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Can anybody throw some light on RS-485 communication between Raspi and various sensors.

Note: I would like to use it with Pyhton 2.7

Can i connect ADM485 to UART( Tx,Rx) of raspberry pi, I want too use minimalmodbus to communicate with Arduinos receiving information from multiple temperature sensors. Any references to this? I read the documentation of minimalmodbus, sounds great can i go forward or any other better python mdoules for a beginner like me.

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1 Answer 1

I do not think you will be able to directly connect the RS-485 to the RPi with software bitbanging.

It think the easiest way would be to use a USB <-> RS-485 device. Then you can use the USB as a serial port and let the rest happen as it should.

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I did find something like that at Farnell and it says it supports Linux 2.4+ - But the driver might need to get tweaked to work on ARM version of Linux. Then just use Python or whatever using built in Serial Port tools and code!

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Thanks to Phil Vallone for providing a solution to use the FTDI chip on the Pi

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+1 Here is a answer which provides a link to the FTDI drivers raspberrypi.stackexchange.com/questions/14894/… –  PhillyNJ May 19 '14 at 14:29
Thanks for the link. Really awesome that there is a solution. I will just add references to my answer also. THanks again. –  ppumkin May 19 '14 at 14:38
Happy to Help - Here is the text version. ftdichip.com/Drivers/D2XX/Linux/ReadMe-linux.txt –  PhillyNJ May 19 '14 at 14:41
adding detail to ppumkin's answer : RS485 uses voltage levels that are different than the Pi has available. And also uses what is called "differential" output –  Marla May 19 '14 at 14:57
can't i use UART pins Rx and Tx ? whats the necessity in going for USB to UART convertion when i have UART pins on raspberry pi. i will use ADM 485 . will this work? –  Ruthvik Vaila May 26 '14 at 9:03

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