Description
Product Overview
The Triconex 3721 is a triple modular redundant (TMR) analog input module engineered for Tricon safety instrumented systems (SIS). Designed for safety-critical ESD, F&G and turbine protection applications in oil & gas, petrochemical and power generation plants, this 32-point differential module acquires DC voltage signals from field transmitters. TMR fault-tolerant architecture prevents single-point failures and meets SIL3 safety requirements. It is compatible with Tricon v10.2 and newer chassis platforms.
Technical Specifications
| Item | Parameter |
|---|---|
| Part Number | 3721 |
| Manufacturer | Triconex (Schneider Electric) |
| Product Type | TMR Analog Input Module |
| Input Channels | 32 differential, DC-coupled |
| Input Range | 0–5 VDC / -5 ~ +5 VDC, software selectable |
| Resolution | 12-bit / 14-bit programmable |
| Input Update Rate | 10 ms |
| Accuracy | <0.15% of FSR @ 0°C ~ 60°C |
| Input Impedance | ≥10 MΩ DC |
| Common Mode Rejection | -85 dB (DC–100 Hz typical) |
| Power Supply | 24 VDC (18–30 VDC operating range) |
| Safety Level | SIL 3 Certified (IEC 61508) |
| Operating Temp | -40°C ~ +70°C |
| Certifications | CE, CSA, ATEX, IECEx |
| Color Code | Yellow module faceplate |
Key Features
- Triple Modular Redundant (TMR) voting architecture for fault tolerance and high availability in safety loops.
- 32 differential DC voltage inputs, channel-level diagnostics to detect open circuit, short circuit and overrange conditions.
- Programmable resolution and input range configured via TriStation software.
- High common-mode noise rejection, minimizes ground loop interference between field sensors and safety rack.
- Hot-swappable design, allows module replacement without system shutdown under qualified maintenance procedures.
- Supports hazardous area installation with applicable explosion-proof certifications.
Installation Notes
- Only install into Tricon chassis running firmware version v10.2 or later.
- Verify backplane power and chassis ground integrity before inserting the module.
- Pair with proper Triconex termination assemblies for field wiring.
- Separate analog signal cables from high-voltage AC power wiring to reduce EMI.
- Perform channel calibration and loop checkout after module replacement.
- Follow site SIS lockout/tagout procedures for all maintenance activities.
Testing Procedure
- Visual inspection: Check PCB, connectors and housing for physical damage, corrosion or bent pins.
- Insert module into Tricon rack, apply 24VDC rack power, confirm module healthy status LED.
- Use precision voltage calibrator to inject known -5V, 0V, +5V reference signals to each differential channel.
- Compare module reading in TriStation against calibrator values to verify accuracy within <0.15% FSR.
- Trigger fault simulation (open/short channel) to validate built-in diagnostic alarms.
- Record test data, sign off and tag module for service or stock.
FAQ
Q: What system version does Triconex 3721 support? A: It works on Tricon v10.2 and newer TMR safety system chassis; not compatible with older v9 and earlier platforms.
Q: Is Triconex 3721 hot swappable? A: Yes, hot swap is permitted under controlled maintenance conditions for Tricon SIS racks.
Q: What safety class does this module achieve? A: SIL 3 per IEC 61508, suitable for emergency shutdown and fire & gas safety loops.
Q: Can it read 4-20mA directly? A: No, this module accepts DC voltage signals. 4–20mA transmitters need external precision resistors to convert current to voltage.
Start Chat
Send an Email
