8305A Main Processor CPU Module TRICONEX 8305A

The  is the core computing brain of the Congee Tricon TMR Safety Instrumented System (SIS), belonging to the Enhanced Unified Main Processor (UMP) category. The entire unit adopts a triple-redundant TMR (2oo3 voting) architecture, meeting SIL3 safety level, and is used in critical safety control scenarios such as ESD emergency shutdown, F&G fire and gas, BMS combustion management, and unit ITCC.

I. Triple Redundant TMR Fault-Tolerant Computational Core Functions (Most Core)

Three-Channel Synchronous Parallel Computation

Three units within the rack operate independently and synchronously. Each CPU independently reads field I/O signals and executes safety logic programs independently; all computational data is exchanged in real time between the three channels via a dedicated redundant TriBus bus, ensuring full clock synchronization, program synchronization, and data synchronization.​

Hardware 2003 Fault-Tolerant Voting

Input, operation, and output are all handled by a 3-out-of-2 hardware voting system: If any CPU channel fails, or there is a memory/clock/operation error, the other two normal channels automatically generate valid control outputs; the system continues to operate without disturbance even if a single channel fails, achieving 3-2-1 degraded operation and completely eliminating the risk of single-point failure shutdown.

Automatic Fault Channel Isolation

Once a hardware anomaly is detected in a single module, the faulty channel is automatically isolated, while the remaining two channels maintain 2002 fault-tolerant operation. Field control outputs are not interrupted, and online hot-swappable replacement of faulty modules is supported without shutdown.

II. Safety Control Logic Execution Function

Safety Program Storage and Real-Time Operation

Onboard large-capacity Flash memory stores safety control programs written in TriStation 1131 (ESD interlocking, unit speed regulation, combustion logic, ignition timing, etc.); a high-speed 32-bit processor performs real-time cyclic scanning of the logic, completing interlocking judgment, PID adjustment, timing control, and logic algorithm operations.

I/O Bus Data Scheduling and Management

Manage all DI/DO/AI/AO modules in the rack uniformly through a backplane fault-tolerant I/O bus:

Periodically acquire all field instrument, valve position, temperature, and pressure signals;

Send the final control command after voting to the output modules to drive solenoid valves, shut-off valves, and unit actuators;

Supports local rack + remote expansion I/O, compatible with up to hundreds of I/O cards, with a remote I/O transmission distance of up to 12km.

Process Safety Interlock Output

Executes plant-wide safety interlock logic: over-temperature/over-pressure/over-speed triggers emergency shutdown, flame loss interlocks fuel cut-off, and flame detection triggers valve closure and ventilation. All interlock actions are based on triple redundancy voting to prevent false trips/failures.

III. Comprehensive Online Self-Diagnosis Function (Safety Critical)

The module continuously performs self-checks, covering faults across the entire system and its own components, with real-time fault reporting and alarms:

Module Local Hardware Diagnosis

Full-cycle self-testing of CPU core, dual power supply, clock crystal oscillator, RAM, Flash program storage, TriBus synchronization bus, and backplane interface; immediately marking faulty channels upon detection of memory corruption, clock drift, or power supply drops.

Cross-Channel Synchronization Diagnosis

Real-time comparison of calculation results, program version, and synchronization clock of three modules to identify single-channel calculation drift, program inconsistency, and synchronization loss faults.

I/O Link and Field Loop Diagnosis

Collaborative I/O module detection of card faults, FTA terminal board disconnections, field instrument short circuits/open circuits, and actuator feedback anomalies, distinguishing between module faults and field instrument faults.

Status Indication and Fault Reporting

The panel LEDs display the running, fault, and primary/standby status; fault information is uploaded to the system operator station and historical event log, recording the fault channel, fault type, and occurrence time for easy maintenance.

IV. Multi-level Communication Management Functions

The coordinates all internal and external communication within the system, featuring multiple built-in hardware communication interfaces:

Internal TriBus Triple Redundancy Synchronous Bus

A dedicated high-speed synchronous bus between the three CPUs ensures real-time data exchange across the three channels, forming the communication foundation for TMR redundancy.

System External Industrial Communication

Dual Ethernet: Modbus TCP, OPC UA, for interfacing with DCS, supervisory control, and remote operator stations;

RS232/RS485 Serial Port: Modbus RTU, for connecting to third-party instruments, vibration monitoring, and unit PLC;

Supporting Expansion Communication Module Interface: Supports Tricon Peer network for interlocking interaction between multiple Tricon controllers;

Debugging and Configuration Communication

Local debugging serial port/USB, connecting to TriStation supervisory control software for program downloading, online monitoring, logic enforcement, and fault diagnosis reading.

V. Data Storage, Event and Logging Functions

Program and Parameter Permanent Storage

Flash permanently stores control programs, interlock values, and unit PID parameters, ensuring data retention even after power failure; RAM is used for real-time calculations and process caching.

Safety Event SOE Sequential Event Logging

Millisecond-level capture of interlock triggers, alarms, faults, and operational actions, stored in the processor, and can be uploaded to the supervisory control for accident tracing and analysis.

Real-time Process Data Caching

Caches real-time values of analog and digital signals from the field for upper-level reading and trend curve display.

VI. Operation, Maintenance, and Expansion Support Functions

Online Hot-Swap Maintenance

In case of a single unit failure, the can be hot-swapped for replacement, while the remaining two CPUs continue to operate with 2002 fault tolerance, eliminating the need for production shutdown.

System Expansion Support

Modular rack architecture; the can be expanded to multiple racks with local I/O and remote redundant I/O racks, adapting to large-scale SIS systems in chemical plants, power plants, and long-distance oil and gas pipelines.

Wide Industrial Environment Adaptability

Wide operating temperature range and resistant to electromagnetic interference, adaptable to highly interference-prone industrial cabinet environments such as refining, gas, and power plants, meeting the requirements of explosion-proof control systems.

Typical Application Scenarios

ESD Emergency Shutdown System, F&G Flame Detection and Control System

Compressor/Turbine ITCC Unit Integrated Control

Boiler and Heating Furnace BMS Combustion Management System

Oil and Gas Wellhead and Long-Distance Pipeline Safety Interlock System
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