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.

Potential Safety Issue

Invensys has reviewed the issue described in this Product Alert Notice and determined that, if no action is taken to resolve the issues described in this notice, there is a potential risk of harm to people, property, and/or the environment. Third-party integrators and distributors of Triconex® systems need to notify their end-user customers of this issue. All end-users should immediately review and analyze the impact of this issue to their applications. If this issue is found to be applicable, remedial actions should be taken to ensure the continued safe operation of affected systems.

Subject: Possible Spurious Output Transitions on the Tricon 3625 24V Digital Output Modules  Affected Products

The following modules used in TriconTM system versions 10.2.0-10.2.5, 10.3.0-10.3.3, 10.4.0-10.4.3, and 10.5.0-10.5.2 are affected:

• Model 3625 24V Digital Output Module

• Model 3625A 24V Digital Output Module

• Model 3625N 24V Digital Output Module