Tricon System Introduction

The Tricon is a state-of-the art controller that provides fault tolerance by means of Triple-Modular Redundant (TMR) architecture. TMR integrates three isolated, parallel control systems and extensive diagnostics in one control system. The system uses two-out-ofthree voting to provide high-integrity, error-free, uninterrupted process operation with no single point of failure.

The Tricon controller uses three identical channels. Each channel independently executes the control program in parallel with the other two channels. Specialized hardware/software voting mechanisms qualify and verify all digital inputs and outputs from the field, while analog inputs are subject to a mid-value selection process. Because each channel is isolated from the others, no single-point failure in any channel can pass to another. If a hardware failure does occur on one channel, the other channels override it. Meanwhile the faulting module can easily be removed and replaced while thecontroller is online without interrupting the process. Setting up control programs is simplified with the triplicated Tricon system, because it operates as a single control system from the user’s point of view. The user terminates sensors and actuators at a single wiring terminal andprograms the Tricon with one set of control program logic.

The Tricon controller manages the rest! Extensive diagnostics on each channel, module, and functional circuit immediately detect and report operational faults by means of indicators or alarms.

DIGITAL INPUT MODULES

The following types of digital input modules are available for SR use in NPPs:

• Model 3501TN2 (EDI 5909) is a 115 VAC/DC digital input module with 32 isolated input points. This model has standard diagnostics, but does not have the ability to verify the transition of a normally energized circuit to the off state. In addition to the Pass/Fault/Active indicator lights, this module has indicator lights showing if each of the 32 input points is on or off. The 3501TN2 is a surface mount version of the 3501TN approved for use on the Tricon V9 platform. The software has minor updates and was qualified with the Tricon V10 platform.

• Model 3502EN2 (EDI 5909) is a 48 VAC/DC digital input module with 32 inputs. Four groups of 8 inputs use a common reference point. Unlike the Model 3501TN2, this model can continuously verify the transition of a normally energized circuit to the off state. In addition to the Pass/Fault/Active indicator lights, this module has indicator lights showing if each of the 32 input points is on or off. The 3502EN2 is a surface mount version of the 3502EN approved for use on the Tricon V9 platform. The software has minor updates and was qualified with the Tricon V10 platform.

• Model 3503EN2 (EDI 5909) is a 24 VAC/DC digital input module with 32 inputs. Four groups of 8 inputs use a common reference point. Like the Model 3502EN2, this model can continuously verify the transition of a normally energized circuit to the off state. In addition to the Pass/Fault/Active indicator lights, this module has indicator lights showing if each of the 32 input points is on or off. The 3503EN2 is a surface mount version of 3503EN approved for use on the Tricon V9 platform. The software has minor updates and was qualified with the Tricon V10 platform.