Modbus Rtu to Modbus Tcp convertion !

I have 130 devices connected in series with Rs485 by Modbus RTU protocol.
I know that RS485 has a limitation of 32 devices per segment.
And i can manage that by adding repeaters ..
My question is , if i make a convertion of modbus RTU to Modbus Tcp , the problem of limitation can be solved ? Without adding repeaters !
The process is like that :
Rs485 ==> CONVERT TO Ethernet (tcp) ==> fibre optique ==> Convertion to Ethernet again ==> convertion to Rs485 again and connect to the SCADA .
 
Are you trying to solve a communication problem on your Modbus RTU network that you believe is caused by overloading the bus (i.e. having 130 devices on one RS-485 bus)?

I know that RS485 has a limitation of 32 devices per segment.
The limitation of RS-485 is actually defined as 32 "Unit Loads". For older RS-485 devices, it may be true that 1 device presents 1 unit load on the bus. However, nowadays, there are many devices out there that present a fraction of a unit load, such as 1/8 or even 1/10, onto the RS-485 bus. For example, with 1/8 unit load devices, you can have up to 256 devices on the RS-485 bus. You should contact the vendor of your Modbus RTU devices to find out the unit load of each device. This will allow you to determine the true device limit for your network.

My question is , if i make a convertion of modbus RTU to Modbus Tcp , the problem of limitation can be solved ? Without adding repeaters !
Well, yes, this could work. But why do you want to do this? RS-485 to Ethernet/Fiber converters are almost certainly more expensive than RS-485 repeaters. Unless you are trying to solve a specific problem that RS-485 repeaters cannot solve, I don't see a reason to use RS-485 to Ethernet/Fiber converters over RS-485 repeaters.
 
Are you trying to solve a communication problem on your Modbus RTU network that you believe is caused by overloading the bus (i.e. having 130 devices on one RS-485 bus)?


The limitation of RS-485 is actually defined as 32 "Unit Loads". For older RS-485 devices, it may be true that 1 device presents 1 unit load on the bus. However, nowadays, there are many devices out there that present a fraction of a unit load, such as 1/8 or even 1/10, onto the RS-485 bus. For example, with 1/8 unit load devices, you can have up to 256 devices on the RS-485 bus. You should contact the vendor of your Modbus RTU devices to find out the unit load of each device. This will allow you to determine the true device limit for your network.


Well, yes, this could work. But why do you want to do this? RS-485 to Ethernet/Fiber converters are almost certainly more expensive than RS-485 repeaters. Unless you are trying to solve a specific problem that RS-485 repeaters cannot solve, I don't see a reason to use RS-485 to Ethernet/Fiber converters over RS-485 repeaters.
Thank you for your reponse ,
The reason that i'm using Ethernet/fibre converters is to make the communication between the DCS and the other devices through a fiber cable , because of the long distance and to ensure a fast real time response.
 
I have 130 devices connected in series with Rs485 by Modbus RTU protocol.
I know that RS485 has a limitation of 32 devices per segment.
And i can manage that by adding repeaters ..
My question is , if i make a convertion of modbus RTU to Modbus Tcp , the problem of limitation can be solved ? Without adding repeaters !
The process is like that :
Rs485 ==> CONVERT TO Ethernet (tcp) ==> fibre optique ==> Convertion to Ethernet again ==> convertion to Rs485 again and connect to the SCADA .
Try using https://www.serial-over-ethernet.com/. Remote access will not be limited by the number of connections. the only moment it all comes down to finance. For the test, you can take the trial version. Well, it's cheaper than CommFront.
 
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