MODBUS maximum wire length 2

[guilio2010]

I'm going through calculations for various equipment and the one item I haven't found much information on was calculation the maximum distance for MODBUS communication based on wire size. I seen general rule of thumbs and basic equations in regards to data rate and distance, but I would think there would be something out there that would calculate your distance based on wire size for resistance (expected Vdrop of the signal) and the capacitance. For voltage drop conditions, would this be just your 12V signal voltage drop across the wire and capacitance of the wire affects the signal?

Thanks,
guilio

 

[IRstuff]

The voltage levels are essentially explained in Table 2 of

http://www.ti.com/lit/an/slla070d/slla070d.pdf.

There are limitations on the common mode offset due to the circuit design.

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