Connection through VPN error

[feltduck]

Hi, I’m trying to connect to my Raspberry Pi through VPN and in response I’m getting “Communication error”. I tried this before in local and it went well, all of this with a ModBus server installed on the Pi.

This is the line log
2023-03-06 12:36:25 Establish a TCP connection with 10.79.253.197:502

2023-03-06 12:36:26 Communication session with the Device 10 “Prueba”, type: KpModbus, address: 10, call number: 10.79.253.197
Request element group
Send (12): 01 1B 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!
Request element group
Send (12): 01 1C 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!
Request element group
Send (12): 01 1D 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!

2023-03-06 12:36:29 Disconnect from 10.79.253.197

2023-03-06 12:36:29 Establish a TCP connection with 10.79.253.197:502

2023-03-06 12:36:30 Communication session with the Device 10 “Prueba”, type: KpModbus, address: 10, call number: 10.79.253.197
Request element group
Send (12): 01 1E 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!
Request element group
Send (12): 01 1F 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!
Request element group
Send (12): 01 20 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!

[Mikhail]

Hi,
You can connect to the device, but it does not respond. Check that the Modbus device address is correct. Use https://rapidscada.net/modbus to validate the packets: 01 1E 00 00 00 06 0A 03 00 00 00 0A

[Mikhail]

Also possible that requests are not delivered to RPi by VPN.

[feltduck]

Hi,
I’ll check if the RPi doesn’t deliver the request trough VPN.
Now I have another problem. I’m trying to connect again on local and it doesn’t work.
This is the log that I’m getting:
2023-03-07 08:57:33 Establish a TCP connection with 192.168.1.103:502

2023-03-07 08:57:33 Communication session with the Device 10 “Priueba 2”, type: KpModbus, address: 10, call number: 192.168.1.103
Request element group
Send (12): 00 A9 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!
Request element group
Send (12): 00 AA 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!
Request element group
Send (12): 00 AB 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!

2023-03-07 08:57:37 Disconnect from 192.168.1.103

2023-03-07 08:57:37 Establish a TCP connection with 192.168.1.103:502

2023-03-07 08:57:37 Communication session with the Device 10 “Priueba 2”, type: KpModbus, address: 10, call number: 192.168.1.103
Request element group
Send (12): 00 AC 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!
Request element group
Send (12): 00 AD 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!
Request element group
Send (12): 00 AE 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!

2023-03-07 08:57:41 Disconnect from 192.168.1.103

2023-03-07 08:57:41 Establish a TCP connection with 192.168.1.103:502

2023-03-07 08:57:42 Communication session with the Device 10 “Priueba 2”, type: KpModbus, address: 10, call number: 192.168.1.103
Request element group
Send (12): 00 AF 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!
Request element group
Send (12): 00 B0 00 00 00 06 0A 03 00 00 00 0A
Receive (0/7):
Communication error!
Request element group
Send (12): 00 B1 00 00 00 06 0A 03 00 00 00 0A
Receive (7/7): 00 AF 00 00 00 03 0A
Incorrect MBAP Header data!

[Mikhail]

Hi,

Modbus server does not respond. You should check logs of Modbus server if it provides info.

[feltduck]

Hi,
I just reinstalled the modbus server and the scada and it’s going well.
Now the doubt that I have is, how can I export all the data to a XML?
Thanks for the help.

[Mikhail]

Hi,
Please create a new topic for the new question and provide the details.

[Author]

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