中文版
Phone: 
Email: 
WhatsApp: Description
TRICONEX 3721A Analog Input Module
Product Overview
The TRICONEX 3721A is a high-precision analog input module designed for TRICONEX’s Tricon safety instrumented system (SIS), a critical platform for industrial safety and process control. It serves as a key interface between field sensors (such as pressure transmitters, temperature probes, and flow meters) and the SIS controller, converting continuous analog signals into digital data that the system uses to monitor process variables and execute safety-critical decisions. This functionality is essential for maintaining operational integrity in high-risk environments where precision and fault tolerance are paramount.
The TRICONEX 3721A features 16 differential analog inputs, supporting voltage and current ranges commonly used in industrial sensors, including 4–20mA, 0–20mA, 0–5V, and ±5V. Its triple-modular redundancy (TMR) architecture ensures that if one channel fails, the module continues operating using the remaining two, preventing system shutdowns and meeting Safety Integrity Level (SIL) 3 requirements. Each channel includes galvanic isolation (250V AC) from the backplane, protecting against electrical noise and ground loops common in facilities with heavy machinery or electromagnetic interference.
As part of the Tricon ecosystem, the TRICONEX 3721A integrates seamlessly with components like the TRICONEX 3503E (main processor module), TRICONEX 3625C1 (redundant power supply), and TRICONEX 3700 (digital output module). It operates in temperatures from 0°C to 60°C, resists dust, vibrations, and humidity, and is certified for use in hazardous areas (ATEX, IECEx). Its compact design (160mm × 100mm × 30mm) fits into standard Tricon racks, while LED indicators for each channel provide real-time status updates, simplifying troubleshooting.
Whether used in oil refineries, chemical plants, or nuclear power facilities, the TRICONEX 3721A ensures accurate and timely data collection, forming the foundation of robust safety systems that prevent accidents and protect personnel.
Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | 3721A |
| Manufacturer | TRICONEX |
| Product Type | 16-Channel Differential Analog Input Module |
| Series | Tricon Safety Instrumented System |
| Number of Channels | 16 (differential) |
| Input Ranges | 4–20mA, 0–20mA, 0–5V, ±5V |
| Resolution | 16 bits |
| Accuracy | ±0.1% of full scale (0°C–60°C) |
| Isolation | 250V AC (channels to backplane) |
| Physical Dimensions | 160mm (L) × 100mm (W) × 30mm (D) |
| Weight | 0.5 kg |
| Operating Temperature | 0°C to 60°C |
| Humidity Resistance | 5–95% non-condensing |
| Safety Certification | SIL 3, IEC 61508, ATEX, IECEx |
| Country of Origin | United States |
3721A
Related Products
- TRICONEX 3503E: The main processor module of the Tricon SIS, which processes data from the 3721A to execute safety logic and trigger protective actions.
- TRICONEX 3625C1: A redundant power supply module that provides stable 24V DC power to the 3721A and other Tricon components, ensuring continuous operation.
- TRICONEX 3700: A digital output module that works with the 3721A in closed-loop systems—analog data from the 3721A prompts the CPU to activate outputs like shutdown valves via the 3700.
- TRICONEX 3511: A 16-channel digital input module that complements the 3721A in mixed-signal systems, handling discrete sensors alongside analog inputs.
- TRICONEX 4409: A communication module that transmits data from the 3721A to SCADA systems, enabling remote monitoring of process variables.
- TRICONEX 8312: A rack assembly that houses the 3721A and other modules, providing structural support and backplane connectivity.
- TRICONEX 3721: A predecessor to the 3721A with 12-bit resolution, serving as a legacy alternative for older Tricon systems.
Main features and advantages
Triple-modular redundancy (TMR): The 3721A uses three independent channels to process signals. If one channel fails, the other two continue operating, ensuring no single point of failure. This design meets SIL 3 requirements, making it ideal for critical applications like nuclear reactor coolant monitoring, where failure could lead to catastrophic consequences.
High precision and flexibility: With 16-bit resolution and ±0.1% accuracy across its operating temperature range, the module ensures precise conversion of analog signals. It supports 4–20mA, 0–20mA, 0–5V, and ±5V inputs, accommodating sensors from pressure transmitters to thermocouples without additional signal converters.
Electrical isolation and noise immunity: Each channel features 250V AC isolation from the backplane, blocking electrical noise from motors, pumps, or welders. Its differential input design further reduces interference, ensuring reliable signal acquisition in noisy environments like chemical plants.
Industrial durability: The 3721A operates in temperatures from 0°C to 60°C and resists dust, vibrations, and humidity. It performs reliably in harsh settings—from freezing LNG terminals to humid offshore platforms—reducing unplanned downtime.
Clear status monitoring: LED indicators on the front panel show the input status of each channel (normal/fault). This allows technicians to quickly identify issues like broken wires or faulty sensors without opening the rack, speeding up troubleshooting in emergency situations.
Easy integration with Tricon SIS: The 3721A fits directly into Tricon racks like the 8312, connecting to the backplane for power and data. It configures easily via TRICONEX’s TriStation 1131 software, with pre-built function blocks for common analog signal processing tasks, reducing setup time.
3721A
Installation and maintenance
Pre-installation preparations: Power off the Tricon rack (e.g., 8312) before installing the 3721A. Verify that the power supply (e.g., 3625C1) provides 24V DC within the 18–30V range. Inspect the module for physical damage, ensuring connectors are clean and intact. Use an anti-static wristband to handle the module to avoid static damage to internal components. Align the module’s mounting brackets with the rack slots and secure it with M6 screws.
Maintenance suggestions: Inspect the 3721A quarterly. Check sensor connections for looseness and wipe dust from the module’s surface with a dry cloth. Monitor LED indicators to ensure all channels show normal operation—flashing or off LEDs may indicate a sensor fault. Test input signals annually using a calibrated voltage or current source to verify accuracy. If errors persist after sensor checks, replace the 3721A following proper shutdown procedures to avoid disrupting the Tricon SIS, as sudden removal could trigger safety alarms.
Application fields
The TRICONEX 3721A is widely used in industries requiring precise monitoring of continuous process variables:
In oil and gas production, it monitors pressure and temperature signals from wellheads and pipelines. For example, in offshore platforms, the 3721A collects data from downhole sensors to detect abnormal pressure spikes, triggering the SIS to close valves via the 3700 module and prevent oil spills.
In chemical processing, the module tracks reactor temperature and flow rates. It ensures cooling systems maintain optimal conditions, sending alerts to the controller if parameters deviate from safe ranges—critical for preventing runaway reactions in petrochemical plants.
In nuclear power plants, the 3721A monitors coolant temperature and level in reactor cores. Its TMR design ensures reliable signal transmission to the SIS, which initiates shutdown procedures if unsafe conditions are detected, protecting workers and the environment.
In pharmaceutical manufacturing, the module measures pH levels and conductivity in sterile processing lines. It ensures compliance with regulatory standards by providing real-time data to quality control systems, minimizing the risk of product contamination.
3721A
Product guarantee
Our company offers a one-year quality warranty service for the 3721A, covering hardware malfunctions not caused by human factors. During the warranty period, if the product shows abnormal performance or functional failure, we will provide replacement services. In addition, for discontinued models or urgent demands, relying on our global supply chain network, we can quickly respond to customers’ procurement needs for scarce spare parts, and provide reliable services to support the continuous and stable operation of industrial systems.
Our company is a leading enterprise in the industrial control industry, established in 2007, has been 17 years. The company type is an import and export trade distribution company, mainly selling major brands of industrial control parts, there are many unpopular discontinued models, with a large stock. Our company has the advantage of supply channels, a large number of spot, to meet the needs of customers anxious to find spare parts. Our main business includes the distribution and trade of PLC modules, DCS cards, ESD system cards, vibration monitoring system cards, turbine control system modules, gas generator spare parts, instruments and other products.
Whatsapp:+86 18859254943
E-mail :sales@ygplc.com
E-mail :sales@ygplc.com
