Description
TRICONEX 3721 Analog Input Module
Product Overview:
The TRICONEX 3721 is a high-density, triple modular redundant (TMR) analog input module designed for the Tricon safety instrumented system. It serves as the critical interface between the field’s analog instrumentation and the TMR controller. Its primary function is to acquire standard 4-20 mA or 0-5 V DC signals from safety-critical transmitters—such as pressure, level, flow, and temperature transmitters—convert them into digital data, and present three independent, isolated readings to the three main processors for voting. This module is engineered for high reliability, accuracy, and diagnostic coverage, forming an essential part of the signal chain in SIL 3 certified safety loops.
Key Features and Advantages:
Triple-Channel Signal Acquisition and Isolation:
The TRICONEX 3721 provides three completely isolated input circuits for each connected field channel. Each of the three internal TMR channels independently reads, conditions, and digitizes the incoming analog signal. This hardware-level isolation ensures that a fault on one channel (e.g., a short circuit or power issue) cannot affect the readings on the other two channels, preserving the integrity of the TMR architecture and enabling true 2-out-of-3 (2oo3) voting on the input value.
High Accuracy and Advanced Diagnostics:
The module is designed for precise measurement, featuring high-resolution analog-to-digital conversion to ensure that even small changes in the process variable are accurately detected. It incorporates extensive continuous diagnostics, including signal wire break detection, out-of-range checks, and module hardware fault detection. It can also power the connected 2-wire field transmitters with a loop supply, and diagnostics can monitor for loop integrity issues, providing early warning of potential transmitter or wiring failures.
Hot Replacement and Online Maintenance:
The TRICONEX 3721 supports online, hot-replacement maintenance. If diagnostics indicate a fault in the module, it can be safely removed and replaced while the Tricon system remains online and operational. The two remaining healthy channels for each input will continue to provide valid data for voting, ensuring the safety function remains available, which is crucial for maximizing system uptime in continuous processes.
Certified for Safety-Critical Applications:
As a component of the Tricon TMR system, the TRICONEX 3721 is designed and certified to contribute to overall system safety integrity levels up to SIL 3 according to IEC 61508 and IEC 61511 standards. Its high hardware fault tolerance, comprehensive diagnostics, and proven in-service history make it suitable for the most demanding safety applications.
Technical Specifications:
|
Feature
|
Specification
|
|---|---|
|
Product Model
|
|
|
Module Type
|
TMR Analog Input Module
|
|
Input Type
|
4-20 mA, 0-5 V DC (selectable per channel)
|
|
Number of Channels
|
8 channels (triplicated, 24 total inputs)
|
|
Isolation
|
Channel-to-channel and channel-to-system isolation
|
|
Loop Power
|
Provides 24 V DC loop power for 2-wire transmitters
|
|
Diagnostics
|
Open wire, over-range, under-range, module fault
|
|
Hot Replacement
|
Supported
|
Application Areas:
The TRICONEX 3721 is used wherever high-integrity analog signal acquisition is required in a safety instrumented system. Its primary applications are in Emergency Shutdown (ESD) and Fire & Gas (F&G) systems within oil & gas platforms, refineries, and pipelines to monitor pressures, levels, and gas concentrations. It is also critical in Burner Management Systems (BMS) to read furnace draft pressure and fuel flow, and in Turbomachinery Control (TMC) systems to monitor vibration, speed, and temperature for critical equipment protection.
Related Products:
TRICONEX 3704E:
A high-density TMR digital input module. It serves a complementary function to the TRICONEX 3721, acquiring discrete on/off signals from devices like pressure switches, emergency stop buttons, and flame detectors, forming the digital input side of the safety system.
TRICONEX 3805E:
A high-density TMR digital output module. This module executes the voted safety commands from the controller, driving final elements like solenoid valves or motor starters. Together with the TRICONEX 3721 (for monitoring) and the 3805E (for action), they form a complete safety loop.
TRICONEX 4351B:
The Main Processor Module. The TRICONEX 3721 analog input module connects directly to the TMR bus managed by the TRICONEX 4351B. The processor reads the three independent analog values from the 3721, performs a mid-value selection vote, and uses the result in the safety logic application.
Other related models:
| TRICONEX | 3101 | Trident Main Processor |
| TRICONEX | 3201 | Trident Communication Module |
| TRICONEX | 3351 | Trident Analog Input Module |
| TRICONEX | 3481 | Trident Analog Output Module |
| TRICONEX | 3301 | Trident Digital Input Module |
| TRICONEX | 3401 | Trident Digital Output Module |
| TRICONEX | 3381 | Trident Pulse Input Module |
| TRICONEX | 2281 | Trident Expansion Module |
| TRICONEX | 2101 | Trident Main Processor Baseboard |
| TRICONEX | 2351 | Trident Analog Input Module Baseboard |
| TRICONEX | 2481 | Trident Analog Output Module Baseboard |
| TRICONEX | 2301 | Trident Digital Input Module Baseboard |
| TRICONEX | 2401 | Trident Digital Output Module Baseboard |
| TRICONEX | 2381 | Trident Pulse Input Module Baseboard |
| TRICONEX | 8111 | Expansion Rack |
| TRICONEX | 8110 | Main Rack |
| TRICONEX | 9000 | I/O Bus Expansion Cable |
| TRICONEX | 3700A | Analog Input Module |
| TRICONEX | 3805E | Analog Output Module |
| TRICONEX | 4351B | Communication Module |
| TRICONEX | 3625 | Digital Output Module |
| TRICONEX | 9662-610 | Digital Output Terminal Block |
| TRICONEX | 3721 | Analog Input Module |
| TRICONEX | 3511 | Frequency Module |
| TRICONEX | 4351 | Communication Module |
| TRICONEX | 9563-810 | DI terminal block (digital input terminal block) |
| TRICONEX | 7400-143 | DO terminal block |
| TRICONEX | 9761-210 | AI terminal block |
| TRICONEX | Power supply (for main unit rack, expansion and RXM rack) | |
| TRICONEX | 8310 | Power Supply (for Main Rack, Expansion, and RXM Racks) |
| TRICONEX | 8311 | Supports all power requirements; provides NO, C, and NC alarm contacts. Voltage: 24VDC. |
| TRICONEX | 8312 | Power module: Supports all power requirements; provides NO, C, and NC alarm contacts. Voltage: 230VAC. |
| TRICONEX | Main processor | |
| TRICONEX | 3004 | Executes control program and votes on inputs and outputs |
| TRICONEX | 3005 | Executes control program and votes on inputs and outputs |
| TRICONEX | 3006 | Executes control program and votes on inputs and outputs |
| TRICONEX | 3007 | Executes control program and votes on inputs and outputs |
| TRICONEX | 3008 | Executes control program and votes on inputs and outputs |
| TRICONEX | Numeric input | |
| TRICONEX | 3501E/T | Isolated, non-common. Voltage: 115VAC/VDC. Number of input points: 32 |
| TRICONEX | 3502E | 8 points per group, shared, with self-test function. Voltage: 48VAC/VDC. Number of input points: 32 |
| TRICONEX | 3503E | Digital input module. 8 points per group, shared, with self-test function. Voltage: 24VAC/VDC. Number of input points: 32 |
| TRICONEX | 3533E | 24VAC/DC digital input module, non-common, simplified type. |
| TRICONEX | 3504E | High-density—common, DC-coupled. Voltage: 24/48VDC. Number of input points: 64 |
| TRICONEX | 3505E | Low threshold voltage, with self-test, common. Voltage: 24VDC. Number of input points: 32 |
Reviews
There are no reviews yet.