I have a HMS-EN2SE-R linking device that is communicating with a device via modbus. Over Ethernet I would like to connect two separate (redundant) Controllogix processors to read the data in the linking device. I have the linking device connected to the first PLC and it works great, but when I add a connection on the second PLC, the HMS module in the Controllogix IO tree gives a Module Fault: “Connection Request Error: Module in Use” message. Is there a setting I need to change to allow communication to both processors? Or would I need to create duplicate bits in the HMS device so each PLC was reading different bits? Or is not possible at all to have two processors read from the same linking device? Any help would be appreciated, thanks!
Hello @nrr ,
The EN2SE-R is not designed to work in a redundant setup. One issue is the AOP configures Tags in the plc which makes the configuration a little more complicated. A check sum is used to keep the PLC module definition and the linking device config match.
I am not too familiar with how redundant PLC’s setup EIP communication but it seems like this is causing issues with the connection to the en2se-r. From the error it seems like the issue is from both PLC trying to make the same connection to the en2se-r. The AOP sets up an exclusive owner connection which as its name suggests, only one EIP scanner can use at a time.
You might be able to find some work around where you setup custom message instructions for the second plc to read data with. This would not be a copy on the AOP and would just me reading the IO from the EIP module. I am not sure how this would work with your redundant PLC setup. The CIP implementation is in the user guide if you would like to explore this options. See section F
I would recommend looking into using an (ABC3007) or (AB7072). These allow for more generic Ethernet IP IO connections to be setup. They still only allow one exclusive owner connection but I would expect it to be a little easier to setup a redundant connection and closer to how you would typically setup a redundant setup.