PLCs, Power Supplies & Others

Technical Overview

The EJA120A measures low differential pressure with exceptional sensitivity using resonant silicon sensor technology. This transmitter delivers accurate readings for flow, level, and filter monitoring applications. Process engineers choose this instrument for its superior low-range performance and long-term reliability. The EJA120A incorporates digital compensation to minimize environmental effects on measurement accuracy.

Key Specifications

Low-Range Measurement Performance

The EJA120A specializes in low differential pressure measurement from 0.025 to 10 kPa. This transmitter achieves an accuracy of ±0.15% of span across its calibrated measurement range. The resonant silicon sensor provides direct digital output without intermediate analog conversion. Long-term stability remains within ±0.1% per year, ensuring consistent performance over extended periods. The device offers a response time of 150 ms with damping applied for smooth readings.

Pressure Handling and Overload Protection

This differential pressure transmitter withstands a static pressure limit of 16 MPa without damage. The EJA120A handles overpressure events effectively due to its robust sensor construction. Such high overload capability ensures reliable operation during process upsets and startups. The transmitter maintains measurement integrity even when subjected to frequent pressure fluctuations.

Output Signal and Communication Capabilities

The EJA120A provides a standard 4–20 mA analog output with HART digital communication protocol. This loop-powered transmitter operates from a 17 to 42 V DC supply voltage. At 24 V DC, the device supports a load resistance of up to 600 Ω. Operators can configure parameters and perform diagnostics via the HART interface. The transmitter also supports remote zero and span adjustments for convenient field calibration.

Process Connections and Wetted Components

Standard process connections feature 1/4 NPT female threads for low-pressure applications. The EJA120A also offers Rc 1/4 connections as an alternative option. Wetted parts utilize 316L stainless steel with a Hastelloy C-276 diaphragm. This material combination provides excellent corrosion resistance for various process fluids. The transmitter uses silicone oil as the standard fill fluid for reliable pressure transmission.

Environmental Tolerance and Enclosure Design

The EJA120A operates reliably across process temperatures from -40°C to 85°C. Ambient temperature variations produce only ±0.06% effect per 10°C on measurement accuracy. The aluminum housing carries an IP67 and NEMA 4X rating for ingress protection. This rugged enclosure suits outdoor installations and harsh industrial environments. Storage temperatures from -50°C to 90°C do not affect instrument integrity.

Physical Dimensions and Weight

The transmitter housing measures 190 mm in height, 108 mm in width, and 135 mm in depth. The EJA120A weighs 3.6 kg without the optional mounting bracket assembly. The electrical connection accommodates 1/2 NPT or M20 × 1.5 cable glands. Installers can mount the transmitter directly onto pipe stands or wall brackets. The compact design saves valuable space in crowded instrument panels.

Application Areas

The EJA120A suits low-flow measurement using orifice plates and pitot tubes. This transmitter also performs filter monitoring by detecting pressure drops across filter elements. Level measurement in open tanks benefits from the unit’s low-range sensitivity. The transmitter handles clean liquids, gases, and air in HVAC applications. Its high sensitivity makes it ideal for cleanroom differential pressure monitoring.

Installation and Operational Guidance

Mount the EJA120A vertically with impulse piping sloping downward from the process taps. Connect the high and low pressure ports using appropriate fittings and tubing. Wire the two-wire loop to the terminal block with correct polarity. Configure zero and span values using the HART communicator or software. Perform periodic zero checks to ensure measurement accuracy over time. The transmitter requires minimal maintenance due to its digital sensor design.

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