Triconex 3451S2 Solid‑State Relay Output Module (Tri‑GP RO 3451S2)
Product Introduction
The Triconex 3451S2 is a solid‑state relay output module (SRO module) for the Tri‑GP v2.x system. It is developed for non‑critical control points and designed for field devices incompatible with high‑end solid‑state output switches, widely applied for alarm panel interface connection.
Though not built on triple‑modular redundant hardware architecture, the Triconex 3451S2 receives output signals from three‑channel main processors and drives 32 independent solid‑state relay channels after 2‑out‑of‑3 voting logic. Each output channel is equipped with an I/O loop‑back circuit, which verifies relay actuation status independent of load conditions. Continuous on‑board diagnostics enable channel fault detection.
The Triconex 3451S2 supports hot‑standby and permits on‑line replacement of faulty modules. It features a mechanical keying latch to prevent mismatched baseplate installation. The Triconex 3451S2 must be installed and wired with the matching 2451S2 baseplate.
Technical Specifications
| Parameter | Value |
| Channel Count | 32 channels, two‑channel grouped common terminal |
| Nominal Voltage | ±24 VDC |
| Operating Voltage Range | ±30 VDC |
| Maximum Switching Peak Voltage | ±33 VDC |
| Max. Switching Power (Resistive Load) | 15 W |
| Maximum Off‑State Leakage Current | ＜100 μA |
| Nominal Max. Current per Channel | 0.5 A |
| Over‑current Threshold per Channel | 0.7 A |
| Baseplate Voltage Drop @ 0.5 A Operation | ＜0.25 V |
| Baseplate Fuse | One 0.75 A fast‑blow fuse per output channel |
| Functional‑to‑Earth Isolation | Min. 500 VDC |
| Functional‑to‑Logic Ground Isolation | Min. 800 VDC |
Core Advantages
- Three‑channel signal voting logic: Voting computation for signals from three processors mitigates false output risks induced by single‑channel anomalies, fully aligned with the Tri‑GP safety system framework.
- No‑load loop‑back diagnostics: Relay health for each channel can be tested without external field loads, identifying potential channel defects in advance and reducing commissioning & troubleshooting efforts.
- Hot‑standby on‑line replacement: Faulty modules can be swapped without cabinet shutdown. Other control points keep running to sustain continuous plant production.
- Grouped common‑terminal design: Two outputs share one common connection, reducing cabinet wiring work for multi‑point signals such as alarm indicators and audible‑visual alarm panels.
- Baseplate‑integrated independent fuses: Each output channel is protected by an individual fast‑blow fuse. Short‑circuit on one channel blows only its dedicated fuse instead of disabling the whole module.
Product Features
- The Triconex 3451S2 is a non‑TMR I/O module intended for non‑safety‑critical output points. It shall not be used for high‑risk interlock execution loops such as ESD emergency shutdown.
- Mechanical keying prevents insertion onto mismatched baseplates. All 32 solid‑state relay outputs are independently driven with channel‑to‑channel isolation protection.
- Automatic full‑channel diagnostics run during operation, and fault status is reported back to the Tri‑GP controller.
- Fully compatible with Tri‑GP v2.x hardware and bus‑interoperable with matched processors and communication modules.
- The 3451S2 cannot connect to field cables directly and requires the 2451S2 direct‑wiring baseplate.
Application Fields
- Petrochemical: Audible‑visual alarm panels, status indicators, field alarm horn driving outputs
- Power industry: Non‑safety interlock alarm points and local status indication for auxiliary equipment
- Coal chemical: Auxiliary unit alarm outputs and non‑critical process status indication
- Water treatment: Equipment alarm prompts and local status light signal outputs
- General process industry: Auxiliary alarm and panel indicator switch‑output scenarios excluding safety‑related shutdown functions
Product Comparison
| Model | 3451S2 | 3401S2 (TMR Digital Output) |
| Hardware Architecture | Non‑TMR SRO solid‑state relay output | Full TMR triple‑modular redundant output |
| Target Points | Non‑critical alarms & status indication | SIL‑rated safety interlock & ESD execution outputs |
| Channel Configuration | 32 channels, two‑point grouped common terminal | 32 channels, grouped common terminal |
| Hot‑swap Support | Hot‑standby on‑line replacement | TMR hot‑swap capable |
| Typical Matching Baseplate | 2451S2 | 2401S2 |
| Application Trade‑off | Cost‑optimized; for non‑safety loops only | High safety integrity; for critical execution loops with higher procurement cost |
Selection Note: Do not deploy Triconex 3451S2 for safety interlock shutdown loops; select TMR triple‑redundant output modules instead. Use 3451S2 for alarm and panel‑indication circuits to optimize overall project hardware expenditure.
Associated Components
- Main Module: 3451S2 Solid‑State Relay Output Module
- Matching Baseplate: 2451S2 Solid‑State Relay Output Direct‑Wiring Baseplate
- System Main Processor: 3101S2 Tri‑GP Processor Module
- I/O Interconnection: 2921 I/O Interconnect Assembly
- Slot Protection Accessories: 2900 Slot Cover, 2901 Terminal Protector
Recommended Triconex Part Numbers
3101S2 Processor Module,
3301S2 Digital Input Module,
3351S2 Analog Input Module,
3361S2 Mixed Analog‑Digital Input Module,
3381S2 Pulse Input Module,
3401S2 TMR Digital Output Module,
3481S2 Analog Output Module,
3482S2 High‑Current Analog Output Module,
2301S2 Digital Input Baseplate,
2351S2 Analog Input Baseplate,
2401S2 Digital Output Baseplate,
2451S2 Solid‑State Relay Output Baseplate,
3201S2 Tri‑GP Communication Module,
8311 Tri‑GP System 24 VDC Power Supply Module,
2921 I/O Interconnect Assembly
Important Notices
- Verify controller firmware revision prior to installation. Tri‑GP v2.x is required; 3451S2 is incompatible with older hardware revisions.
- Strictly observe application boundaries. Never deploy Triconex 3451S2 in high‑risk safety‑interlock loops. Restrict usage to non‑critical alarm and status‑indication circuits.
- Field‑load current and power must stay below module technical limits to avoid frequent baseplate fuse failure.
- Apply only signals of identical voltage rating to each common group on the 2451S2 baseplate. Mixed‑voltage connection to one common group is forbidden.
- Protect baseplate fuses during cabinet maintenance. Replacement fuses must be 0.75 A fast‑blow type.
- Respect mechanical keying features. Forced insertion of 3451S2 onto unmatched I/O baseplates may result in hardware damage.
FAQ
Q: Can the 3451S2 drive ESD emergency shutdown valve outputs?
A: No. The 3451S2 is a non‑TMR SRO module designed exclusively for non‑critical alarm‑indication points. TMR triple‑redundant output modules shall be adopted for safety‑interlock loads such as ESD shutdown valves.
Q: Must the 3451S2 and 2451S2 be purchased and used as a set?
A: Yes. The 3451S2 module cannot terminate field wiring directly. The 2451S2 is its dedicated keyed direct‑wiring baseplate and is mandatory for wiring and installation.
Q: Does the 3451S2 support channel self‑test without connected loads?
A: Yes. Built‑in I/O loop‑back circuitry enables independent relay‑channel health checking by the system without external field loads.
Q: What is the maximum load per channel of the 3451S2?
A: Nominal 0.5 A per channel; short‑term over‑current limit 0.7 A; maximum resistive‑load power 15 W. Load current and power shall not exceed rated values to prevent repeated baseplate fuse blow‑out.
Q: Can 3451S2 work with legacy Tri‑GP v1.x systems?
A: The 3451S2 is compatible only with Tri‑GP v2.x controller hardware. v1.x hardware features incompatible bus logic and cannot accept this module.
Q: Will on‑line hot‑swap cause all remaining output channels to drop out?
A: No. Under hot‑standby mode, replacement of a faulty 3451S2 only affects its own 32 channels. I/O channels on other slots maintain normal output.
Q: Is full‑module replacement required after channel fuse burnout?
A: Fuses are located on the 2451S2 baseplate. Only the corresponding fast‑blow fuse on the baseplate needs replacement; the 3451S2 module itself can remain in service.
Q: For two‑point grouped common terminals, can different voltage levels share one common group?
A: Two outputs within one group share a common return path. Only signals of identical voltage level can be applied to the same group. Mixed‑voltage signals on one common group are prohibited.
