Allen-Bradley 1756 Series, User Manual, Page: 111 / 136

Rockwell Automation Publication 1756-UM013B-EN-P - October 2019 111
Troubleshoot Your Module Appendix A
InternalFault Triggered on
the Safety Output Module
Table 3 describes conditions that can trigger InternalFault.
When the conditions that trigger the diagnostics as described in Table 3 are
corrected, the output faults are cleared, the tags and diagnostics reset to 0, and the
I/O status indicators turn off.
Table 3 - Conditions That Trigger InternalFault
Conditions Output
Behavior Tag Value Diagnostic Value I/O Status
Indicator
State
• Output Mode - BIpolar
• Point Operation Type -
Single
• Point Mode - Safety
• A load is connected
between a sourcing output
point and a sinking output
point.
• O.Ptxx.Data tag = 0
• An overload resistor shorts
the sourcing output point
to 0V DC
Faults I.Ptxx.Fault tag = 1 InternalFault = 1
The I/O
status
indicator for
the faulted
output point
is steady red.
• Output Mode - Bipolar
• Point Operation Type -
Single
• Point Mode - Safety or
Safety Pulse Test
• A load is connected
between a sourcing output
point and a sinking output
point.
• O.Ptxx.Data tag = 0
• Either output point shorts
to 0V DC
Faults I.Ptxx.Fault tag = 1 InternalFault = 1
• Output Mode - Sourcing
• Point Operation Type -
Single
• Point Mode - Safety or
Safety Pulse Test
• O.Ptxx.Data tag = 1
• Output point shorts to
24V DC
Faults I.Ptxx.Fault tag = 1
IMPORTANT : The tag
value occurs on the
faulted output point
and all of its associated
group points.
InternalFault = 1
IMPORTANT : The
diagnostic value occurs
on the faulted output
point and all of its
associated group
points.