Rockwell Automation T8448 Trusted TMR Zone Interface Module - 40 Channel - Manual (Page 10)

Trusted
TM
Module T8448
Issue 14 Apr 10 PD-T8448 10
Slice Power
Supply Housekeeping
Failsafe Bias Control A
Back Plane
Power Bus
1
Front Panel
T
M
R
In
te
rm
o
d
u
le
B
u
s
Opto Isolation Boundary
Serial Display Latches
Voted Status Display LEDs
Internal Voting Bus
Housekeeping
Module Temp
Supply Diag
DSP reference
Health
Indicators
Back Plane Power Bus 1
Back Plane Power Bus 2
Slice A
OFIU HIU
FPDU
FPIU
Field Logic
Control
Redundant Supply
N.C. N.O.
Diagnostic
Monitor
Bus
Interface
Bus
Interface
Slice Power
Supply Housekeeping
Failsafe Bias Control B
Field Logic
Control
N.C. N.O.
Diagnostic
Monitor
Slice Power
Supply Housekeeping
Failsafe Bias Control C
Field Logic
Control
N.C. N.O.
Diagnostic
Monitor
Bus
Interface
Front Panel
Voting Logic
Slice
Control
B Time Stamp
Slice
Control
B Time Stamp
Slice
Control
A Time Stamp
OFTU
+V
Slice B
Slice C
A B C
Group
Fail-Safe
Switch
-
V
Field Interface
Protection Circuit
Figure 2 shows a simplified block diagram of the Trusted TM Zone Interface Module.
Figure 2 Function Block Diagram
1.1. Field Termination Unit (FTU)
The Field Termination Unit (FTU) is the section of the I/O module that connects all three FIUs to a
single field interface. The FTU provides the Group Fail-safe switches and passive components
necessary for signal conditioning, over-voltage protection, and EMI/RFI filtering. When installed in a
Trusted
TM Controller or Expander Chassis, the FTU field connector interconnects to the Field I/O Cable
Assembly attached at the rear of the chassis.
The SmartSlot link is passed from the HIU to the field connections via the FTU. These signals go
directly to the field connector and maintain isolation from the I/O signals on the FTU. The SmartSlot
link is the intelligent connection between active and standby modules for co-ordination during module
replacement.
1.2. Field Interface Unit (FIU)
The Field Interface Unit (FIU) is the section of the module that contains the specific circuits necessary
to interface to the particular types of field I/O signals. Each module has three FIUs, one per slice. For
the TMR Zone Interface Module, the FIU contains one stage of the output switch structure, and A/D
monitoring circuits for each of the channels Two additional A/D circuits provide optional monitoring of
the external field I/O supply voltage.
The FIU receives isolated power from the HIU for logic. The FIU provides additional power
conditioning for the operational voltages required by the FIU circuitry. An isolated 6.25Mbit/sec serial
link connects each FIU to one of the HIU slices.
The FIU also measures a range of on-board “house-keeping” signals that assist in monitoring the
performance and operating conditions of the module. These signals include power supply voltages,
current consumption, on-board reference voltages, board temperature, and condensation.