Description
1. Overview
Triconex AIH 3723X is a SIL 3 certified high-density HART analog input module designed exclusively for the TMR (Triple Modular Redundant) safety system, tailored for Safety Instrumented Systems (SIS), Emergency Shutdown Systems (ESD) and Fire & Gas (F&G) systems in process industries.This 16-channel high-precision analog acquisition unit supports simultaneous collection of standard 4–20 mA industrial analog signals and HART intelligent protocol signals, and is fully compatible with Tricon TMR triple modular redundant safety architecture.The module features safety fault tolerance, galvanic isolation per channel, full-channel self-diagnosis, transparent transmission of HART data and fail-safe protection. It stably acquires process analog parameters such as field pressure, temperature, liquid level and flow, as well as digital diagnostic information from smart instruments.Certified to IEC 61508 SIL 3, the highest industrial functional safety standard, it is widely deployed in high-risk process sectors including petrochemicals, natural gas, oil & gas storage and transportation, and power generation. It delivers highly reliable analog data for unit process interlock, over-limit protection, safety monitoring and predictive maintenance.
2. Technical Features
2.1 16-Channel High-Density Acquisition with Native HART Smart Signal Compatibility
A single module integrates 16 independent analog input channels with high channel density, effectively reducing cabinet space occupation and cutting system hardware and wiring costs.Each channel natively supports standard 4–20 mA analog signals and HART 7 communication protocol. Besides basic process analog values, it retrieves digital data from smart transmitters including equipment diagnostics, range configuration, device status and fault codes. It unifies process parameter monitoring and instrument health management, ideal for centralized supervision of massive smart instruments on large-scale plants.
2.2 TMR Triple Redundant Architecture with SIL 3 Grade Fault Tolerance
Adopting Triconex proprietary Triple Modular Redundant hardware architecture, three independent computing links perform synchronous sampling and majority voting output. It automatically filters out data from single-point faults to prevent incorrect values, false trips or failure to trip caused by single hardware failure.The fail-safe design complies with SIL 3 functional safety requirements. Faults on a single channel or link will not propagate or compromise overall system safety, meeting zero-tolerance safety standards for high-risk chemical and oil & gas facilities and ensuring long-term stable operation of safety loops.
2.3 Full Channel Galvanic Isolation with Excellent Anti-Interference Performance
Complete galvanic isolation is implemented between channels and between the field side and logic side, with a dielectric withstand voltage of 2300 VAC per channel. It effectively eliminates ground loop currents, voltage surges and electromagnetic noise from the field.Built-in high-precision filtering and signal conditioning algorithms suppress signal fluctuation and interference generated by inverters and frequent switching of heavy-duty equipment. It greatly improves acquisition stability and measurement accuracy for long-distance wiring and eliminates spurious interlocks triggered by signal drift and jitter.
2.4 Comprehensive Self-Diagnosis for Predictive Maintenance and Fault Traceability
Real-time online self-diagnosis across all channels accurately detects open circuits, short circuits, out-of-range signals, abnormal readings, HART communication loss and module hardware faults.It supports real-time fault alarming, Sequence of Events (SOE) timestamped logging and precise fault code positioning for rapid troubleshooting of instrument loops and module anomalies.Remote instrument diagnosis via HART enables early identification of instrument aging, drift and potential faults to facilitate predictive maintenance and drastically reduce the risk of unplanned plant shutdowns.
2.5 Industrial Robust Design with Hot-Swap Maintenance Without Shutdown
Constructed as an industrial ruggedized modular unit, it adapts to harsh temperature, humidity and electromagnetic conditions inside control cabinets with dustproof, moisture-proof, vibration-resistant and temperature-cycle resistant properties, supporting 24/7 non-stop continuous operation.Hot-swappable replacement is available without system shutdown or power interruption for faulty module maintenance and swapping, maximizing continuous production and minimizing downtime losses to fit unattended long-term operation of industrial facilities.
3. Specification Parameters
3.1 Basic Model Information
- Model: AIH 3723X
- Brand & Series: Triconex Tricon TMR Triple Modular Redundant Safety System
- Module Type: SIL 3 16-Channel HART Analog Input Module
- Channel Configuration: 16 isolated analog input channels with HART protocol support
- Core Functions: 4–20 mA analog signal acquisition, HART smart data reading, process parameter monitoring, fault diagnosis and interlock data output
- Compatible Systems: Triconex SIS / ESD / F&G Safety Instrumented Systems
3.2 Acquisition & Electrical Parameters
- Input Signal: Standard 4–20 mA DC analog signal
- Communication Protocol: HART 7 intelligent communication protocol
- Sampling Precision: 16-bit high-resolution AD conversion, overall accuracy better than ±0.1% Full Scale
- System Scan Cycle: Approx. 220 ms for full channel scan with fast response
- Isolation Rating: Galvanic isolation between channels and field/logic sides, 2300 VAC dielectric withstand for 1 minute
- Fault Tolerance Mechanism: TMR triple-link majority voting, single-point fault isolation and fail-safe output
3.3 Communication & System Parameters
- System Backplane Bus: Tricon proprietary TriBus triple redundant high-speed bus
- Data Functions: Real-time parameter upload, transparent transmission of HART instrument diagnostic data, SOE event logging and fault log storage
- Configuration Method: Customizable channel parameters, measurement ranges and alarm thresholds via dedicated Triconex configuration software
- Operation Architecture: Triple redundant synchronous sampling, voting output and transparent failover upon faults
3.4 Environmental Parameters
- Operating Temperature: 0 ℃ ~ +55 ℃
- Storage Temperature: -40 ℃ ~ +85 ℃
- Operating Humidity: 5% ~ 95% RH (non-condensing)
- EMC Compliance: Meets industrial electromagnetic compatibility standards for heavy EMI industrial environments
- Operation Mode: 24-hour non-stop continuous safety operation
3.5 Mechanical & Maintenance Parameters
- Mounting Method: Standard rack mounting on Tricon system backplane
- Maintenance Feature: Hot-swappable online replacement without system shutdown
- Status Indication: Onboard LEDs for run status, communication, faults and channel abnormalities
- Diagnostic Capabilities: Full-channel short/open circuit detection, out-of-range diagnosis, HART communication diagnosis, hardware self-test and fault traceability
4. Working Principle
Based on the TMR triple redundant safety architecture, Triconex AIH 3723X executes a closed-loop safety acquisition workflow: field signal collection → galvanic isolation & filtering → high-precision AD conversion → triple-link voting verification → data upload → fault diagnosis & protection.
During operation, 16 isolated channels synchronously collect 4–20 mA process signals including field pressure, temperature, liquid level and flow, while retrieving device status, diagnostic parameters and configuration data from smart transmitters via HART.After galvanic isolation, noise reduction filtering and 16-bit analog-to-digital conversion, signals are processed and voted by three redundant computing paths to reject interference and single-point faulty samples, outputting accurate and standardized process data.
The module continuously compares measured values against preset interlock thresholds to provide core data for over-limit alarming, safety interlocks and emergency shutdown.
5. Application Scenarios
5.1 SIS Safety Instrumented Systems for Petrochemical Industry
Widely used in ESD emergency shutdown and process interlock systems of refineries, chemical plants and coal-to-chemical facilities. It performs batch acquisition of safety process parameters (temperature, pressure, liquid level, flow) for critical equipment such as reactors, distillation columns and furnaces, and monitors the health status of smart instruments. It enables reliable interlock protection against over-temperature, over-pressure and abnormal liquid level to prevent safety incidents including leakage and explosion and guarantee safe chemical production.
5.2 Oil & Gas Storage, Transportation and Natural Gas Processing Control Systems
Deployed in safety monitoring systems for natural gas purification plants, long-distance pipelines and oil & gas depots. It collects key analog parameters including pipeline pressure, valve house conditions, tank level and medium temperature. HART diagnostic functions support remote operation and maintenance of field smart instruments to stabilize process control and interlock reliability, eliminating risks such as overpressure and leakage during transportation.
5.3 Safety Monitoring Systems for Power Generation Industry
Applied to SIS safety systems of thermal power, cogeneration and combined-cycle power stations. It collects process parameters including unit temperature, pressure, liquid level and flow and participates in logic control for unit process protection, auxiliary equipment interlock and over-limit shutdown. Redundant high-reliability acquisition prevents unintended unit actions and unplanned outages caused by signal anomalies to sustain stable continuous power generation.
5.4 Safety Systems for Fine Chemical & Pharmaceutical Processes
Suitable for high-risk reaction units in fine chemical and pharmaceutical manufacturing. Meeting explosion-proof, cleanroom and high-precision monitoring requirements, it accurately acquires core process parameters of reactors and heat exchangers. Full-channel isolation and strong anti-interference adapt to complex workshop conditions and satisfy strict compliance and safety control standards for the sector.
5.5 Intelligent Instrument Operation & Maintenance Systems for Industrial Plants
Leveraging HART intelligent data collection and comprehensive diagnostic functions, it enables online condition monitoring, fault prediction and health evaluation of large quantities of field transmitters. It replaces traditional manual inspection with predictive maintenance, reduces process fluctuation and interlock hazards originating from instrument faults, and elevates automation and intelligent O&M levels of industrial facilities.
