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

dependent and product range common functions. Each HIU contains three

independent slices, commonly referred to as A, B, and C.

All interconnections between the three slices incorporate isolation to prevent

any fault interaction between the slices. Each slice is considered a Fault

Containment Region (FCR), as a fault on one slice has no effect on the

operation of the other slices.

The HIU provides the following services common to the modules in the

family:

• High Speed Fault Tolerant Communications with the TMR Processor

via the IMB interface.

• FCR Interconnect Bus between slices to vote incoming IMB data and

distribute outgoing I/O Module data to the IMB.

• Optically isolated serial data interface to the FIU slices.

• Redundant power sharing of dual 24 Vdc chassis supply voltage and

power regulation for logic power to HIU circuitry.

• Magnetically isolated power to the FIU slices.

• Serial data interface to the FPU for Module status LEDs.

• SmartSlot link between active and standby modules for coordination

during Module replacement.

• Digital Signal Processing to perform local data reduction and self

diagnostics.

• Local memory resources for storing Module operation, configuration,

and field I/O data.

• Onboard housekeeping, which monitors reference voltages, current

consumption and board temperature.