Yokogawa EJA438 Gauge Pressure Transmitter with Remote Diaphragm Seal
EJA438W and EJA438N Diaphragm Sealed Gauge Pressure Transmitters
Product Description
Yokogawa EJA438W and EJA438N Diaphragm Sealed Gauge Pressure Transmitters
Diaphragm seal is used to prevent process medium from entering directly into the pressure-sensing assembly of the pressure transmitter. It is connected to the transmitter using capillary filled with fill fluid.
Models EJA438W and EJA438N Diaphragm Sealed Gauge Pressure Transmitters can be used to measure liquid, gas or steam pressure. They output a 4 to 20 mA DC signal corresponding to the measured
pressure.
The models EJA438W and EJA438N feature remote setup and monitoring through communications with the model BT200/100 BRAIN TERMINAL, CENTUM CS/ XL system etc.
Models EJA438W and EJA438N Diaphragm Sealed Gauge Pressure Transmitters can be used to measure liquid, gas or steam pressure. They output a 4 to 20 mA DC signal corresponding to the measured
pressure.
The models EJA438W and EJA438N feature remote setup and monitoring through communications with the model BT200/100 BRAIN TERMINAL, CENTUM CS/ XL system etc.
Features
The EJA-A series is Yokogawa's most successful pressure transmitter line. First released in 1991, it continues to offer high performance and high reliability for any application. With an installed base of over 4-1/2 million EJA-A transmitters worldwide, it has a proven track record that makes it a true industry workhorse.
The EJA438 is a Gauge Pressure Transmitter with a Remote Diaphragm seal attached.
It is available with a Flush Type Remote Seal (EJA438W) or an Extended Type Remote Seal (EJA438N).
EJA438 features include:
0.2% Accuracy
700 ms Response Time
External Zero Adjust
700 ms Response Time
External Zero Adjust
Benefits
High - precision Measurement: It adopts a monocrystalline silicon resonant sensor, with an accuracy as high as ±0.075%, which can provide more accurate pressure measurement results, meeting the needs of high - precision measurement in various industrial scenarios.
Excellent Over - pressure Resistance: It has excellent over - pressure characteristics. After 100,000 consecutive one - way over - pressure tests, the influence is ≤±0.03%, which can ensure the stability of the measurement performance under harsh conditions and is not easily affected by abnormal pressure.
Good Stability: Monocrystalline silicon has no hysteresis phenomenon for pressure or temperature changes. The EJA438W uses this material sensor to minimize the influence of over - pressure, temperature changes, and static pressure, thus providing excellent long - term stability and reducing the frequency of instrument calibration and maintenance
Specification
Item | valve |
Type | Diaphragm-sealed gauge/absolute pressure transmitter (with "W" suffix for wet leg applications) |
Measuring Principle | Monocrystalline silicon resonant sensor technology |
Measurable Media | Liquids, gases, vapors, corrosive/high-viscosity/crystallizable media (isolated by diaphragm seal) |
Accuracy | ±0.075% of span (gauge type), ±0.1% of span (absolute type) |
Stability | ±0.2% URL/10 years |
Pressure Range | - Gauge pressure: -0.1 to 3 MPa, 0.46 to 14 MPa (varies by model) - Absolute pressure: 0 to 20 MPa (specific ranges depend on diaphragm material) |
Overpressure Resistance | Withstands 100,000 cycles of one-way overpressure with ≤±0.03% impact on accuracy |
Response Time | 90 ms (standard), adjustable up to 1600 ms |
Output Signal | - 4–20 mA DC with HART 5/7, BRAIN protocol - FF fieldbus - PROFIBUS PA |
Power Supply | - 10.5–42 V DC (HART: 16.4–42 V DC) - FF fieldbus: 9–32 V DC - PROFIBUS PA: 9–32 V DC |
Communication Protocols | HART 5/7, BRAIN, FOUNDATION fieldbus, PROFIBUS PA |
Temperature Range | - Operating: -40°C to +120°C - Storage: -40°C to +150°C |
Temperature Effect | ±0.2% of span/55°C (compensated within -20°C to +85°C) |
Protection Level | IP66/IP67, NEMA 4X |
Explosion Protection | Ex d (flameproof), Ex ia (intrinsic safety), Ex nA (non-incendive), certified for ATEX, FM, CSA, IECEx, etc. |
Process Connections | - Flange types: ANSI, JIS, DIN, GB (with diaphragm seal) - Wet leg design (for "W" type): Liquid-filled impulse lines for media isolation |
Diaphragm Materials | 316L stainless steel, Hastelloy C-276, Monel, Tantalum (optional PTFE coating) |
Self-Diagnosis Functions | 40+ functions (CPU/hardware failure, configuration error, pressure/temperature over-limit alarms, real-time reverse check) |
Display | Optional built-in LCD (5-digit numeric + 6-digit unit, shows pressure values, alarm codes, bar charts; independent circuit from output signal) |
