ICS TRIPLEX T8403 Trusted TMR 24 Vdc Digital Input Module 40 Channel 

 Product Details:

The Trusted TMR Processor is a fault tolerant design based on a Triple Modular Redundant (TMR) architecture operating in a lock-step configuration. 
Figure 1 shows, in simplified terms, the basic structure of the Trusted TMR Processor module.

The module contains three Processor fault containment regions (FCR), each containing a Motorola Power PC series Processor and its associated memory (EPROM, DRAM, Flash ROM,
and NVRAM), memory mapped I/O, voter and glue logic circuits. 
Each Processor FCR has voted two-out-of-three (2oo3) read access to the other two Processor’s FCR memory systems to eliminate divergent operation.

The module’s three Processors store and execute the application program, scan and update the I/O modules and detect system faults. 
Each Processor executes the application program independently, but in lock-step synchronisation with the other two. 
Should one of the Processors diverge, additional mechanisms allow the failed Processor to re-synchronise with the other two.

Each Processor has an interface which consists of an input voter, discrepancy detector logic, memory, and an output driver bus interface to the Inter-Module Bus. 
The output of each Processor is connected by the module connector to a different channel of the triplicated Inter-Module Bus.