Triconex 3674 Digital Input/Output 24VDC | Invensys Tricon

TRICONEX 3674 Dual Digital Output Module — 32 Points, 24 VDC

The TRICONEX 3674 is a 32-point dual digital output module for Triconex Tricon safety systems. Operating at 24 VDC, it provides opto-isolated, commoned outputs with voltage-loopback diagnostics that verify each output switch independently of the load presence. The dual output architecture provides sufficient redundancy to ensure safe operation while optimizing cost for safety-critical control programs where maximum TMR availability is not required.

• Type: Dual Digital Output (DO)
• Output Points: 32, commoned
• Nominal Voltage: 24 VDC
• Voltage Range: 16–30 VDC
• Maximum Voltage: 36 VDC
• Voltage Drop: < 1.5 VDC typical
• Current Ratings: 2 A per point; 10 A surge per 10 ms
• Load Leakage: 2 mA maximum
• Power Module Load: < 10 watts
• Isolation: 1,500 VDC minimum point-to-logic
• Common Mode Rejection: -85 dB (DC – 100 Hz)
• Input Overrange Protection: 150 VDC / 115 VAC continuous
• Diagnostic Indicators: ON/OFF state per point; PASS / FAULT / ACTIVE module status; LOAD/FUSE alarm
• Load Alarm — Stuck-ON: Detects stuck-ON point when all others are commanded OFF (de-energized)
• Load Alarm — Stuck-OFF: Detects stuck-OFF point when all others are commanded ON
• Configuration: Serial (recommended for de-energize-to-trip control programs)

Installation Guide

1. Install the 3674 into an I/O slot in the Tricon chassis.
2. Connect to a compatible commoned DO termination panel (e.g., 9662 series for 24 VDC outputs).
3. Wire 24 VDC field devices to the termination panel. Ensure total current draw per common group does not exceed module ratings.
4. Configure output forcing and fault responses in TriStation 1131.
5. Verify all outputs during commissioning using TriStation online monitoring. Test stuck-ON and stuck-OFF alarm functionality.

FAQ

Q: What is a "dual" output module?
A: A dual output module has two independent output circuits per point (or per group), providing higher availability than a single output but less than full TMR. It is suitable for applications where some redundancy is desired but full TMR is not required. The voltage-loopback circuit verifies switch operation independently of load presence.

Q: What is the difference between 3664 and 3674?
A: Both are 32-point dual digital output modules. The 3664 is the earlier version; the 3674 is the updated/revised version with enhanced diagnostics. Verify chassis and firmware compatibility when selecting between them.

Q: Can I use the 3674 for safety-critical outputs?
A: The 3674 is a dual (not TMR) module. For SIL-rated safety outputs, use TMR modules like 3604E (24 VDC, 16 points) or 3625 (supervised 24 VDC, 32 points). Use 3674 for non-safety or secondary control functions.

Selection Tips

• Choose 3674 for high-density 24 VDC digital outputs in non-safety-critical applications (e.g., status lamps, auxiliary relays, non-interlocked valves).
• For safety-critical DO, select TMR modules: 3604E (standard) or 3624/3625 (supervised).
• Verify total current capacity per common group to avoid overloading the module.
• Pair with 9662-830 or compatible 24 VDC DO termination panels.
• The 3674 is optimized for de-energize-to-trip control programs — verify your safety philosophy before selection.