Triconex 3504E Digital Input Module with 72 VDC Maximum Voltage and Triple-Isolated Channels

Each 64-point digital input (DI) module features three isolated channels, with a microprocessor on each channel that scans input points, compiles data, and transmits it to the main processors on demand. Input data is then voted at the main processors just before processing to ensure the highest integrity.

All digital input modules run continuous diagnostics for each channel. A fault on any channel triggers the module Fault indicator and the chassis alarm, while the module continues to operate properly with a single fault and often with certain types of multiple faults. Modules support hot-spare capability and require a separate External Termination Panel (ETP) to interface with the Tricon backplane. Mechanical keying prevents incorrect installation.

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

Each channel independently executes the control program in parallel with the other two, while specialized hardware/software voting mechanisms qualify and verify all digital inputs and outputs. Analog inputs are processed using a mid-value selection method. Because each channel is isolated, a failure in one channel cannot propagate to the others, and the faulty module can be removed and replaced online without interrupting the process.

Setting up control programs is simplified because the triplicated Tricon system operates as a single control system from the user's perspective. Sensors and actuators are terminated at a single wiring terminal, and the control program is written once. The Tricon controller handles all the voting and channel management internally.