Hi all, I'm using the node-red-contrib-modbus node, with two slave devices with addresses 1 and 101. Both have the same settings, for RTU-BUFFERED: Baud rate: 9600 Data bits: 8 Stop bits: 1 Parity: None I've confirmed that there are no wiring issues and all comms are good. I'm having an issue w…

I've done some further digging and it looks like my issue is identical to this: Multiple Modbus RTU Slaves using the same port pon Raspberry Pi opened 09:59PM - 03 Jul 19 UTC (UTC) closed 01:56PM - 17 Nov 19 UTC…

Also this: Queue messages by server rather than by unit-id opened 02:07PM - 08 Feb 19 UTC (UTC) [dtwaydd] dtwaydd I'm submitting a ... (check one with "x") Feature (…

Ok...so it looks like there's a fundamental flaw in the node-red-contrib-modbus node whereby you can only set up and communicate with one Modbus RTU slave per serial port, which defeats the object of Modbus...investigating further. It seems like the contributor is away, however this is such a major…

When dealing with Modbus RTU, see to it that the communication traffic should be consider. When Master is trying to poll data from Slave 1, the master should dedicate its connection to the Slave 1, the same thing to slave 2. WIth modbus RTU, only 1 slave can be connected at a time. Maybe with your s…

I've tried this using the node-red-contrib-serial-modbus node, with success. This proves that the hardware setup is correct and that multiple serial slaves can be interfaced with, as per the modbus spec. I can't use this node for my setup however as it gives no ability to tune timeouts, reconnects e…

Feel free to contribute if are able to test!

Hi @bianco-royal - awesome to hear from you :slight_smile: I'm just working my way through the codebase. I'm not a native javascript developer so it's not second nature to me, so may struggle to improve. It looks like there's a need to initialise and queue based on the server being used, opposed to …

I could build a pre-release with some ideas to fix it and you could test it.(?)

I'd be more than happy to do this @bianco-royal - would you like to continue the comms here or shall I open a new issue on GitHub where the both of us can track better? Thanks :slight_smile:

Please, open an issue for that with reference to this!

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Multiple Modbus RTU Slaves causes error

Industrial

Hasitha_Sudasinghe 25 May 2020 07:40 13

Can you please help me with my case?

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Multiple Modbus RTU Slaves causes error

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