TRICONEX DI3361 Input/Output Modules

The TRICONEX DI3361 is a high-density digital input module designed for use in the Tricon Safety Instrumented System (SIS). Its core function is to safely and reliably read discrete signals (such as those from pushbuttons, switches, relay contacts, proximity switches, etc.) from field devices into the Tricon controller for processing.

• Module Type: Digital Input Module

• System Platform: Belongs to the Triconex Tricon V9/V10 system or Tricon CX platform (depending on the specific version).

• Safety Level: Designed to meet the SIL 3 (IEC 61508/61511) Safety Integrity Level, serving as the cornerstone for safety-critical applications in the process industry.

• Primary Role: Monitors the "on/off" or "yes/no" status of field devices, such as:

• Emergency stop button status

• Alarm status of level switches

• Position feedback of valves (fully open/fully closed)

• Run/stop status of motors

• Pressure switch contacts

• Triple Modular Redundancy (TMR): The core of the Tricon system. Each DI3361 module actually contains three independent input channel circuits with identical functions. Three separate processors read these three signal paths respectively, perform voting, and determine the final status using a "2-out-of-3" (2oo3) mechanism. This ensures that even if one channel fails, the system can still obtain the correct signal and continue to operate safely.

• High Density: The DI3361 provides 32 digital input points, delivering robust I/O processing capability within limited rack space.

• Dry Contact Input: The module is designed to receive "dry contact" signals—passive contacts from field devices (e.g., mechanical switches, relay outputs). The module itself supplies an interrogation voltage (typically 24V DC or 48V DC, powered by an external power source) to the field contacts, then detects whether the contacts are open or closed.

• Field Wiring: Connected to field cables via a Field Termination Assembly (FTA), such as the 4352B or similar models. The FTA includes fuses, diagnostic LEDs, and terminal blocks, providing signal conditioning and protecting the main module.

• Diagnostic Function: The module features robust internal diagnostics, capable of detecting internal module faults (e.g., processor failure, communication failure), field power loss, and short circuits/open circuits in field wiring. It reports these fault conditions to the main controller.

• Hot Swappable: Supports module installation or removal without powering down the system, greatly facilitating maintenance and replacement while minimizing system downtime.

1. Field Signal: The contacts of field devices (e.g., switches) open or close.

2. Signal Detection: Three independent circuits inside the DI3361 module detect the status of these contacts separately.

3. Internal Voting: The three input processors send their respective readings to the main TriStation logic processor for voting.

4. Result Output: A "2-out-of-3" voting mechanism is used to generate a definitive status value (1 or 0).

5. Logic Processing: The main controller uses this voted, high-reliability signal to execute user-programmed safety logic (e.g., triggering a shutdown sequence if the emergency stop button is pressed).

6. Diagnostics: Continuous internal diagnostics run throughout the process; any faults are flagged and trigger alarms in the control system.

• Oil and Gas (offshore platforms, refineries, pipelines)

• Chemical and Petrochemical

• Power Plants (thermal power, nuclear power)

• Pharmaceutical Industry

• Other fields requiring high-reliability shutdown systems