RS-485 Communication testing with MAX485

As we know about RS-232 communication protocol, I'm going to try RS-485 communication between two nodes. RS-485 can support multiple slaves and mostly used in industrial applications with high separation distance between nodes. I recently got 10pcs of MAX485 IC from ebay for $1 which is a RS-485 transceiver. I also got  USB to RS-485 convertor based on CH430 + MAX485. I'm using another USB-UART convertor based on PL2303 for this test setup. So, I have two USB-UART chips connected using two MAX485 ICs in between,which provides the RS-485 communication.

My test setup according to MAX485 datasheet.
(Image extracted from datasheet)











As MAX485 is half duplex, I have to use one as TX with following setup. I'm using my USB-RS485 adapter as  RX and there is no need of manual setting as RX.











My TX setup on breadboard:

















My RX setup, the one is right is USB-RS485 convertor:
















Test results :
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3 comments:

  1. Hi,
    It looks like the diagram need to be corrected. The RO must be connected to Rx and the DI connected to TX, right?

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    Replies
    1. Agreed. I've been working with these lately and RO is Receiver Out, DI is Data In (connected to the chip/converter Tx).

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    2. Sorry guys, just saw the mistake, I'll correct it, thanks for pointing it out :)

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