IX30 IO over Modbus TCP

Cellular Routers
1

I am trying to read the integrated IO values from an IX30 over Modbus TCP from either the Eth2 port or remotely via a Cellular VPN link using a Modbus TCP Client.

I have enabled the Modbus gateway as per the manual for a socket connection ( setup below) but when trying to connect locally via Eth 2 I get a 0x0A - GATEWAY PATH UNAVAILABLE response error.

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The Status page shows a connection but failing.

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Debugging info.

Nov 25 03:25:54 Digi IX20 config: (service.modbus_gateway.debug) changing from (false) to (true)
Nov 25 03:25:55 Digi IX20 modbus: loaded 1 server configs
Nov 25 03:25:55 Digi IX20 modbus: loaded 0 client configs
Nov 25 03:25:55 Digi IX20 modbus: apply_client_configurations
Nov 25 03:25:55 Digi IX20 modbus: apply_server_configurations
Nov 25 03:25:55 Digi IX20 modbus: socket_add_listening_socket: 0.0.0.0:502
Nov 25 03:25:57 Digi IX20 modbus: Connected to ubus
Nov 25 03:26:04 Digi IX20 modbus: new_incoming_connection_cb fd 7 events 0x1
Nov 25 03:26:04 Digi IX20 modbus: server_context_enqueue
Nov 25 03:26:04 Digi IX20 modbus: New connection
Nov 25 03:26:04 Digi IX20 modbus: server_socket_handle_socket_connected
Nov 25 03:26:04 Digi IX20 modbus: start_server_socket_inactivity_timer: 60 seconds
Nov 25 03:26:04 Digi IX20 modbus: start_socket_inactivity_timer: 60 seconds
Nov 25 03:26:04 Digi IX20 modbus: start_server_socket_inactivity_timer: 60 seconds
Nov 25 03:26:04 Digi IX20 modbus: start_socket_inactivity_timer: 60 seconds
Nov 25 03:26:04 Digi IX20 modbus: no client found for address: 1
Nov 25 03:26:04 Digi IX20 modbus: creating exception a
Nov 25 03:26:04 Digi IX20 modbus: sending exception type 0xa to serial

So it looks like the DIGI is being a Modbus Gateway for a connected client only, if this is the case then is there some way of creating an internal client which allows access to the IO?

Or are there some other settings I am missing? Possibly an application manual for reading the inbuilt IO?

Any help appreciated.

cheers

Tim.

2

@0sm0 you’ve run into the same thing we did. It seems the IX30 has physical IO, and a Modbus Gateway, but there’s no link between them.

We ended up writing a python script which utilizes pyModbusTCP and ran it on the IX30. I am not near the IX30 right now to pull the config, but if memory serves, you can pull the values from the physical IO, dump it into registers, then I think we had a custom firewall rule to expose port 502 for the purpose. We disabled the on-board modbus gateway.

https://pymodbustcp.readthedocs.io/en/latest/

I will be back at the office after the weekend and may be able to pull more info if needed. Hopefully this gets you moving in the right direction.

3

Thanks dgici,

Thought as much. Will have a look into the pyModbusTCP script.

Any help appreciated.

Cheers

Tim.