Number of RTUs

A

Thread Starter

Adi Bichea

If i have in my system more than 256 of RTUs (with modbus protocol). Each RTU has an adress (1 to 1000). I want to know how to access RTU number 983?
 
Could you fill us in on why this might be more than just an academic question?

983 RTUs??

on Modbus???

A joke maybe???
 
Modbus RTU supports addresses 1-247. You can make or get a device to "extend" your addressing, but by default Modbus RTU will not work by itself.

It would probably be easier and more reliable to make 5 legs, each with 200 slaves.
 
Or maybe not.

I worked on a system with over 1200 RTUs spread over a radius of 300 miles, each talking ModBus, and all communicating to a central control room.

Admittedly there were a few layers of data concentrators as well!
 
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