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0 votes
1,523 views 6 comments
by anonymous

Hi.

I've read this article: https://wiki.teltonika-networks.com/view/RUT955_Monitoring_via_Modbus,
that explains how to read the RUT955 router internal registers with  modbus read  from a Linux terminal.

Is it possible to use the  modbus read  (or another utility) from a Linux terminal to request the router's slave device's registers?

The connection scheme is the following:

  • a slave device (PLC) connected to the RUT955 via RS485
  • a Linux PC connected to the RUT955 via TCP (a LAN port)
    
 ┌────┐    TCP    ┌─────┐    RS485    ┌─────┐
 │ PC │ <-------> │ RUT │ <---------> │ PLC │
 └────┘           └─────┘    Modbus   └─────┘
    

2 Answers

0 votes
by anonymous
Hello,

Yes, this is possible, but you will need to use a really limited method for that.

You will need to create a tunnel between your PC and the device that is a master of Modbus. Then SSH into that router and control slaves from that point.

EB.
by
As I understand, "the device that is a master of Modbus" is the router in this case.
I can connect via SSH to the router, but cannot get the registers of its slave device.
by anonymous
No, you can do it. But it will exactly require you to SSH into Master router to reach its slave devices.
by anonymous
OK. But how do I read the slave devices info when connected to the router via SSH? That's the question.
by anonymous
In this question thread, there's a command with all the things you can do with it.

https://community.teltonika-networks.com/24215/need-an-example-of-modbus-read-write-request-bash-script-cli

EB.
by anonymous
Thanks a lot.
0 votes
by anonymous
Hi.

You can use RUT955 as Modbus Gateway. I did something like that with Python (pymodbus), a RUT955 and Delta PLC.
by anonymous

I saw there's an option for Modbus Gateway in the Services -> RS485 section.
So this means the router will be an intermediary node between the PLC and the Linux PC?
And the pymodbus should be installed on the Linux side, right?
Thanks.