I am having problems connecting to a Modbus TCP slave

[MillieG1996]

Hello everyone

I am hoping someone here can help me out. I’m not too clued up on automation but I have learned a bit with this project.

I would like to use a Revolution PI Connect as a modbus master to send data to the cloud. I am connecting to a bit of equipment that has multiple devices and i have the modbus register for it all. All of these bits of equipment are on a remote site which i can connect to through a PC. The PC, RevPI, and modbus slave are all on the same network. I can ping and connect to the slaves HMI via the URL on the PC however when i try and connect via modbus, i am refused. When SSH’d into the PI, i try to connect via ‘nc -zv 192.168.#.### 502’ and i get the message ‘connection refused’. I have also tried connecting via modscan on the PC after setting an inbound rule for port 502 and it fails with a message ‘connection terminated’.

Is this a problem with the slave and the modbus not being set up correctly or are there any more troubleshooting steps to try?

Thanks for any help in advance.