# Modbus Serial - Whole bus disconnects when one device drops

**URL:** <https://discourse.nodered.org/t/modbus-serial-whole-bus-disconnects-when-one-device-drops/48555>\
**Category:** General\
**Created:** [18 July 2021 18:57 UTC](https://discourse.nodered.org/t/modbus-serial-whole-bus-disconnects-when-one-device-drops/48555 "2021-07-18T18:57:23Z")\
**Posts on this page:** 5\
**Page:** 2

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**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [23 July 2021 09:45 UTC](https://discourse.nodered.org/t/modbus-serial-whole-bus-disconnects-when-one-device-drops/48555/21 "2021-07-23T09:45:13Z")

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Yes, that is true, however would you want incomplete results?

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**Author:** ![Weller1](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/weller1/32/45114_2.png) [@Weller1](https://discourse.nodered.org/u/Weller1)\
**Post date:** [23 July 2021 13:28 UTC](https://discourse.nodered.org/t/modbus-serial-whole-bus-disconnects-when-one-device-drops/48555/22 "2021-07-23T13:28:28Z")

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You are correct. But it also intervenes with the idea of the stable system in my case. In my application if one device lose power/break down, I still want the rest of the system to function properly. If they are in series, one breakage would result all the messages from the same series to be affected.

Correct me if im wrong

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**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [23 July 2021 13:32 UTC](https://discourse.nodered.org/t/modbus-serial-whole-bus-disconnects-when-one-device-drops/48555/23 "2021-07-23T13:32:16Z")

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I see what you are saying. I was addressing the other issue

> [@Weller1](#):
>
> Clearly if I poll each of my 9 devices with the flex-getter like in the picture (with 1 second inject interval). The answers will start to stutter and messages come in very randomly. It works correctly but its not the action I want. I would like to have even flow of messages from the devices.

You could, i suppose, use one trigger to start the flow, with an increasing delay between each (to space out the calls to the getter).

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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:** [23 July 2021 14:28 UTC](https://discourse.nodered.org/t/modbus-serial-whole-bus-disconnects-when-one-device-drops/48555/24 "2021-07-23T14:28:01Z")

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> [@Weller1](#):
>
> I started to think if the msg go through the Flex Getter if it dont get respond?

There is an option in the Flex Getter that even a request fails, it will still produce a msg.  
Try out the option : **Empty msg on fail**

![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/0/5/05380d860a4dbcf98778d3c83b53faec8b6fb7be.png)

That would still trigger the next Getter read in the series

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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:** [6 August 2021 14:28 UTC](https://discourse.nodered.org/t/modbus-serial-whole-bus-disconnects-when-one-device-drops/48555/25 "2021-08-06T14:28:49Z")

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Closed on 6 August 2021 14:28 UTC

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