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Should RS485 be shielded?
RS485 needs 3 conductors and a shield. Many people say it’s a two-wire network but it is not. Two conductors are used to carry the RS485 Differential voltage signal. The Shield is connected to earth/ground at one end only and provides shielding against induced noise.
Can I use CAT5 for RS485?
Generally speaking CAT5 s fine for RS485. IME the first limit you hit is the series resistance driving a termination over a long cable.
What cable should be used for RS485?
A good economical solution for field wiring is to use CAT5 or CAT6 twisted pair cable. Connect each twisted pair to the same set of signal pins – TX+/TX- would be one pair of conductors, RX+/RX- another pair of conductors, and GND a third pair of conductors.
Is the CAT5 cable good enough for RS-485?
Generally speaking CAT5 s fine for RS485. IME the first limit you hit is the series resistance driving a termination over a long cable. I’ve run 250kbaud over 100m reliably. Things started getting shaky at around 200-300m. Per reference to Maxim APPLICATION NOTE 3884 How Far and How Fast Can You Go with RS-485? from Jul 25, 2006 (cited 2104-05-28):
Which is better shielded twisted cable or RS485?
It seems if there is a lot of RFI in the installation, shielded twisted cable can be justified. Rs485 is low impedance balanced , so twisting the pair helps with noise immunity as well as reducing the attenuation effect of higher baud rates due to the parallel capacitance of the wires in the cable jacket over the long lengths.
Do you need twisted wires for RS-485 Master?
However, we recommend shielding for long runs and if there is electrically noisy equipment nearby like variable speed drives. If you use shielded cable, connect the shield to earth ground at one end (generally the PC or RS-485 master). Do you need twisted wires? Yes, especially for non-shielded cable. What voltage rating do you need?
What is the data rate of CAT5 cable?
At 39Mbps and 340 feet of Cat5 cable, the driver output of Figure 2 exhibits an eye pattern in which signals cross in the middle of the eye—a condition indicating possible bit errors. The Maxim device at the same data rate, however, (Figure 3) shows no such condition.