CIP Error - CIP Extended Status: 0x311 with the EtherNet/IP driver

Updated Jan 9, 2019

Reported In


  • NI-Industrial Communications for Ethernet/IP

Issue Details

When I communicate with a PLC using NI-Industrial Communications for Ethernet/IP, I get the following error:

Error -251723760 
Details: CIP Error - Extended status may be available
CIP Status: 0x1 (Connection failure)
CIP Extended Status: 0x311 (Port not available)

Why do I receive this error?


If you mistakenly swapped the backplane port number and Logix slot number, you will get this CIP Error. The syntax for a simple system is <PLC address>,<backplane port number>,<Logix slot number>.

Example:,1,0 is the routing path for a ControlLogix 5561 with IP address and with the processor in slot 0 of an AB-1756 4-slot backplane.

Additional Information

This error message is not to be confused with a TCP/IP port.  It actually relates to the slot configuration as specified in the network path parameter for an EIP Tag Read/Write VI terminal.