Unstable Modbus/TCP connection to Multiplus 2 GX

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sascha-brinkmann asked Jan 9, '23

Unstable Modbus/TCP connection to Multiplus 2 GX

I'm operating a Multiplus 2 GX with activated Modbus TCP (see Picture 1). A separate Raspberry Pi which is running Node-Red connects to the Modbus/TCP endpoint. The modbus TCP connection is used to read information from the Multiplus and to control the ESS based on my dynamic energy tariff. While the communication itself works quite well, the connection to the Multiplus is unstable and breaks regularly (see Picture 2). To be able to reconnect I have to move the the modbus connection in the editor slightly and re-deploy in Node-Red. I've tried to optimize the connection settings (see Picture 3) towards the Multiplus but without any impact.

From my current perspective there is no reason for the instability. Within the VRM portal there are no connection issued and the state of the Multiplus is reported without data gaps or connection issues.

Picture 1

Picture 2

Picture 3

Multiplus-II Node-RED Modbus TCP

bildschirmfoto-2023-01-09-um-142951.png (133.6 KiB)

1673271500367.png (66.4 KiB)

bildschirmfoto-2023-01-09-um-142502.png (238.0 KiB)

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sascha-brinkmann answered · Jan 16, 2023 at 06:53 AM

I've updated the modbus library to the currently latest available version and this seem to fix the instabilities. My settings within the package.json is as following in the dependencies section:

"node-red-contrib-modbus": "^5.25.0"

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Modifications Space

Node Red Space

Answer 1 · 2023-01-10T17:48:35Z

wkirby answered · Jan 10, 2023 at 05:48 PM

That is quite unusual. I regularly request 25+ FC3 reads every 5 seconds all day every day and I have never had a problem.
Have you had a look at the resources on your GX device? Maybe use top to make sure that the GX is not struggling with resources first.

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