Triconex Tricon 3805H Analog Output Module

Technical Dossier

Product Details And Specifications

Triconex Tricon Series: Comprehensive Module Range and Technical Overview

The Triconex Tricon platform is one of the most widely deployed Safety Instrumented System (SIS) architectures in global heavy industry. Installed across petrochemical complexes, nuclear power stations, offshore platforms, LNG terminals, and refinery process units, the Tricon system operates on a Triple Modular Redundancy (TMR) architecture — three independent processing paths with continuous cross-comparison — delivering IEC 61511 / IEC 61508 SIL 3-rated protection. The 3805H is a high-density Analog Output module within this platform, providing 8 channels of 4–20 mA output for final control element interfaces including control valves, positioners, and variable speed drives in safety-critical loops.

The Tricon system has been the backbone of Emergency Shutdown (ESD), High Integrity Pressure Protection (HIPPS), Burner Management (BMS), and Fire & Gas (F&G) systems for over three decades. Its installed base spans Schneider Electric (post-acquisition of Invensys/Triconex), Shell, ExxonMobil, Saudi Aramco, BASF, and hundreds of tier-1 operators globally.

The Evolution of Tricon Architecture

The Tricon platform originated in the late 1980s under Triconex Corporation, later acquired by Invensys and subsequently by Schneider Electric. The architecture has evolved through several generations while maintaining backward compatibility at the chassis and backplane level — a critical design decision that has extended the operational life of early installations into the 2020s.

Generation 1 (Tricon v1–v7, 1988–1998): Original TMR architecture with dedicated I/O modules and MP3008 main processors. Chassis-based design with passive backplane. Limited to serial communications (Triconex Application Protocol, TAP).

Generation 2 (Tricon v9–v10, 1999–2010): Introduction of the Enhanced Intelligent Communication Module (EICM) and Hiway Interface Module (HIM). Expanded I/O density. Support for Modbus TCP and OPC DA. The 3805H belongs to this generation's I/O module family, compatible with both v9 and v10 main processors.

Generation 3 (Tricon CX, 2010–present): Compact chassis form factor, integrated Ethernet-based safety network (TriStation 1131 v4+), and enhanced cybersecurity hardening per IEC 62443. Many legacy I/O modules including the 3805H retain physical and electrical compatibility with Tricon CX chassis via adapter backplanes, enabling brownfield migration without full I/O replacement.

Compatibility note: The 3805H operates on the standard Tricon I/O bus and is compatible with chassis models 8310, 8311, 8312 (main chassis) and 8320, 8321 (expansion chassis). It is not compatible with Trident or Tri-GP platforms.

Tricon Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly stocked modules within the Triconex Tricon platform. Each entry reflects a distinct functional role within the TMR architecture.

Analog Output Modules:

• 3805H: 8-channel, 4–20 mA analog output, high-density, SIL 3 rated, TMR-compatible.
• 3805E: 8-channel analog output, earlier revision, functionally equivalent to 3805H with revised diagnostics firmware.
• 3703E: 8-channel, 4–20 mA analog input module, TMR, with HART pass-through support.
• 3704E: 16-channel analog input, 4–20 mA, high-density I/O for process variable acquisition.

Digital Output Modules:

• 3805H: (see above — dual-listed in some catalogs as DO-capable in voltage output configuration).
• 3601E: 32-channel digital output, 24 VDC, solid-state, TMR.
• 3602E: 16-channel digital output, 115 VAC, relay-isolated, for solenoid valve interfaces.
• 3603E: 16-channel digital output, 24 VDC, high-current, for motor starter interfaces.

Digital Input Modules:

• 3501E: 32-channel digital input, 24 VDC, TMR, standard field wiring.
• 3502E: 32-channel digital input, 48 VDC, for legacy field instrument interfaces.
• 3503E: 16-channel digital input, 115 VAC, for high-voltage field devices.
• 3504E: 32-channel digital input, 24 VDC, with enhanced noise immunity for offshore environments.

Processor & Communication Modules:

• 3008: Main Processor (MP) module, TMR, 32-bit, TriStation 1131 compatible.
• 3006: Main Processor, earlier generation, 16-bit architecture, limited to TriStation v3.
• 3007: Main Processor, intermediate revision, supports v9 chassis.
• 4351B: Enhanced Intelligent Communication Module (EICM), Modbus RTU/TCP, OPC.
• 4119A: Hiway Interface Module (HIM), for DCS integration via Foxboro I/A or Honeywell TDC 3000 hiway.
• 4100: Network Communication Module (NCM), Ethernet-based, TriStation 1131 v4 compatible.

Power Supply Modules:

• 8110: AC Power Distribution Panel, 120/240 VAC input, for main chassis.
• 8112: DC Power Supply, 24 VDC output, redundant pair configuration.

Sourcing Hard-to-Find & Obsolete Tricon Parts

Schneider Electric has progressively transitioned its safety system portfolio toward the Tricon CX and EcoStruxure Safety Expert platforms. As a result, a significant portion of the legacy Tricon I/O module catalog — including the 3805H, 3805E, 3601E, 3501E, and 3006/3007 processor modules — has been classified as End-of-Life (EOL) or Last-Time-Buy (LTB) by the OEM.

DriveKNMS maintains a dedicated inventory of tested, refurbished, and new-surplus Tricon modules to support operators who require lifecycle extension beyond OEM support windows. Our sourcing network covers:

• Direct surplus acquisition from decommissioned plant shutdowns and system upgrades.
• Certified refurbishment with full functional test against Triconex module test specifications.
• Cross-reference matching for superseded part numbers (e.g., 3805E → 3805H upgrade path).
• Emergency same-day dispatch for unplanned outage scenarios.

For plants operating under long-term service agreements (LTSA) or with capital expenditure constraints that prevent full system migration, DriveKNMS provides a structured spare parts management program covering the full Tricon I/O catalog.

Quality Control for the Tricon Range

Tricon modules incorporate a TMR internal bus architecture where each of the three processing legs communicates via a dedicated backplane segment. Standard bench testing is insufficient to validate TMR integrity — DriveKNMS applies a protocol-specific test procedure for each module type:

• Analog Output (3805H/3805E): 8-channel loop calibration at 4 mA, 12 mA, and 20 mA setpoints. Output accuracy verified to ±0.1% full scale. TMR voter logic exercised via simulated leg-fault injection. HART communication integrity check on all channels.
• Digital I/O modules: State transition testing across all 32 channels. Isolation resistance measurement between channel groups (>100 MΩ). Inrush current profiling for relay output variants.
• Processor modules (3006/3007/3008): Full TriStation 1131 download and compile cycle. Memory diagnostic pass. TMR synchronization verification across all three legs under loaded conditions.
• Communication modules (4351B/4119A/4100): Modbus register map validation. Ethernet port link integrity and packet loss test. OPC DA tag enumeration verification.

All modules are tested in a Tricon chassis environment (not standalone), ensuring backplane bus compatibility is confirmed prior to dispatch. Test records are retained and available upon request.