"Connection Request Error: Bad Class" in Studio 5000

I have the following components:

  • Allen Bradley Compact Logix PLC (1769-L19ER-BB1B)
  • Anybus X-gateway (AB7669-F)
  • Modbus server running on a PC

I am attempting to connect to the Modbus server from the PLC through the gateway. I am getting the error “(Code 16#0005) Connection Request Error: Bad Class” in Studio 5000 when I bring the PLC online.

I have configured the gateway as follows using the Anybus Configuration Manager:

I have the following Module Definition for the gateway in Studio 5000:

The PLC is at IP I have configured both sets of dip switches on the gateway to be (I am unsure if these dip switches should be set to the same address, or if they should differ).

The Anybus web portal appears so:

I have tried tweaking the configurations every which way using the tools shown- is it possible there is another tool I need that I am unaware of?

Hello @Austin,

Can you provide a bit more detail about what devices you are expecting to be the masters in this setup? I fear you might have the opposite device then you are expecting. looking at the images provided it looks like you have it setup to try and read and write from our Ethernet/IP scanner. If you want to read data from a modbus TCP server you would want the X-gateway to be a modus TCP client/master and then the ethernet/IP side to be an ethernet/IP adapter/slave. This would allow your PLC to read data from the gateway. If this is the case the ab9006 should be the correct device. I would recommend reaching out to the inside sales team to verify. (312-829-0601 or us-sales@hms.se)


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I want the PLC to be the master, and the Modbus TCP device to be the slave.

The gateway product title is “EtherNet/IP Scanner - Modbus TCP Server.” I had assumed that meant “connects an EtherNet/IP Scanner to a Modbus TCP Server.” I understand now that it actually is referring to the roles the gateway fulfills.

Thank you for your assistance!

You are correct the name corresponds to the role the x-gateway has.

Happy new year!