# Problem to get robust Modbus connection to SMA Inverter

**URL:** <https://discourse.nodered.org/t/problem-to-get-robust-modbus-connection-to-sma-inverter/66343>\
**Category:** General\
**Tags:** modbus\
**Created:** [12 August 2022 06:36 UTC](https://discourse.nodered.org/t/problem-to-get-robust-modbus-connection-to-sma-inverter/66343 "2022-08-12T06:36:09Z")\
**Posts on this page:** 5\
**Page:** 2

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**Author:** ![UnborN](https://avatars.discourse-cdn.com/v4/letter/u/4491bb/32.png) [@UnborN](https://discourse.nodered.org/u/UnborN)\
**Post date:** [15 August 2022 09:01 UTC](https://discourse.nodered.org/t/problem-to-get-robust-modbus-connection-to-sma-inverter/66343/21 "2022-08-15T09:01:13Z")

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> [@klaus123](#):
>
> Yesterday evening I reduced to 2 reading all 5 minutes and so far today things run fine

maybe its not hardware or heat related .. maybe just the possibility that you are making to many requests.  
The following from the SMA website .. [Modbus FAQ](https://www.sma.de/en/products/product-features-interfaces/modbus-protocol-interface.html)

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/4/3/43b45d29f45886c06d0b39f40d0a4110a1c16c30.png)

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**Author:** ![klaus123](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/klaus123/32/39677_2.png) [@klaus123](https://discourse.nodered.org/u/klaus123)\
**Post date:** [15 August 2022 09:09 UTC](https://discourse.nodered.org/t/problem-to-get-robust-modbus-connection-to-sma-inverter/66343/22 "2022-08-15T09:09:24Z")

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Interesting - thank you

Is it possible that NR keeps the connection open after the use of modbus- getter?  
If YES can I close it somehow?

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**Author:** ![UnborN](https://avatars.discourse-cdn.com/v4/letter/u/4491bb/32.png) [@UnborN](https://discourse.nodered.org/u/UnborN)\
**Post date:** [15 August 2022 09:14 UTC](https://discourse.nodered.org/t/problem-to-get-robust-modbus-connection-to-sma-inverter/66343/23 "2022-08-15T09:14:42Z")

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Very good question .. i was wondering about that also ..  
Its not so much related to Node-red but depends on the **Modbus** nodes and the **modbus-serial** library they use .. how well they handle open connections .. and if its already open, not to open another one .. complicated stuff .. i dont know the answer to that.

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**Author:** ![klaus123](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/klaus123/32/39677_2.png) [@klaus123](https://discourse.nodered.org/u/klaus123)\
**Post date:** [16 August 2022 18:48 UTC](https://discourse.nodered.org/t/problem-to-get-robust-modbus-connection-to-sma-inverter/66343/24 "2022-08-16T18:48:26Z")

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Short update: I reduced the readings via ModBus/TCP to 2 every 5 minutes - so far it is running fine now.

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [15 October 2022 18:48 UTC](https://discourse.nodered.org/t/problem-to-get-robust-modbus-connection-to-sma-inverter/66343/25 "2022-10-15T18:48:51Z")

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Closed on 15 October 2022 18:48 UTC

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