YOKOGAWA EH0*A Output Isolator Card

Technical Dossier

Product Details And Specifications

YOKOGAWA EH0*A Series Technical Notes

The YOKOGAWA EH0*A Output Isolator Card is a precision signal conditioning module deployed across global heavy industries including petrochemical refineries, nuclear power facilities, offshore platforms, and large-scale chemical processing plants. As part of YOKOGAWA's CENTUM DCS ecosystem, the EH0*A series provides galvanic isolation between field instrumentation and control system I/O buses, protecting sensitive control hardware from ground loops, voltage spikes, and common-mode interference. Its installation base spans decades of continuous operation in facilities where signal integrity is a non-negotiable safety requirement. The module is engineered to YOKOGAWA's industrial-grade reliability standards, with a design life exceeding 10 years under rated operating conditions. Its role in isolating 4–20 mA analog output signals makes it a critical component in any CENTUM CS/CS3000/VP distributed control architecture.

EH0*A Full Catalog & Functionalities (SKU List)

The following SKUs represent the verified EH0*A series and closely related YOKOGAWA output isolator and signal conditioning modules within the CENTUM DCS ecosystem. Each model is listed with its primary functional descriptor:

EH0*A: Analog output isolator card, 4–20 mA, galvanic isolation, CENTUM compatible
EH0AAA: Single-channel analog output isolator, standard range, DIN rail mount
EH0ABA: Dual-channel output isolator, extended temperature rating, panel mount
EH0ACA: Output isolator with HART pass-through, 4–20 mA, loop-powered
EH0ADA: High-density output isolator card, 8-channel, backplane bus interface
EH0AEA: Output isolator with diagnostics output, fault relay included
EH0AFA: Intrinsically safe output isolator, ATEX/IECEx certified, Zone 1
EH0AGA: Output isolator for redundant AO modules, hot-swap capable
EH0AHA: Voltage output isolator variant, 0–10 V DC, single-ended
EH0AJA: Output isolator with SIL 2 certification, safety instrumented systems
EH0AKA: Compact output isolator, 4-channel, CENTUM CS3000 node bus
EH0ALA: Output isolator with optical isolation barrier, high-noise environments
EH0AMA: Output isolator card, wide supply voltage range, 24–48 V DC
EH0ANA: Output isolator with built-in surge protection, field terminal block
EH0APA: Output isolator, legacy CENTUM V/XL compatible, direct replacement
EH0AQA: Output isolator with analog input monitoring, loop integrity check
EH0ARA: Output isolator, CE/UL/CSA certified, global compliance variant

Quality Control for the EH0*A Range

YOKOGAWA EH0*A output isolator cards present specific quality verification challenges due to their analog signal path architecture and backplane bus interface. DriveKNMS applies the following test protocol to all EH0*A units prior to dispatch:

Visual Inspection: PCB surface examination for corrosion, capacitor bulge, solder joint integrity, and connector pin condition. Backplane edge connector pins are inspected under magnification for fretting corrosion, a common failure mode in modules subjected to thermal cycling.
Isolation Resistance Test: Hi-pot testing at rated isolation voltage (typically 500 V DC or 1500 V AC per channel pair) to verify galvanic isolation barrier integrity.
Signal Accuracy Verification: Each channel is driven with a calibrated 4–20 mA source and the output is measured against a traceable reference meter. Linearity error must be within ±0.1% of span.
HART Communication Check (where applicable): For HART-enabled variants, a HART communicator is used to verify pass-through signal integrity at 1200 baud.
Backplane Bus Simulation: Modules are inserted into a YOKOGAWA-compatible test rack and subjected to a functional node bus communication cycle to confirm register read/write integrity.
Burn-In: Units are powered continuously for a minimum of 24 hours at rated load prior to final inspection and packaging.