YOKOGAWA AAI135 Modules

Technical Dossier

Product Details And Specifications

YOKOGAWA AAI135 Series: Comprehensive Module Range and Technical Overview

The YOKOGAWA AAI135 series is a family of analog input modules deployed within the CENTUM VP and CENTUM CS 3000 Distributed Control Systems (DCS). These modules occupy a critical position in global heavy industry installations, including petrochemical complexes, oil refineries, nuclear power facilities, and large-scale chemical processing plants. The AAI135 platform supports multi-channel 4–20 mA analog signal acquisition with HART communication capability, enabling field device diagnostics without process interruption. Its modular architecture integrates directly into the Field Control Station (FCS) backplane, conforming to YOKOGAWA's standard I/O bus protocol. Installed base spans facilities across Asia-Pacific, the Middle East, Europe, and the Americas, making long-term parts availability a critical operational requirement for plant maintenance teams.

The Evolution of AAI135 Architecture

The AAI135 module was introduced as part of YOKOGAWA's CENTUM CS 3000 platform in the late 1990s, designed to replace earlier discrete analog input cards with a unified, bus-compatible module format. The original AAI135-S00 variant established the baseline 16-channel single-ended analog input specification. Subsequent suffix revisions (S1, S2, S3) introduced incremental changes to firmware revision levels, conformal coating specifications, and EMC compliance ratings to meet evolving IEC and ATEX standards.

With the transition to CENTUM VP (introduced circa 2008), YOKOGAWA maintained backward hardware compatibility for the AAI135 form factor, allowing existing CS 3000 installations to migrate to VP supervisory software without replacing field I/O hardware. This cross-generation compatibility is a defining characteristic of the AAI135 family and a primary reason for its continued presence in brownfield plant environments. As of 2026, the AAI135 series is in the mature-to-end-of-life phase of its product lifecycle. YOKOGAWA has transitioned new project specifications toward the CENTUM VP R6 platform with next-generation I/O modules (e.g., AAI143, AAI141). However, the installed base of AAI135 modules remains substantial, and DriveKNMS maintains dedicated stock and sourcing channels for all suffix variants to support long-term maintenance contracts and emergency replacement requirements.

AAI135 Full Catalog & Functionalities (SKU List)

The following SKUs represent the documented AAI135 series range. Each entry is classified by functional role within the CENTUM DCS architecture:

Analog Input Modules (AI)

• AAI135-S00: 16-ch analog input, 4–20 mA, non-HART, standard coating
• AAI135-S00 S2: 16-ch analog input, 4–20 mA, non-HART, revision S2 firmware/coating spec
• AAI135-S00 S3: 16-ch analog input, 4–20 mA, non-HART, revision S3 EMC-enhanced variant
• AAI135-H00: 16-ch analog input, 4–20 mA, HART-enabled, standard coating
• AAI135-H00 S2: 16-ch analog input, HART-enabled, revision S2 specification
• AAI135-H00 S3: 16-ch analog input, HART-enabled, revision S3 EMC-enhanced
• AAI135-H50: 16-ch analog input, HART, intrinsically safe barrier integrated variant
• AAI135-H50 S2: IS-barrier integrated, HART, revision S2 conformal coat
• AAI135-S50: 16-ch analog input, non-HART, intrinsically safe barrier integrated
• AAI135-S50 S2: IS-barrier integrated, non-HART, revision S2 specification

Associated Bus Interface & Termination Units

• ANT1D-S00: Node interface unit for AAI135 I/O bus segment, standard rail mount
• ANT1D-S00 S2: Node interface unit, revision S2, enhanced surge protection
• AIP835-S00: I/O power supply module for AAI135 FCS node, 24 VDC output
• AIP835-S00 S2: I/O power supply, revision S2, extended temperature range
• ATD5D-S00: Terminal board for AAI135 field wiring termination, 16-channel
• ATD5D-H00: Terminal board, HART pass-through variant, 16-channel
• ACM12-S00: Communication module for CENTUM FCS, supports AAI135 node segment

Sourcing Hard-to-Find & Obsolete AAI135 Parts

As the AAI135 series enters end-of-life status within YOKOGAWA's active product portfolio, OEM factory orders for new units are no longer reliably fulfilled. DriveKNMS operates a dedicated procurement channel for discontinued and hard-to-source CENTUM I/O modules. Our inventory strategy for the AAI135 range includes:

• Direct stock of pulled and refurbished AAI135 modules from decommissioned plant assets, fully tested to original specification.
• Cross-referencing of suffix variants (S00, S2, S3, H00, H50) to identify functional equivalents where direct replacements are unavailable.
• Global sourcing network covering surplus equipment dealers in Japan, Germany, the United States, and Southeast Asia.
• Emergency same-day quotation service for unplanned plant shutdowns requiring immediate AAI135 replacement.
• Long-term maintenance agreements (LTMAs) providing reserved stock allocation for facilities with large AAI135 installed bases.

Quality Control for the AAI135 Range

The AAI135 module's multi-channel analog input architecture and backplane bus interface require a structured test protocol that differs from standard relay or digital I/O modules. DriveKNMS applies the following procedures to all AAI135 units prior to shipment:

• Backplane Bus Communication Test: Each module is seated in a live CENTUM CS 3000 or CENTUM VP test rack. The FCS is polled to confirm the module registers correctly on the I/O bus with the correct module type identifier and channel count.
• 16-Channel Signal Injection: A calibrated 4–20 mA signal source is applied sequentially to all 16 input channels. Measured values are compared against a ±0.1% full-scale accuracy threshold.
• HART Communication Verification (H-suffix variants): HART master polling is executed on all channels to confirm HART layer 7 communication integrity and device descriptor response.
• Conformal Coating Inspection: UV lamp inspection confirms coating coverage on all PCB surfaces, with particular attention to the analog front-end circuitry and bus connector pins.
• Thermal Cycling: Units are subjected to a 0°C to 55°C thermal cycle to screen for latent solder joint failures common in aged industrial electronics.
• Final Documentation: Each unit ships with a test report recording channel-by-channel accuracy results, bus communication confirmation, and inspector sign-off.

For AAI135 sourcing inquiries, technical cross-reference support, or emergency replacement requests:

• Email: sale@driveknms.com
• WhatsApp: +86 18359293191
• Web: driveknms.com

© 2026 DriveKNMS. All trademarks belong to their respective owners. Specifications are for reference only and subject to change without notice. Verify all parameters against official documentation before installation.