modbus rtu maximum length of cable

[Kataeb]

what is the maximum length of cable can modbus rtu go? do you have any curve showing cable distance versus baudrate?

 

[tragically1969]

what is the maximum length of cable can modbus rtu go? do you have any curve showing cable distance versus baudrate?

Google is your friend:

https://www.maximintegrated.com/en/app-notes/index.mvp/id/3884

and from Wikipedia:

Since it uses a differential balanced line over twisted pair (like RS-422), it can span relatively large distances up to 1,200 m (4,000 ft). A rule of thumb is that the speed in bit/s multiplied by the length in meters should not exceed 108. Thus a 50 meter cable should not signal faster than 2 Mbit/s.

 

[Mickey]

what is the maximum length of cable can modbus rtu go? do you have any curve showing cable distance versus baudrate?

RS232 or RS485/RS422?

RS232 = 50ft (I have seen as much as 150ft at 9600 baud rate, good cabling)

RS485/RS422 see tragically1969's post.

 

[danw]

Predicated on using low capacitance comm cable: