750-8000 Modbus TCP Issue to 750-362

CODESYS
1

I am having an issue getting the 750-8000 basic controller to talk to a modbus fieldbus coupler 750-362. I have used modbus software on my pc and confirmed I can talk to the coupler. I wiresharked the controller and it doesnt even attempt to send out a modbus request. That status of the TCP slave says that it is “running” in codesys 3.5 but that the status is “connecting”. The log shows that I have a Socket_Recv() error and sometimes reports an error 6. I have tried it with a brand new project too with exactly the same issue. IP addresses are 192.168.1.0 for the controller and 192.168.1.1 for the coupler with a subnet mask of 255.255.255.0 I even tried a gateway of 192.168.1.10 through a couple wago 758-918 gateways. it definitely looks like its the controller thats the issue here. any help would be greatly appreciated. I have tested the fieldbus coupler with another PFC200 that I have and it works fine. There is some issue with the modbus tcp on the Basic Controller.

2

Change the IP address of the 750-8000 to something like 192.168.1.2 instead of 192.168.1.0.

192.168.1.0 is not typically a valid IP address for a network device because it is reserved as the network address in the 192.168.1.0/24 subnet.

Make sure to change the address of the MODBUS master in CODESYS too. It should work then.

2 Likes
3

Hey John,

Thanks! This worked perfectly!
I can’t believe I spent so much time on this.

Very much appreciated.

Adam Kosick