TRICONEX 3700A TMR Triple Modular

Product Description

3700A is a core analog signal acquisition module developed by Triconex (now under Schneider Electric) exclusively for Tricon series triple modular redundant safety instrumented systems (SIS). 

It adopts the industry-leading TMR fault-tolerant triple-circuit voting architecture, which executes signal collection through three completely independent hardware loops and outputs valid data 

via median value voting algorithm to eliminate single-point hardware failure risks.

This module is equipped with 32 channels of DC-coupled differential analog inputs, mainly receiving 0–5VDC voltage signals on site, and can match 250Ω external resistors to collect standard 4–20mA 

transmitter signals from pressure, flow, temperature and liquid level transmitters. It converts analog field signals into digital values and transmits them to the Tricon main processor for safety interlock 

logic judgment, emergency shutdown (ESD) protection, fire and gas protection and process trip control. The board supports online hot-swap replacement without system shutdown, full-channel 

open/short-circuit self-diagnosis, conformal coated PCB, standard large rack plug-in installation. It is a mandatory safety spare part for oil & gas refineries, chemical plants, thermal power units, 

offshore platforms and other high-risk process industry safety control systems, fully complying with IEC 61508 SIL3 functional safety standards.

Technical Specifications

Model: 3700A, Brand: Triconex (Schneider Electric), Origin: United Kingdom

System Compatibility: Tricon Classic / Tricon CX SIS Safety Controller Rack

Redundancy Architecture: TMR Triple Modular Redundant three-way voting fault tolerance

Input Channels: 32 differential DC-coupled analog input points (non-channel isolated)

Standard Input Range: 0–5VDC DC voltage, 4–20mA current (with external 250Ω resistor)

A/D Conversion Resolution: 12-bit effective conversion

Overall Measurement Accuracy: ≤0.15% full scale range (0℃ ~ +60℃ working environment)

Input Impedance: Minimum 30MΩ high input impedance per channel

Module Scan Update Rate: 55ms full loop scanning for all 32 channels

Common Mode Rejection Ratio: ≥80dB (DC~100Hz frequency band)

Power Supply: Powered by Tricon rack internal backplane bus

Max Power Consumption: Less than 4W

Safety Certification: TÜV SIL3 (IEC 61508), FMEDA, CE, UL, ATEX hazardous area approval

Operating Temperature: 0℃ ~ +60℃ continuous full-load operation

Storage Temperature: -40℃ ~ +85℃

Ambient Humidity: 5%–95% non-condensing, anti-corrosion three-proof conformal coated circuit board

Protection Class: IP20, only installed inside industrial control cabinet

Mounting: Standard Tricon chassis slot plug-in hot-swappable installation

Net Weight: Approx. 2.5kg

Physical Dimension: 297 × 108 × 185mm

Key Features

Core TMR triple modular redundant fault-tolerant design, single circuit or single component damage will not affect normal signal collection and system safety logic execution, extremely 

high safety integrity for critical process protection.

32 high-density differential input channels, large signal acquisition capacity, effectively reduce the number of rack slots occupied by analog acquisition modules for large-scale SIS systems.

Complete channel-level hardware self-diagnosis function, real-time detect sensor open circuit, short circuit, module internal circuit abnormality, lock fault channel and upload fault codes to upper 

TriStation software for maintenance reminder.

Full support for online hot plug and replacement, faulty module can be directly pulled out and replaced during system running without powering down the safety system, minimizing production

 interruption risk.

Optimized common-mode interference suppression circuit, strong anti-electromagnetic interference capability, stable measurement performance under strong harmonic and variable frequency 

interference in chemical plant and power plant workshops.

Perfectly matched with TriStation 1131 programming configuration software, signal range and channel alarm parameters can be remotely set without hardware jumper adjustment.

Strictly certified SIL3 functional safety level, fully meet the safety regulatory requirements of petrochemical, natural gas and thermal power industry ESD emergency shutdown systems.

Rugged industrial-grade aluminum casing and moisture-proof vibration-proof coating, support long-term 24/7 non-stop stable operation in high-temperature, dusty central control room environment.