# Node red Event loop blocking when modbus timedout

**URL:** <https://discourse.nodered.org/t/node-red-event-loop-blocking-when-modbus-timedout/92968>\
**Category:** General\
**Tags:** modbus\
**Created:** [7 November 2024 13:35 UTC](https://discourse.nodered.org/t/node-red-event-loop-blocking-when-modbus-timedout/92968 "2024-11-07T13:35:02Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![pbhanu368](https://avatars.discourse-cdn.com/v4/letter/p/d9b06d/32.png) [@pbhanu368](https://discourse.nodered.org/u/pbhanu368)\
**Post date:** [7 November 2024 13:35 UTC](https://discourse.nodered.org/t/node-red-event-loop-blocking-when-modbus-timedout/92968/1 "2024-11-07T13:35:02Z")

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Whenever the modbus timedout while reading registers, my node red event loop is blocking for a specific time, how to resolve this ?

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**Author:** ![knolleary](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/knolleary/32/3_2.png) [@knolleary](https://discourse.nodered.org/u/knolleary)\
**Post date:** [7 November 2024 13:44 UTC](https://discourse.nodered.org/t/node-red-event-loop-blocking-when-modbus-timedout/92968/2 "2024-11-07T13:44:54Z")

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Which modbus nodes are you using?

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [7 November 2024 13:51 UTC](https://discourse.nodered.org/t/node-red-event-loop-blocking-when-modbus-timedout/92968/3 "2024-11-07T13:51:36Z")

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How do you know it is blocking?

Also, if you remove the output wires from the modbus node and replace with just a debug node does it still block?

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**Author:** ![pbhanu368](https://avatars.discourse-cdn.com/v4/letter/p/d9b06d/32.png) [@pbhanu368](https://discourse.nodered.org/u/pbhanu368)\
**Post date:** [7 November 2024 14:50 UTC](https://discourse.nodered.org/t/node-red-event-loop-blocking-when-modbus-timedout/92968/4 "2024-11-07T14:50:06Z")

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node-red-contrib-modbus

Using Modbus TCP

It is happening for when i use complex flows, when using single modbus flow its good

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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:** [7 November 2024 15:02 UTC](https://discourse.nodered.org/t/node-red-event-loop-blocking-when-modbus-timedout/92968/5 "2024-11-07T15:02:02Z")

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Please answer:

> [@Colin](#):
>
> How do you know it is blocking?

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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:** [5 February 2025 15:02 UTC](https://discourse.nodered.org/t/node-red-event-loop-blocking-when-modbus-timedout/92968/6 "2025-02-05T15:02:58Z")

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