# Function filter

**URL:** <https://discourse.nodered.org/t/function-filter/32869>\
**Category:** General\
**Created:** [14 September 2020 12:22 UTC](https://discourse.nodered.org/t/function-filter/32869 "2020-09-14T12:22:43Z")\
**Posts on this page:** 1\
**Showing post:** 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:** [14 September 2020 12:26 UTC](https://discourse.nodered.org/t/function-filter/32869/2 "2020-09-14T12:26:28Z")

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> [@pm.integrator](#):
>
> Considering that I have to poll (100 ms) to have the calls updated from system A, if there are no variations to system B the same data is sent, but I should apply a filter or something that only passes the variations coming from system A.

Sounds like you need to use the RBE node. It only allows a msg to pass if it has changed.

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