ISO3088 - RS485 transceiver - external wiring between two ISO3088 without GND2

gerard TRIC

Other Parts Discussed in Thread: ISO3088

I have two equipments, separated from 600m, equipped with ISO3088 RS485 transceivers. The link of communication between them consist of a cable composed of only two wires.

Can I use one wire for the output A+ and the other wire for the output B-, without to connect the GND2 ?

In fact, How could we connect these two transceivers with only two wires ?

Thank you.

Gérard TRIC

over 10 years ago

0 John Griffith over 10 years ago

TI__Mastermind 21523 points

Hi Gérard,

Since RS485 has such a high common mode range for the driver and the receiver ground wires are not needed.

A colleague of mine wrote the following article that explains this.

http://www.planetanalog.com/author.asp?section_id=483&doc_id=562062&

Basically the isolated side of all the transceivers will float to the same potential, thus reducing the ground potential difference (GPD) to almost nothing.

Thanks,

John

0 gerard TRIC over 10 years ago in reply to John Griffith

Prodigy 20 points

Hi John,

Wonderfull !! Thank very much for your answer.

I am going to analyse the article of your colleague and if this is applicable for our application, it will be fantastic !!

I shall inform you after our tests.

Me, the AREVA Group and EDF, thank you a lot

Gérard

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ISO3088 - RS485 transceiver - external wiring between two ISO3088 without GND2