Rockwell Automation AADvance Controller Solutions Handbook - Manual (Page 114)

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7-20 Document: 553631
(ICSTT-RM447J_EN_P) Issue: 09:
Solutions Handbook (AADvance Controller)
T9451 Digital Output Module, 24V dc, 8 channel
The T9451 digital output module interfaces up to eight final
elements and can switch 1A at 32V dc for each device. It
features voltage and load current monitoring on each channel,
reverse current protection and short and open circuit line
monitoring. It is designed to always be able to switch off an
output when demanded. No single failure within the module can
cause a stuck-on failure. The module supports dual redundant
power feeds for field devices without the need for external
diodes.
The output module isolates the processor module from the
output channel control and data management circuits, thus
protecting the processor module from potential faults in the
output control circuits and field connections.
The output channel protection activates when the channel load
exceeds a safe limit. The reverse voltage protection circuit in
each output channel ensures that externally applied voltages do
not generate current flow into the module outputs.
The module has self-checking functionality. Short circuit and
open circuit line monitoring is provided on all outputs. Internal
diagnostics carry out ongoing functionality checks ensuring that
the output channel command data is correctly transferred to the
output. In addition, the processor module initiates a test
sequence on each output channel, checking for 'stuck-on' and
'stuck-off' conditions on the output switch pairs.
Front panel LEDs provide module, channel and field connection
status indications. These status indications can be connected to
application variables and viewed at the Workbench.
When a controller uses a pair of digital output modules in a dual configuration, the two
fail-safe output switches on each channel are combined in a parallel arrangement so
that they automatically form a fault-tolerant output configuration.