Allen-Bradley 1756 Series, User Manual, Page: 69 / 136

Rockwell Automation Publication 1756-UM013B-EN-P - October 2019 69
1756-OBV8S Output Module Features Chapter 4
Other Conditions That Can Trigger the Short Circuit
Diagnostic on the 1756-OBV8S Module
Table 20 describes conditions that can trigger the Short Circuit diagnostic.
When the conditions that trigger the diagnostics as described in Table 20 are
corrected, the results are the same as described in Table 19 on page 68 .
Table 20 - Conditions That Trigger Short Circuit Diagnostic
Conditions Output Behavior Tag and Diagnostic Combinations I/O Status Indicator State
• Output Mode - Sourcing
• Point Operation Type - Single
• Point Mode - Safety Pulse Test
• O.Ptxx.Data tag = 1
• Output point is
shorted to 24V DC.
• Faults
• Turns off
• I.Ptxx.ShortCircuit tag = 1
• Short Circuit diagnostic = 1
• I.Ptxx.Fault tag = 1
or
• I.Ptxx.Fault tag = 1
• Internal Fault diagnostic = 1
IMPORTANT : The tag and diagnostic combinations that are
described occur on the faulted output point and all of its
associated group points.
The I/O status indicator for
the faulted output point
turns off.
These conditions exist on a pair of module outputs:
• Output Mode - Sourcing
• Point Operation Type - Dual
• Point Mode - Safety Pulse Test
• O.Ptxx.Data tag = 1 (Either output point in the pair)
• Output point is
shorted to 24V DC (Either output
point in the pair) .
• Faults
• Turns off
• I.Ptxx.ShortCircuit tag = 1
• I.Ptxx.Fault tag = 1
• Short Circuit diagnostic = 1
• Internal Fault diagnostic = 1
or
• I.Ptxx.Fault tag = 1
• Internal Fault diagnostic = 1
IMPORTANT : The tag and diagnostic combinations that are
described occur on the faulted output point and all of its
associated group points.
These conditions exist on a pair of module outputs:
• Output Mode - Sourcing
• Point Operation Type - Dual
• O.Ptxx.Data tag = 1 (Both output points in the pair)
• Output points are
shorted to each other.
• Faults
• Turns off
• I.Ptxx.ShortCircuit tag = 1 (Both output points in the
pair)
• Short Circuit diagnostic = 1 (Both output points in the
pair)
• I.Ptxx.Fault tag = 1
or
• I.Ptxx.Fault tag = 1 (Faulted output point and all of its
associated group points)
• Internal Fault diagnostic = 1 (Faulted output point and all
of its associated group points