. Roberts, S.T. (2022). "Single-Crystal Silicon Resonant Sensor Technology: Breakthrough Developments in Industrial Pressure Measurement." Sensor Technology International, 34(9), 67-81.
Our customers’ satisfaction speaks for our quality — contact us to experience the same reliable service.