Rockwell Automation T8461 Trusted TMR 24/48V dc Digital Output Module User Manual
Sds-8461, Trusted, Industrial control system trusted
 
SDS-8461
Trusted
TM
Industrial Control System
Trusted
TM
TMR 24/48V dc Digital Output Module-T8461
Issue 8 Sep 2006
FRONT PANEL
DESCRIPTION
 
The Trusted
TM
TMR 24/48V dc Digital
Output module interfaces to 40 field 
output devices. Outputs are arranged 
in five groups of eight. All outputs in 
a group share a common power 
source and return. Fault tolerance is 
achieved through Triple Modular 
Redundancy (TMR) within the same 
module for each of the 40 output 
channels. 
The module provides on-board 
Sequence of Events (SOE) reporting 
with a resolution of 1ms. The “event” 
is the actual sensing of the field 
device loop current. 
 
Each triplicated section (slice) of the 
module, receives output instructions 
from the Trusted
TM
TMR Processor
and sends its data to an internal 
safety layer hardware voter. Each 
slice uses the voted data to control 
the outputs. Every output channel 
consists of a six-element voted array. 
The output switch array provides 
fault tolerant, uninterrupted control 
under an output switch failure 
condition. Output switching and fault 
diagnostics 
comply
with
the
demanding requirements of IEC-
61508 SIL-3 for First Fault - Fault 
Tolerant, and Second Fault - Fail 
Safe outputs. 
When a module fault is detected, the 
Trusted
TM
TMR Processor will flag the
unhealthy condition, indicating the 
need to replace the module. Control 
continues 
until
a
replacement
(healthy)
module
is
available.
Replacement modules can be located 
in a standby slot next to the module 
or in a designated SmartSlot with a 
temporary connection to the same 
Trusted
TM
Termination Assembly.
Each output is user configurable to 
perform line monitoring of the 
connected field devices to detect field 
wiring and load failures. Automatic 
over-current protection is inherent in 
every output circuit which eliminates 
the need for fuses. 
Modules may be placed in any I/O 
module slot in a Trusted
TM
Processor
Chassis or Expander chassis. Once 
the I/O module configuration is set, 
mechanical keying is available on all 
I/O modules to prevent inserting a 
module into an incorrect slot. 
Configuration of the module is carried 
out using the Trusted
TM
Toolset
running
on
an
Engineering
Workstation. Once configured and 
loaded into the Trusted
TM
Controller,
replacement modules are on-line 
educated by the TMR Processor. 
 
FEATURES 
40 TMR output channels per 
module 
Five isolated groups of eight 
outputs each 
Six-element voted output array
Comprehensive diagnostics 
and self-test 
First fault – Fault Tolerant, 
Second fault – Fail Safe 
Line monitoring on a per 
channel basis 
Automatic over-current 
protection – no fuses required 
2500V dc Opto-Isolation
Hot replaceable
Front panel status LEDs for 
each channel 
Module fault and status 
indicators 
IEC 61508, SIL 3 safety 
applications 
On-board 1ms resolution 
Sequence of Events reporting 
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