Description

The Triconex AIH 3723X is a high-density, fault-tolerant analog input module designed for the critical demands of Tricon Safety Instrumented Systems (SIS) and Emergency Shutdown (ESD) systems. Manufactured by Triconex, now part of Schneider Electric, this module serves as the primary interface for acquiring critical continuous process signals from field transmitters, converting them into digital data for processing by the system’s triple modular redundant (TMR) controllers. The core function of the Triconex AIH 3723X is to ensure the integrity of analog signals such as 4-20 mA current loops and 0-10 V DC voltages, which represent vital process variables like pressure, temperature, flow, and level.

As a cornerstone of the renowned Tricon V9/V10/V11 platform, the AIH 3723X is engineered for maximum reliability and safety integrity, capable of meeting SIL 3 requirements as per IEC 61508 and IEC 61511 standards. Its design is integral to maintaining continuous process monitoring and enabling precise automatic protective actions in high-hazard environments. The module’s value lies in its ability to provide highly accurate and dependable data acquisition, which forms the basis for all safety-related logic decisions within the TMR architecture, thereby protecting personnel, assets, and the environment.

The module operates within a TMR configuration, where three identical Triconex AIH 3723X modules work in parallel. This architecture allows the main processors to perform continuous voting on the input data, instantly identifying and compensating for any discrepancy or fault in a single channel or module without interrupting the process. This robust design ensures unparalleled availability and prevents spurious trips, making it an indispensable component for any mission-critical automation safety solution.

AIH 3723X TRICONEX

Technical Specifications

Parameter Name	Parameter Value
Product Model	AIH 3723X
Manufacturer	Triconex (Schneider Electric)
Product Type	Analog Input Module
Number of Channels	16 single-ended or 8 differential (configurable)
Input Signal Types	4-20 mA, 0-5 V DC, 0-10 V DC, 1-5 V DC
Resolution	16-bit
Accuracy	±0.1% of full scale
Input Impedance	250 Ω (for current signals), >1 MΩ (for voltage signals)
Update Rate per Channel	50 ms (maximum)
Common Mode Rejection	>120 dB
Operating Temperature	-40°C to +70°C (-40°F to +158°F)
Relative Humidity	0 to 95% (non-condensing)
Power Consumption	1.5 W (typical)
Hardware Diagnostics	Channel fault detection, open wire, short circuit, over-range/under-range

Main Features and Advantages

The Triconex AIH 3723X is distinguished by its uncompromising design for safety and reliability. Its most prominent feature is its seamless integration into the Triple Modular Redundant (TMR) architecture. Three independent input channels process each signal, and the system uses a two-out-of-three (2oo3) voting mechanism to provide a single, valid value to the main processor. This design ensures continuous operation even if one entire module fails, guaranteeing extremely high system availability and eliminating single points of failure.

Advanced diagnostic capabilities: The module incorporates comprehensive self-diagnostics that continuously monitor the health of each channel and the module itself. It can detect critical faults such as transmitter wire breaks, short circuits, signal out-of-range conditions, and internal hardware failures. These diagnostics are reported in real-time to the control system, allowing for immediate maintenance alerts and preventing undetected dangerous failures, which is a cornerstone of achieving SIL 3 safety ratings.

The Triconex AIH 3723X offers exceptional flexibility and ease of use. Each channel is individually configurable via software (TriStation 1131) for signal type, range, alarm limits, and filtering. This high channel density allows for a reduction in overall system footprint and cost per point. Furthermore, the module is designed for hot-swappable replacement in supported configurations, enabling maintenance and module swaps to be performed without taking the entire safety system offline, thus minimizing process downtime and enhancing operational efficiency.

Application Field

The Triconex AIH 3723X is deployed in industries where process safety is non-negotiable and system failure can have catastrophic consequences. Its primary application is within Safety Instrumented Systems (SIS) and Emergency Shutdown (ESD) systems across the oil and gas sector. Here, it is used to monitor critical parameters on offshore platforms, in refineries, and along pipelines, such as wellhead pressure, compressor discharge temperature, and fire and gas detection system levels. The reliable data provided by the AIH 3723X is fundamental for initiating automatic shutdowns to prevent blowouts, fires, or explosions.

In the chemical and petrochemical industries, the module protects large-scale reactors, distillation columns, and storage facilities. It accurately acquires analog signals related to concentration, flow rates, and vessel levels, triggering safety actions if processes deviate from their safe operating limits. Similarly, in power generation, particularly in nuclear and combined-cycle gas turbine plants, the Triconex AIH 3723X ensures safe operation by monitoring turbine vibration, bearing temperature, and boiler feedwater flow, initiating trips to protect multi-million dollar equipment from damage.

Beyond these, it finds critical use in pharmaceutical manufacturing, where batch processes require strict environmental control, and in metallurgical plants for monitoring furnace temperatures. In every scenario, the Triconex AIH 3723X solves the fundamental problem of acquiring analog process signals with utmost integrity and reliability, forming the sensory foundation upon which entire safety loops are built and operated.

AIH 3723X TRICONEX

Related Products

Triconex 3008: The main TMR processor module that works in conjunction with the AIH 3723X to execute safety logic.

Triconex 3503E: A complementary analog output module for sending control signals to final elements like control valves.

Triconex 3664: A digital input module for reading discrete status signals within the same TMR system.

Triconex 4351B: A communication module that allows the TMR system, including the AIH 3723X data, to interface with plant DCS and other networks.

Triconex 8312: A robust power supply module designed to deliver clean, redundant power to the chassis housing the I/O modules.

Triconex AIH 3722: A similar analog input module with potentially different channel count or specifications for varied application needs.

Triconex MTL 5721: An intrinsic safety barrier module often used in conjunction with the AIH 3723X to interface with transmitters in hazardous areas.