Yokogawa ET5 Signal Conditioner Modules: ET5*B

Technical Dossier

Product Details And Specifications

Yokogawa ET5 Series Technical Notes

The Yokogawa ET5 series signal conditioners occupy a well-established position in global heavy industry instrumentation infrastructure. Deployed across chemical processing plants, petroleum refineries, nuclear power facilities, and pulp and paper mills, the ET5 range serves as the field-signal isolation and conversion backbone for distributed control systems (DCS) and SCADA architectures. These modules accept raw sensor inputs — thermocouples, RTDs, millivolt sources, and milliamp loops — and output standardized 4–20 mA or 1–5 V DC signals compatible with Yokogawa CENTUM, STARDOM, and third-party DCS platforms. The ET5 series is manufactured to JIS and IEC standards, with CE marking for European installations and compliance with NAMUR NE21 for EMC immunity in industrial environments. Their DIN-rail form factor and plug-in terminal design reduce installation time and simplify field replacement without loop interruption.

The Evolution of ET5 Architecture

The ET5 series was introduced as part of Yokogawa's modular signal conditioning platform, succeeding earlier discrete transmitter designs that required individual field calibration. The original ET5 architecture used analog isolation amplifiers with transformer-coupled barriers, providing galvanic isolation up to 1500 V AC between input, output, and power supply circuits. This three-port isolation design became a defining characteristic of the series and remains relevant for installations where ground loops and common-mode noise are persistent problems in long cable runs.

ET5 Full Catalog & Functionalities (SKU List)

The following SKUs represent the verified ET5 series module range, classified by input type and output function. Each model is a discrete, independently powered signal conditioner in DIN-rail housing.

Thermocouple (T/C) Input Models:

• ET5*B: T/C input signal conditioner, 4–20 mA output, three-port isolation, cold-junction compensation, supports J/K/T/E/R/S/B/N type thermocouples.
• ET5AB: T/C input, 4–20 mA output, standard accuracy class, DIN rail mount, screw terminal connection.
• ET5BB: T/C input, 4–20 mA output, enhanced EMC shielding variant for high-noise environments.
• ET5CB: T/C input, 1–5 V DC output, voltage output variant for direct interface with high-impedance DCS analog inputs.
• ET5DB: T/C input, dual-channel output, single housing, used where two independent loop outputs are required from one sensor.

RTD Input Models:

• ET5*C: RTD input signal conditioner, 4–20 mA output, supports Pt100 (JIS/IEC), Pt50, Cu50, three-wire and four-wire connection.
• ET5AC: RTD input, 4–20 mA output, standard range -200°C to +850°C, DIN rail, screw terminals.
• ET5BC: RTD input, 4–20 mA output, narrow-span high-resolution variant for precision temperature measurement.
• ET5CC: RTD input, 1–5 V DC output, voltage output for compatibility with legacy analog input cards.

Millivolt (mV) Input Models:

• ET5*D: mV input signal conditioner, 4–20 mA output, input range configurable from ±10 mV to ±1000 mV, three-port isolation.
• ET5AD: mV input, 4–20 mA output, standard span, used with strain gauge bridges and low-level sensor outputs.
• ET5BD: mV input, 4–20 mA output, high-CMR (common-mode rejection) variant for long cable installations.

Current (mA) Input / Repeater Models:

• ET5*E: 4–20 mA input loop repeater/isolator, 4–20 mA output, galvanic isolation for loop separation between field and control room.
• ET5AE: 4–20 mA input, 4–20 mA output, passive loop-powered isolator variant, no external power supply required.
• ET5BE: 4–20 mA input, dual 4–20 mA output, signal splitter function, distributes one field signal to two independent control system inputs.

Potentiometer / Resistance Input Models:

• ET5*F: Potentiometer or resistance input, 4–20 mA output, used with position sensors, valve positioners, and slidewire transmitters.

Quality Control for the ET5 Range

• Input accuracy verification: Simulated sensor inputs (T/C millivolt equivalent, RTD resistance decade box, calibrated mA source) applied across the full configured span. Output measured against calibration standard traceable to NIST/NPL.
• Isolation integrity test: Hi-pot test at 1500 V AC applied between input, output, and power supply terminals to verify galvanic isolation barrier integrity.
• Cold-junction compensation check (T/C models): Module subjected to controlled ambient temperature variation; output deviation from expected value recorded and compared against Yokogawa specification.
• Loop burden test: Output loaded to maximum specified burden resistance; output linearity and stability verified under load.
• Visual and mechanical inspection: Terminal block condition, housing integrity, label legibility, and connector seating verified.