ICS Triplex T3401 Trusted Series Modules

Technical Dossier

Product Details And Specifications

ICS Triplex Trusted Series: Comprehensive Module Range and Technical Overview

The ICS Triplex Trusted series is a Triple Modular Redundant (TMR) safety system platform deployed across the most demanding continuous-process industries globally. Installed in petrochemical complexes, offshore platforms, nuclear power stations, LNG terminals, and pipeline SCADA networks, the Trusted architecture provides IEC 61508 SIL 3-certified fault tolerance through hardware redundancy at the module, backplane, and communication bus levels. The platform's deterministic scan cycle and hot-swap capability make it the reference standard for Emergency Shutdown Systems (ESD) and High Integrity Pressure Protection Systems (HIPPS) where unplanned downtime carries direct operational and safety consequences. The T3401 — a 24 VDC, 32-channel Digital Input module — is one of the most widely deployed field interface modules in the Trusted installed base, found in ESD cabinets across refineries, chemical plants, and offshore topsides on every major producing continent.

The Evolution of Trusted Series Architecture

ICS Triplex introduced the Trusted platform in the early 1990s as a successor to its earlier TMR designs, targeting SIL 3 applications that required certified hardware redundancy without reliance on software voting alone. The original T8000-series chassis established the backplane architecture: three independent processing lanes (A, B, C) with continuous cross-comparison and automatic fault isolation. Each I/O module communicates over a triplicated internal bus, ensuring that a single-point hardware failure in any lane does not propagate to the process output.

The T3000-series field I/O modules — including the T3401 Digital Input and T3480 Digital Output — were introduced as the primary field interface layer for this architecture. These modules mount directly onto T8110 baseplates and communicate with the TMR processor via the triplicated backplane bus. The design philosophy prioritized deterministic fault detection: each channel is independently monitored across all three lanes, with disagreement triggering automatic lane isolation rather than a system trip.

In the mid-2000s, Rockwell Automation acquired ICS Triplex, integrating the Trusted platform into its safety portfolio alongside GuardLogix. This transition introduced firmware updates and new communication modules (Profibus DP, Modbus TCP, EtherNet/IP) while maintaining backward compatibility with existing T8000 and T3000 chassis hardware. Plants commissioned in the 1990s can therefore integrate modern network adapters without replacing the core I/O infrastructure. As of 2026, the Trusted platform is in its mature/end-of-active-production phase. Rockwell no longer manufactures new Trusted modules as standard catalog items. Third-party spare parts sourcing — including tested surplus and refurbished stock — is the primary lifecycle strategy for the global Trusted installed base.

Trusted Series Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, real-world part numbers from the ICS Triplex Trusted platform installed base. Modules are classified by functional category.

Digital Input (DI) Modules

• T3401: 24 VDC DI, 32-channel, TMR-voted, field-wiring via T8110 baseplate, SIL 3.
• T3411: 120 VAC DI, 16-channel, optically isolated, for high-voltage field devices.
• T3420: 24 VDC DI with enhanced per-channel diagnostics, SIL 3 rated.
• T3422: 24 VDC DI, 32-channel, NAMUR sensor compatible, intrinsically safe interface.

Digital Output (DO) Modules

• T3480: 24 VDC DO, 16-channel, solid-state relay output, TMR voted.
• T3481: 120 VAC DO, 8-channel, for solenoid valve and actuator drive applications.
• T3484: 24 VDC DO, 8-channel, high-current output, for large solenoid loads.

Analog Input (AI) Modules

• T8403: AI, 8-channel, 4–20 mA, 12-bit resolution, HART-transparent.
• T8431: AI, 16-channel, ±10 V / 4–20 mA configurable, high-density I/O.
• T8461: TC/RTD Input, 8-channel, supports J/K/T/E thermocouple and PT100 RTD.
• T8462: RTD Input, 16-channel, PT100/PT1000, for temperature-critical process loops.

Analog Output (AO) Modules

• T8480: AO, 8-channel, 4–20 mA, 12-bit, for control valve positioner drive.
• T8482: AO, 4-channel, 4–20 mA, high-accuracy, for precision flow control applications.

CPU / Controller Modules

• T8110: Trusted Controller baseplate; primary chassis interface for I/O module mounting and backplane bus.
• T8151B: Trusted Processor module; TMR CPU, 32 MB RAM, executes IEC 61131-3 safety logic.
• T8110B: Redundant Power Supply module; 24 VDC input, triplicated internal rails, hot-swap capable.

Communication & Network Modules

• T8800: Trusted Communication Interface; Ethernet TCP/IP gateway for DCS historian and HMI integration.
• T9432: Profibus DP Communication module; master/slave configurable, for field device integration.
• T9451: Modbus RTU/TCP Communication module; serial and Ethernet dual-port, legacy DCS interfacing.
• T9802: EtherNet/IP Adapter module; CIP-compliant, for integration with Rockwell ControlLogix supervisory systems.

Power Supply Modules

• T8120: AC/DC Power Supply; 120/240 VAC input, 24 VDC output, for chassis power distribution.
• T8121: DC/DC Power Supply; 48 VDC input, 24 VDC output, for telecom-standard power environments.

Sourcing Hard-to-Find & Obsolete Trusted Series Parts

With Rockwell Automation having transitioned the Trusted platform to end-of-active-production status, OEM new-stock availability for modules such as the T3401, T8151B, T9432, and T8403 is no longer guaranteed through standard distribution channels. Plants operating Trusted-based ESD and HIPPS systems face a sourcing gap that cannot be resolved through standard Rockwell distributors or authorized integrators.

DriveKNMS specializes in lifecycle extension support for the Trusted platform. Our inventory strategy covers: (1) tested surplus stock sourced from decommissioned plant assets with full traceability; (2) factory-refurbished modules with complete functional test documentation; (3) cross-reference matching for superseded part numbers to current equivalents where applicable. All modules are tested against original ICS Triplex functional specifications prior to dispatch. Traceability documentation — including test records, serial number logs, and inspection certificates — is provided on request for regulated industries including nuclear, offshore, and downstream petrochemical.

Quality Control for the Trusted Series Range

The Trusted platform's TMR architecture introduces specific test requirements that differ from standard PLC module verification. Each module contains three independent processing lanes whose cross-comparison logic must be validated under both normal and fault-injected conditions. DriveKNMS applies the following test protocol to all Trusted series modules prior to dispatch:

• Backplane bus continuity verification across all three lanes using dedicated Trusted chassis test fixtures.
• Channel-by-channel signal injection and readback for all DI, DO, AI, and AO modules at rated voltage and current.
• Fault injection test: deliberate single-lane failure simulation to confirm TMR voting logic and automatic fault isolation behavior.
• Communication module validation: protocol handshake verification (Profibus DP, Modbus RTU/TCP, EtherNet/IP) using dedicated protocol analyzers.
• 48-hour burn-in cycle under powered operation at ambient temperature prior to final inspection and packaging.
• Serial number recording and test record retention; documentation available to customers upon request.

© 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.