Rockwell Automation Publication 2080-UM002N-EN-E - November 2022 147
Chapter 8          EtherNet/IP Network
The UDFBs also appear in the (User defined) tab in the ladder logic toolbox.
Connection Fault Codes The following table lists the possible connection faults that can occur and the corrective 
actions that you can take to resolve the fault.
UDFBs for Kinetix 5100 Drives
UDFBs for PowerFlex 520-series Drives
Table 25 - List of Connection Fault Codes
Fault Code Display Text Fault Corrective Action
0x0001 Connection failure. A connection to a module failed.
Extended status codes in these ranges provide more detail 
as to the connection failure.
0x0002 Resource unavailable.
Possible causes include the following:
• There are not enough connections available either for the 
controller or for the communication module being used to 
connect through.
• The I/O module that is targeted does not have enough 
connections available.
• Check the connection use of the controller or 
communication module. If all connections are used, try to 
free some of the used connections or add another module 
to route the errant connection through.
• Check the number of controllers making a connection to 
this I/O module and verify that the number of connections 
is within the limits of the I/O module.
0x0003
Invalid value in an object 
specific data parameter of a 
service request.
A parameter that is associated with the request was invalid.
Possible causes include the following:
• The module in use (that is, the physical module) is 
different than the module specified in the I/O 
configuration tree and is therefore causing the 
connection or service to fail.
• The fault may occur even when the module passes the 
electronic keying test. This may result when Disable 
Keying or Compatible Keying options were used in the 
module configuration instead of the Exact Match option.
• Despite passing the electronic keying test, the module 
being connected to does not have the same features or 
settings as the module specified in the I/O configuration 
tree and does not support the connection or service being 
attempted.
Check the module in use and verify that it exactly matches 
the module that is specified in the application. For more 
information about electronic keying, see the user manual 
for the module you are using.
0x0004
Connection Request Error:
Bad Segment.
IOI segment error on connection request.
The target module does not like one of the parameters in 
the connection request. This may occur if improper module 
keying is being used or if the wrong map type attribute is 
set in the map entry.
0x0005
Connection Request Error:
Bad Class.
The controller is attempting to make a connection to the 
module and has received an error.
Possible causes include the following:
• The configured address for the connection to the module 
is incorrect.
• The module in use (that is, the physical module) is 
different than the module specified in the I/O 
configuration tree and is therefore causing the 
connection or service to fail.
• The fault may occur even when the module passes the 
electronic keying test. This may result when Disable 
Keying or Compatible Keying options were used in the 
module configuration instead of the Exact Match option.
• Despite passing the electronic keying test, the module 
being connected to does not have the same features or 
settings as the module specified in the I/O configuration 
tree and does not support the connection or service being 
attempted.
• Check the module in use and verify that it exactly 
matches the module that is specified in the application. 
For more information about electronic keying, see the 
user manual for the module you are using.
• If you are using a 1756-DHRIO module, verify that the 
Channel type selected in the software (DH+™ or remote 
I/O network) matches the module's rotary switch settings.