Description:

The ICS TRIPLEX T8850​ (and its enhanced variant T8850C) is a high-density Field Termination Assembly (FTA) manufactured by ICS TRIPLEX, now part of Rockwell Automation, designed specifically for the Trusted® Triple Modular Redundant (TMR) safety and critical control system platform . It serves as the primary physical interface and wiring hub between the Trusted TMR I/O modules (such as digital/analog output modules) and the field devices (e.g., valves, actuators, indicators) . This module does not perform logic processing but provides the terminal connections, channel grouping, and facilitates maintenance operations like hot-swapping, significantly simplifying system wiring, testing, and maintenance in complex safety instrumented systems (SIS) and emergency shutdown (ESD) applications .

Application Scenarios:

In a large chemical processing plant, dozens of critical control valves and shutdown actuators are managed by a Trusted TMR safety system to prevent hazardous events. Each valve requires a control signal from a TMR output module. Directly wiring 40 individual field devices back to individual channels on multiple I/O modules would be chaotic, error-prone, and difficult to maintain.

The ICS TRIPLEX T8850​ FTA is installed in the field marshalling cabinet. Its 40 output channels are pre-wired to the field devices . In the control cabinet, a single cable from a Trusted TMR output module (like a T8451 digital output module) connects to the T8850’s SmartSlot connector . The T8850 then distributes this signal to the designated group of field devices. Its core value lies in organization and reliability: it neatly terminates field wiring, provides clear channel grouping (5 groups of 8 channels), and supports hot-swapping of the upstream I/O module without disturbing the field wiring . This design drastically reduces commissioning time, minimizes wiring errors, and allows for rapid module replacement during online maintenance, ensuring the safety system’s high availability.

Main Parameters

T8850 (Legacy)

T8850C (Enhanced)

Notes/Source

Product Model​

ICS TRIPLEX T8850​

ICS TRIPLEX T8850C​

Manufacturer​

ICS TRIPLEX (Rockwell Automation)

ICS TRIPLEX (Rockwell Automation)

Product Category​

Field Termination Assembly (FTA) / Interface Module

Field Termination Assembly (FTA) / Interface Module

Primary Function​

Interface between Trusted TMR I/O modules and field devices

Interface between Trusted TMR I/O modules and field devices

Number of Channels​

40 output channels (grouped as 5×8)

40 output channels (grouped as 5×8)

Channel Type​

Configurable for Analog or Digital Output signals

Configurable for Analog or Digital Output signals

Compatible Modules​

T8451. T8461. T8480

T8451. T8461. T8480

Connection​

2-wire industry-standard field device connection

2-wire industry-standard field device connection

Power Supply​

24 V DC

24 V DC

Operating Temperature​

0 °C to +60 °C (or -20°C to +70°C per some sources)

0 °C to +60 °C (or similar)

Protection (Environmental)​

Standard

Conformal-coated PCB (IPC-610-3C)​ for 5x salt-fog life

Terminal Type​

Screw clamp (12-28 AWG)

“C-coded” spring terminals​ (0.34–2.5 mm² / 22-14 AWG)

Over-Voltage Protection (OVP)​

Fixed (e.g., ~33V)

Configurable group-level OVP​ (28V, 32V, 36V via software)

Cold-start Surge Clamp​

No

Yes​ (<5 A inrush limit)

EMC Immunity​

Standard (e.g., 10 V/m radiated)

Enhanced (IEC 61326-3-2:2021)​ – 30 V/m radiated, 2 kV surge on signal lines

SmartSlot Connection​

Yes, for ‘one to many’ hot replacement

Yes, for ‘one to many’ hot replacement

Dimensions (H×W×D)​

110 mm × 360 mm × 68 mm

110 mm × 360 mm × 68 mm (drop-in compatible)

Weight​

Approx. 0.95 kg

Approx. 0.95 kg

Technical Principles and Innovative Values:

The ICS TRIPLEX T8850/T8850C​ operates on the principle of centralized field wiring termination and maintenance facilitation within a TMR architecture.

Innovation Point 1: High-Density, Configurable Channel Grouping.​ The module consolidates 40 field wiring points into a single, organized unit . These channels are intelligently divided into five isolated groups of eight channels each . This grouping allows maintenance personnel to isolate and work on one section without affecting others, enhancing operational safety and flexibility during troubleshooting.

Innovation Point 2: “SmartSlot” Enabled Hot-Swap Functionality.​ A key innovation is the integrated SmartSlot connector . This allows a single upstream TMR output module to connect to the FTA. In the event an output module needs replacement, technicians can hot-swap it via this single connection point without touching any of the 40 field wires . This dramatically reduces mean time to repair (MTTR) and maintains system availability.

Innovation Point 3: Enhanced Reliability for Harsh Environments (T8850C).​ The T8850C​ variant introduces significant improvements for challenging installations :

Conformal Coating:​ The PCB is fully conformal coated, increasing salt-fog endurance from 96 hours to 500 hours, making it ideal for offshore or coastal applications.

Configurable OVP:​ Allows software selection of over-voltage protection trip points (28V, 32V, 36V), enabling use of the same FTA for different field voltage devices (e.g., 24V solenoids and 28V beacons).

Cold-Start Surge Clamp:​ Limits inrush current when field power is reapplied, preventing voltage dips that could affect other loop cards.

Enhanced EMC Immunity:​ Meets stricter standards for radiated and surge immunity, improving reliability in electrically noisy environments.

Application Cases and Industry Value

Case Study: Reducing Maintenance Downtime in a Gas Compressor Station ESD System.

A remote gas compressor station’s ESD system, based on Trusted TMR, controlled over 30 emergency shutdown valves. During a scheduled functional test, a fault was indicated on a T8451 digital output module responsible for closing a block of 8 valves.

Without a T8850:​ Technicians would need to trace and disconnect 8 individual wires from the faulty module, replace it, and then meticulously reconnect all 8 wires, a process prone to error and taking several hours under pressure, during which those valves were unavailable.

With the ICS TRIPLEX T8850:​ The 8 valves were wired to a single group on a T8850 FTA. The faulty T8451 module was connected to the T8850 via a single SmartSlot cable. Technicians simply disconnected this one cable, swapped the T8451 module, and reconnected the cable. The entire replacement took less than 30 minutes, and the integrity of the field wiring was never compromised. The station manager estimated that this setup avoided at least 4 hours of production downtime per incident, translating to significant revenue preservation and enhanced safety system readiness.

Related Product Combination Solutions

The ICS TRIPLEX T8850/T8850C​ is a key component within the Trusted TMR ecosystem, working in concert with:

Trusted TMR Output Modules:​ These are the signal sources. The FTA primarily interfaces with:

T8451:​ Trusted TMR 24 Vdc Digital Output Module .

T8461:​ Trusted TMR 24/48 Vdc Digital Output Module .

T8480:​ Trusted TMR Analog Output Module .

Trusted TMR Main Processors:​ The brain of the system, such as the T8110B​ or T8400​ series controllers, which execute the safety logic and command the output modules .

Trusted System Chassis & Power Supplies:​ The infrastructure that houses all modules, like the T8310/T8311​ expansion interface modules and redundant power supplies .

Output Power Distribution Unit (OPDU) T8290:​ Required when using field supply voltages above 32 Vdc to route power correctly .

Installation, Maintenance, and Full-Cycle Support

Installation:​ The FTA mounts on a standard DIN rail within a control or marshalling cabinet . Field wiring from devices is landed on its high-quality terminals (screw clamp for T8850. spring clamp for T8850C) . The connection to the Trusted output module is made via a pre-fabricated cable to the 96-circuit socket and the SmartSlot connector . Critical steps include ensuring proper 24V DC field power connection and verifying that the total load across channels does not exceed specifications .

Maintenance:​ The onboard LEDs provide immediate status of field power for each channel group . The primary maintenance advantage is the facilitated hot-swap of connected output modules. For the FTA itself, maintenance typically involves periodic visual inspection for secure connections and cleanliness. If a terminal or the entire FTA needs replacement, the module can be swapped offline by transferring field wires to a new unit.

Key Consideration for T8850C:​ Integration of the T8850C​ requires TriStation 1131 software version 4.9 or higher​ to access and configure its new features like selectable OVP . It is physically a drop-in replacement for the T8850 but requires a firmware/software update for full functionality.

We provide comprehensive support for the ICS TRIPLEX T8850/T8850C​ and the entire Trusted system. This includes system design consultation, supply of genuine modules and cables, installation guidance, software configuration support (especially for T8850C features), and troubleshooting assistance