Yokogawa Pressure Transmitter Model Codes: What Information Do You Need?
A Yokogawa pressure-transmitter model code contains much more information than the product-family name. Depending on the EJA-E or EJX-A model, the complete code can define the measurement type, output signal, pressure range or capsule, wetted materials, process connection, installation arrangement, housing, electrical connection, display, mounting bracket and optional approvals or functions. This is why a request such as ‘replace an EJA110E’ is not enough to identify a like-for-like replacement. The full nameplate code and the actual process conditions should be reviewed together before an order code is confirmed.
REPLACEMENT GUIDE
Check Your Yokogawa Model Code
01 WHY IT MATTERS
Why the Full Model Code Matters
Two transmitters with the same base model can be mechanically or electrically different. One may use HART while another uses FOUNDATION Fieldbus. One may have a different measurement capsule, process connection or wetted material. The enclosure, cable entry, local indicator, mounting arrangement and hazardous-area option can also vary. In a brownfield replacement, these differences can determine whether the new instrument connects to the existing manifold, fits the available space, communicates with the control system and meets the site’s area classification.
The model code should therefore be treated as an engineering reference, not just a purchasing SKU. The safest replacement workflow is to capture the full code from the nameplate, identify the existing installation and then confirm whether the original configuration remains appropriate for the current process. A direct historical equivalent may not always be the best answer if the process or plant standard has changed.
02 / CODE ANATOMY
What Each Part of the Model Code Defines
Illustrative structure — the exact fields and their order depend on the base model and current General Specification.
1
Base model
Family & measurement role
2
Output / comms
HART, BRAIN, FF, PA
3
Span / capsule
Range family
4
Wetted materials
Diaphragm, flange…
5
Process connection
Interface & orientation
6
Housing & electrical
Entry, display
7
Mounting
Bracket, bolts
8
Option codes
Approvals & extras
Start with the Base Model
The first part identifies the transmitter family and measurement role. For example, EJA110E and EJX110A are differential-pressure transmitters, while other EJA or EJX models cover gauge pressure, absolute pressure, high-static differential pressure, draft range, level, diaphragm-seal or multivariable duties. The base model should therefore be interpreted together with the process function. If a plant tag says ‘PT’ but the existing device is actually being used for closed-tank level or DP flow, the replacement must preserve the complete application rather than only the tag description.
Output Signal and Communication
The suffix code normally identifies the communication/output family. Yokogawa General Specifications list options such as 4-20 mA with BRAIN or HART communication and digital FOUNDATION Fieldbus or PROFIBUS PA, depending on model. Some current EJA-E configurations also include low-power HART options. This field matters immediately in a replacement project because a transmitter using the wrong communication architecture may not integrate with the existing DCS, asset-management system or field wiring. Do not infer the protocol only from the appearance of the transmitter.
Measurement Span or Capsule
Pressure transmitters are offered with different sensor capsules or measurement ranges. The suffix code identifies the available span family, but final configuration still depends on the calibrated lower and upper range values. A replacement should therefore record both the model code and the configured range from the nameplate or device data. For differential-pressure transmitters, the static line pressure must also be checked. A transmitter can have a suitable DP span but still be unsuitable for the static pressure of the process.
Wetted Materials
Wetted-part codes identify materials exposed to the process, such as diaphragms, covers, flanges or other pressure-boundary components depending on the model. Material selection can be critical in corrosive, sour, high-purity or hygienic service. A replacement should not automatically move to a different material because it appears to be an ‘upgrade’. Compatibility with the actual fluid, plant piping specification and regulatory requirements must be confirmed.
Process Connection and Installation Arrangement
The order code can define process-connection details and installation orientation. On differential-pressure transmitters, this can affect impulse-piping arrangement and compatibility with an existing manifold. On gauge or absolute transmitters, the threaded or flanged process interface may determine whether the transmitter can be installed without piping modification. For brownfield work, photographs and dimensional information are valuable because a suffix-code match alone may not reveal every field constraint.
Amplifier Housing, Electrical Connection and Display
Housing and electrical-entry options affect cable-gland selection, conduit orientation, corrosion resistance and hazardous-area installation. The local indicator or display is another configurable element on many models. When replacing an instrument, note how the cable currently enters the housing, whether the operator needs a local display and whether the mounting orientation creates an access issue. These details are easy to miss when procurement focuses only on the base pressure range.
Mounting Bracket and Mechanical Options
Mounting brackets, bolts and other mechanical options can change by model and installation. A transmitter ordered without the required bracket may still be technically correct but impossible to mount as planned without additional field work. For manifold-mounted DP transmitters, also check the current manifold style, center spacing and whether the project intends to reuse it. Mechanical compatibility is one of the main reasons Tomarok recommends a nameplate photo and installation photo for replacement enquiries.
Optional Codes and Certifications
The final part of the model string can contain option codes for approvals, safety, materials, calibration, documentation, lightning protection, degreasing, tag plates or other features. The exact meaning varies by model and General Specification. Hazardous-area approvals are especially important: the required certificate should be defined by the site and country, then verified against the exact current model option. A legacy option code should not simply be copied if the current product uses a different approval structure.
03 REPLACEMENT CHECK
What to Send Tomarok for a Replacement Model Check
- Full manufacturer name and complete model code
- Clear photo of the transmitter nameplate
- Plant tag number
- Current calibrated lower and upper range values
- Measurement type: gauge, absolute or differential pressure
- Process medium
- Normal and design pressure and temperature
- Static pressure for DP applications
- Process connection and existing manifold information
- Wetted-material requirement
- Output / communication protocol
- Power supply
- Hazardous-area classification and required approval
- Photos of installation, wiring entry and manifold where possible
- Reason for replacement: failure, obsolescence, standardization, range change or process modification
04 EDGE CASES
What If You Do Not Have the Existing Model Code?
A new model can still be selected, but the process data becomes even more important. Start with the Yokogawa Pressure Transmitter Selection Guide and define gauge, absolute or differential pressure, range, static pressure, process medium, temperature, connection, materials, communication and area classification. If you know only that the plant currently uses an EJA or EJX transmitter, the EJA vs EJX comparison can help explain the family-level differences, but it should not be used to reconstruct a missing order code.
Do Not Copy a Model Code Without Checking the Current General Specification
Yokogawa model and suffix structures evolve as product families, communication protocols and approvals change. A code found in an old datasheet, ERP record or previous purchase order may refer to a discontinued or superseded option. The latest General Specification for the exact base model should therefore be used when decoding or rebuilding an order code. The model-code guide is intended to explain what information matters and what to collect before technical verification, not to replace Yokogawa’s official ordering tables.
Request a Yokogawa Model Check
Send Tomarok the full model code, nameplate photo and application details. The team can compare the existing configuration with the current Yokogawa product structure, identify missing information and determine what needs to be verified before a replacement or new order code is proposed. For differential-pressure applications, Tomarok can also connect the enquiry to the relevant differential pressure transmitters and supporting technical content.
