Yokogawa A2EE2A-T S1 Digital Input Module

Technical Dossier

Product Details And Specifications

Yokogawa A2EE Series Technical Notes

The Yokogawa A2EE series Digital Input (DI) modules are field-proven I/O components deployed across the CENTUM CS 3000 and CENTUM VP distributed control systems. These modules occupy a critical position in global heavy industry installations — including petrochemical complexes, LNG terminals, nuclear power auxiliary systems, crude oil refineries, and continuous-process chemical plants. The A2EE series provides the discrete signal acquisition layer that connects field instruments, valve position switches, motor status contacts, and safety interlock circuits to the CENTUM controller backbone. Their 32-channel density, galvanic isolation architecture, and compatibility with the FCS (Field Control Station) bus make them a standard specification item in engineering procurement packages worldwide.

The Evolution of A2EE Series Architecture

The A2EE module lineage traces to Yokogawa's CENTUM CS platform introduced in the mid-1990s, which established the modular I/O card format still used in CENTUM VP today. Early A2EE variants operated under the CS 3000 R3.x firmware environment with a parallel backplane bus. The transition to CENTUM VP (introduced circa 2008) brought enhanced diagnostics, online replacement capability (hot-swap), and expanded HART pass-through on analog variants. The A2EE2A-T S1 specifically targets 24 VDC dry-contact and wet-contact digital inputs, with the "-T" suffix denoting terminal board compatibility and "S1" indicating the first-generation slot assignment standard.

A2EE Series Full Catalog & Functionalities (SKU List)

The following SKUs represent the verified A2EE and closely related CENTUM CS 3000 / VP I/O module range. Each entry reflects a distinct functional role within the FCS I/O nest:

Digital Input (DI) Modules

• A2EE2A-T S1: 32-ch 24VDC DI module, dry/wet contact, terminal board type, slot-1 assignment
• A2EE2B-T S1: 32-ch 24VDC DI module, high-speed scan variant, terminal board type
• A2EE4A-T S1: 32-ch 48VDC DI module, extended voltage range, terminal board type
• A2EE6A-T S1: 32-ch 100/110VAC DI module, AC-input field signals, terminal board type
• A2EE8A-T S1: 32-ch 200/220VAC DI module, high-voltage AC discrete input

Digital Output (DO) Modules

• A2ED2A-T S1: 32-ch 24VDC DO module, transistor output, terminal board type
• A2ED4A-T S1: 16-ch relay DO module, 250VAC/30VDC contact output
• A2ED6A-T S1: 32-ch 24VDC DO module, high-current sink output variant

Analog Input (AI) Modules

• A2EL2A-T S1: 16-ch 4-20mA AI module, HART-enabled, terminal board type
• A2EL4A-T S1: 8-ch thermocouple/RTD AI module, multi-sensor type
• A2EL6A-T S1: 16-ch voltage input AI module, +/-10V / 0-5V range

Analog Output (AO) Modules

• A2EM2A-T S1: 8-ch 4-20mA AO module, HART-enabled, terminal board type
• A2EM4A-T S1: 8-ch voltage AO module, 0-10V output range

Communication & CPU Modules

• A2ER2A: FCS communication bus coupler module, V-net interface
• A2EP2A: FCS power supply module, 24VDC regulated, redundancy-capable
• A2EC2A: FCS CPU/controller module, CENTUM CS 3000 R3 compatible
• A2EF2A: Field bus interface module, Foundation Fieldbus H1 segment coupler

Sourcing Hard-to-Find & Obsolete A2EE Series Parts

DriveKNMS supports installed-base sourcing for this series through RFQ review, including model matching, condition checks and documentation requirements before quotation.

Quality Control for the A2EE Series Range

The A2EE2A-T S1 and related modules incorporate a multi-layer backplane connector and a dedicated I/O bus interface that requires targeted test procedures beyond standard power-on checks. DriveKNMS applies the following verification protocol to all A2EE series units: