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Topic: NMEA 0183 and RS-422 receiving (Read 2221 times) previous topic - next topic

skyjumper

Hi All...

I need to recieve two to three channels of NMEA 0183 and send one channel. I looked around for a level converter chip like a MAX232 but for RS-422, but no luck. Is there an easy circuit or chip to use to convert RS-422 to TTL, ideally with electrical isolation?

Thank you.

CrossRoads

#1
Apr 09, 2011, 05:52 am Last Edit: Apr 09, 2011, 05:57 am by CrossRoads Reason: 1
You mean a part like the MAX485, or one of its quad versions?

http://www.maxim-ic.com/datasheet/index.mvp/id/1111

quad TX
http://datasheets.maxim-ic.com/en/ds/MAX3030E-MAX3033E.pdf

quad RX
http://datasheets.maxim-ic.com/en/ds/MAX3093E-MAX3094E.pdf
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

skyjumper

Yes, very much like that Bob, thank you! I guess you now know what's coming ;-)


CrossRoads

Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

skyjumper

I also ran accross someone who had a line of chips with really good isolation built in. I'll have to find those and post. It was pretty early when I saw them and now I can't remember what company it was :-(

Graynomad

To get isolation you have to use a chip with built in power supply isol. There are many for RS485, MAX3157 can handle a huge ground difference and they call it isolated but I haven't read the specs to see if that's really the case.

MAX1480/1490 are really isolated and ADUM2486/82/87 are as well I think.

Another way to do it is use simple 5v isolation chips (or optocouplers) and a small isol power supply. Look at ISO7240/1/2/3, ISO7220/1, IL15/16/17, ADUM1210.

______
Rob



Rob Gray aka the GRAYnomad www.robgray.com

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