Chapter 2
Description
12
Rockwell Automation Publication ICSTT-RM451D-EN-P - March 2021
The FIU receives isolated power from the HIU for logic. The FIU provides
additional power conditioning for the operational voltages that are required
by the FIU circuitry. An isolated 6.25 Mbit/sec serial link connects each FIU to
one of the HIU slices.
The FIU also measures a range of onboard “housekeeping” signals that help in
monitoring the performance and operating conditions of the Module. These
signals include power supply voltages, current consumption, onboard
reference voltages, and board temperature.
The HIU is the point of access to the Inter-Module Bus (IMB) for the Module.
It also provides power distribution and local programmable processing
power. The HIU is the only section of the I/O Module to directly connect to the
IMB Backplane. The HIU is common to most high integrity I/O types and has
type 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 help
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 IMB.
•
Galvanically isolated serial data interface to the FIU slices.
•
Redundant power sharing of dual 24V DC 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.
The Front Panel Unit (FPU) contains the necessary connectors, switches,
logic, and LED indicators for the Front Panel. For every type of Trusted I/O
Module, the FPU contains the Slice Healthy, Active/Standby, the Educated
LED indicators, and the Module removal switches. Additional bicolor LEDs
provide status indication for the individual I/O signals. Serial data interfaces
Host Interface Unit (HIU)
Front Panel Unit (FPU)
