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Yokogawa EJA430E-JBS4815
Product Series: EJA430E — DPharp Digital Pressure Transmitter
Product Introduction:
The EJA430E-JBS4815 is a high-performance absolute pressure transmitter using Yokogawa’s DPharp (Digital Phase Measurement) single-crystal silicon resonant sensor technology. The “JBS” indicates a low-range absolute pressure model, and “4815” defines the specific output, process connection, and material configuration. It provides superior accuracy, stability, and fast response for absolute pressure measurement.
Detailed content
Working Principle:
The DPharp sensor consists of a single-crystal silicon diaphragm with two H-shaped resonant beams diffused on its surface. Pressure applied to the diaphragm creates stress in the resonant beams, changing their resonant frequency. The frequency difference between the two beams is measured and converted to a digital pressure value. This differential measurement cancels out temperature effects, providing exceptional accuracy and long-term stability.
Technical Specifications:
| Parameter | Value |
|---|---|
| Measurement Type | Absolute Pressure |
| Pressure Range | 0 to 100 kPa (JBS model — low range absolute) |
| Accuracy | ±0.04% of URL (Upper Range Limit) |
| Output Signal | 4-20 mA DC + HART 7 (2-wire), or 4-20 mA + HART (4-wire) |
| Overpressure Rating | 3× URL (up to 300 kPa) |
| Process Temperature | -40°C to +120°C (standard silicon sensor) |
| Ambient Temperature | -40°C to +85°C |
| Process Connection | G1/2″ female thread (per 4815 configuration) |
| Wetted Material | SUS316L stainless steel (diaphragm and process connection) |
| Power Supply | 12-45 V DC (2-wire) or 100-240 V AC (4-wire) |
| Protection Rating | IP67 (NEMA 4X) |
| Ex Rating | Ex ia IIC T6 Ga / Ex d IIC T6 Gb |
| SIL Rating | SIL 2 / SIL 3 (per IEC 61508) |
| Response Time | ≤ 5 ms (digital damping off) |
| Long-term Stability | ±0.04% URL per 10 years |
| Communication | HART 7, FOUNDATION Fieldbus H1, PROFIBUS PA (optional) |
Material Composition:
- Sensor diaphragm: Single-crystal silicon (SSS — Stress Sensitive Single crystal Silicon)
- Housing: SUS316L stainless steel
- O-rings: Viton (standard), Kalrez (high-temp/chemical)
- Terminal housing: Polybutylene terephthalate (PBT), glass-filled
Advantages:
- World-class accuracy of ±0.04% URL
- DPharp technology provides 10× better long-term stability than conventional capacitive sensors
- Fast 5 ms response time for dynamic pressure monitoring
- SIL 2/SIL 3 certified for safety instrumented functions
- Absolute pressure measurement — no need for atmospheric reference
- Low static pressure effect — accuracy maintained across the full range
Applicable Industries:
Atmospheric pressure monitoring, cleanroom pressure control, HVAC differential pressure, barometric compensation, laboratory pressure standards, semiconductor manufacturing, pharmaceutical cleanrooms
Installation Requirements:
- Mount with process connection pointing upward for gas/vapor service
- For liquid service, mount with process connection pointing downward or sideways
- Use a pressure tap with smooth internal bore — avoid sharp edges
- Connect impulse tubing with slope away from the transmitter to prevent liquid accumulation
- Ensure no condensation forms in the impulse line for gas service
Usage Notes:
- Absolute pressure sensors are sensitive to barometric changes — account for this in control strategy
- Perform zero calibration at the actual installation elevation
- The JBS low-range model is designed for near-atmospheric pressures — do not apply overpressure beyond 3× URL
- Use HART communicator to verify sensor diagnostics and configure damping
- Periodically check the zero point — DPharp sensors have minimal drift but verification is recommended annually
