Timeline for Best practice to wire RS485 2 wire device to RS485 4 wire device
Current License: CC BY-SA 4.0
18 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| S Oct 15, 2022 at 6:30 | history | suggested | Obie 2.0 | CC BY-SA 4.0 |
https://modbus.org/docs/Client-ServerPR-07-2020-final.docx.pdf
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| Oct 15, 2022 at 2:28 | review | Suggested edits | |||
| S Oct 15, 2022 at 6:30 | |||||
| Aug 24, 2021 at 6:59 | vote | accept | FrougeurPro | ||
| Aug 24, 2021 at 6:59 | answer | added | FrougeurPro | timeline score: 0 | |
| Aug 14, 2021 at 3:02 | review | First posts | |||
| Aug 14, 2021 at 6:20 | |||||
| Aug 12, 2021 at 18:03 | history | edited | Null♦ | CC BY-SA 4.0 |
don't use "edit" in the text since we can see the edit history
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| Aug 12, 2021 at 3:09 | comment | added | Dave Tweed | Yes, you shouldn't try to mix them. | |
| Aug 11, 2021 at 14:30 | comment | added | Marko Buršič | Which type of RS485/Ethernet converter are you using. A modbus master shall send query, purge the receive buffer and start receiving, after the last character is sent. Otherwise it should discard the echo garbage. It also needs a RTS handshake to enable/disable the TX, probably the idea of using a ETH to RS485 is not the best one, you should ask the manufacturer how to use this device with Modbus. The correct device would be Modbus TCP/IP to Modbus RTU converter. | |
| Aug 11, 2021 at 14:10 | comment | added | FrougeurPro | @DaveTweed I didn't quite get the link between your comment and the answer you linked. Is it implying that you shouldn't mix RS485 and RS422 (RS485 4 wire if i understood correctly) ? | |
| Aug 11, 2021 at 14:01 | answer | added | Dirk Bruere | timeline score: 0 | |
| Aug 11, 2021 at 14:01 | comment | added | FrougeurPro | @MarkoBuršič I am using pyModbus for my master implementation, could you elaborate on how it is bad exactly ? | |
| Aug 11, 2021 at 13:55 | history | edited | FrougeurPro | CC BY-SA 4.0 |
Included a sketch
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| Aug 11, 2021 at 10:38 | comment | added | Dave Tweed | More importantly, the 4-wire device is not shutting down its transmitter when it should be listening for the device response. See electronics.stackexchange.com/a/69898/11683 | |
| Aug 11, 2021 at 10:26 | review | Close votes | |||
| Aug 12, 2021 at 18:03 | |||||
| Aug 11, 2021 at 10:07 | comment | added | SteveSh | A schematic or sketch is always helpful. Please provide something along that line. | |
| Aug 11, 2021 at 10:05 | comment | added | Marko Buršič | you have a bad modbus master implementation. | |
| Aug 11, 2021 at 9:33 | comment | added | Lundin | "The slave device is RS485 2 wire" ... "As of now, I wired both Tx+ and Rx+ to the slave's Data+ pin" How does this make any sense? Does it have 1 differential signal or 2 differential signals? Or does it have no differential signal at all...? | |
| Aug 11, 2021 at 9:13 | history | asked | FrougeurPro | CC BY-SA 4.0 |