Product Overview
Boasting 32 differential DC-coupled input points, the Triconex 3721 efficiently handles voltage signals in the ranges of 0 to 5 VDC or -5 to +5 VDC (with a ±6% tolerance). Its three independent channels operate in parallel, each performing signal conversion and transmitting data to main processor modules. A sophisticated mid-value selection mechanism in TMR mode filters out inconsistencies, ensuring only verified data drives system decisions. This design makes it indispensable for safety-critical operations where even minor errors could lead to significant losses.
Product Specifications
Parameter | Details |
Brand | Invensys Triconex |
Type | TMR (Triple-Modular Redundancy) |
Voltage Range | 0 to 5 VDC or -5 to +5 VDC, ±6% (selectable via TriStation software) |
No. of Input Points | 32 differential, DC-coupled |
Isolated Points | Yes |
Input Update Rate | 10 ms |
Resolution | 12 bits or 14 bits (programmable) |
Accuracy | < 0.15% of FSR (0° to 60° C) |
Input Resistance | 10 MΩ (DC), minimum |
Power-Off Resistance | 140 kΩ (DC), typical |
Common Mode Rejection | -85 dB (DC - 100 Hz) |
Common Mode Range | -12V to +12V peak |
Leg-to-Leg Isolation | 420 kΩ, typical |
Normal Mode Rejection | -3 dB @ 23 Hz; -8 dB @ 60 Hz; -14 dB @ 120 Hz |
Input Overrange Protection | 150 VDC/115 VAC continuous |
Current Range | 0-20 mA (with 250 Ω shunt resistor) |
Diagnostic Indicators | PASS, FAULT, ACTIVE, FIELD |
Color Code | Yellow |
Features
TMR Architecture for Superior Fault Tolerance
At the core of the Triconex 3721 lies its triple-modular redundancy design, eliminating single points of failure. Three distinct channels process signals independently, allowing the module to remain fully operational even with up to two channel faults. The mid-value selection algorithm ensures only consistent data is forwarded, a key feature for maintaining process stability in high-risk settings.
Channel Isolation for Uninterrupted Operation
Each of the 32 input points is electrically isolated, preventing fault propagation between channels. This isolation means a fault in one channel does not compromise others, reducing the likelihood of unplanned shutdowns—a critical advantage in 24/7 industrial operations.
Hot-Swap Functionality for Zero Downtime
Supporting hot-spare replacement, the Triconex 3721 enables on-the-fly module replacement without system shutdown. This capability is invaluable in industries like petrochemicals and power generation, where downtime can result in substantial financial losses.
Real-Time Diagnostics for Proactive Maintenance
Continuous diagnostics monitor every channel, with any anomaly triggering the FAULT indicator and chassis alarm. This instant alerts system allows maintenance teams to address issues before they escalate, minimizing operational disruptions.
Precision in Harsh Environments
With < 0.15% accuracy across 0° to 60° C and robust noise rejection (-85 dB common mode rejection), the module delivers reliable data even amid electrical interference from heavy machinery or high-voltage equipment.
Versatile Termination Options
Compatible with multiple external termination panels (ETPs)—including 9763-810 (voltage), 9761-210 (0–5 V), and 9761-410 (0–10 V)—the Triconex 3721 integrates seamlessly into existing setups, reducing installation complexity and costs.
Applications
Oil and Gas Operations
In refineries, pipelines, and offshore platforms, the Triconex 3721 integrates with emergency shutdown systems (ESD) and distributed control systems (DCS) to monitor pipeline pressure, crude flow rates, and storage tank levels. Its redundancy ensures uninterrupted data flow during critical processes like pumping and separation.
Chemical Processing
Within batch and continuous production lines, the module tracks reagent concentrations, reactor temperatures, and pH levels. Its compliance with SIL 3 standards makes it ideal for handling hazardous chemicals, where safety and regulatory adherence are non-negotiable.
Power Generation
Deployed in fossil fuel, nuclear, and renewable plants, it monitors turbine vibrations, steam pressure, and generator output. Reliable data transmission helps maintain grid stability and prevents costly equipment failures in power distribution networks.
Pharmaceutical Manufacturing
In sterile production environments, the Triconex 3721 monitors cleanroom temperature, humidity, and pressure, ensuring compliance with FDA and EMA guidelines. Its precision safeguards drug quality during formulation and packaging.
Marine and Offshore Engineering
Built to withstand saltwater exposure and vibration, it supports shipboard control systems and offshore rigs by monitoring engine performance, fuel consumption, and environmental conditions like sea temperature and pressure.
FAQ
Is the Triconex 3721 compatible with non-Triconex systems?
While optimized for the Invensys Triconex TMR Architecture System, the module can integrate with third-party systems via compatible termination panels, though full functionality is best achieved within Triconex ecosystems.
What is the typical delivery time for the Triconex 3721?
The module is in stock, with delivery times ranging from 2–5 business days for domestic orders and 7–14 days for international shipments. Contact sales for location-specific timelines.
How does the module handle voltage fluctuations?
With a ±6% tolerance on voltage ranges and robust overrange protection (150 VDC/115 VAC continuous), it remains stable amid minor voltage variations common in industrial grids.
Can the resolution be adjusted post-installation?
Yes, resolution (12 bits or 14 bits) can be reconfigured using TriStation software without physical module modification, allowing adaptation to evolving process requirements.
Does it require specialized training for installation?
Basic industrial control system training is recommended, though the module’s mechanical keying and clear labeling simplify installation. Manufacturer-provided guides offer step-by-step instructions.
What safety certifications does the Triconex 3721 hold?
It meets IEC 61508 (SIL 3), ISA 84, and ATEX standards, ensuring compliance in global high-risk industries such as oil, gas, and chemicals.
The Triconex 3721 TMR Analog Input Module stands as a testament to innovation in industrial automation, blending TMR technology, precision, and adaptability to thrive in the most demanding environments. Its focus on reliability and seamless integration makes it a cornerstone of safe, efficient industrial operations worldwide.
