Rockwell Automation T3468A ICS Regent DC Guarded Digital Output Modules - Manual (Page 7)

(T3461A, 62A, 68A) DC Guarded Digital Output Modules
P D - 6 0 1 9 M a r - 0 6
7
Blown Fuse Indicators
The red BLOWN FUSE indicators switch on when the
adjacent front panel fuse opens. If all four fuses in a group
have opened, all of the BLOWN FUSE indicators will switch
off and the condition will be annunciated by the module’s
FAULT indicator, which will be on.
Application
Guarded digital output modules provide a suitable interface to
safety-critical output devices. These safety-critical devices
typically include solenoids, actuators, or other process
interlock outputs. Guarded output modules can be used for
fail-safe or fault tolerant operation.
Fail-Safe Configuration
As shown in Figure 3, fail-safe configuration uses a single
Guarded module. In this configuration, the worst case failure
will cause the output to fail to the off state.
In a fail-safe configuration, removing the module disables all
outputs.
Figure 3. Fail-Safe Configuration.
Fault Tolerant Configuration
For fault tolerant operation, two Guarded modules are
connected in parallel as shown in Figure 4. In this
configuration, operation continues even if one module fails.