# Critical Bus load

**URL:** <https://forum.opencyphal.org/t/critical-bus-load/493>\
**Category:** Applications & Usage\
**Created:** [May 27, 2019, 3:32pm UTC](https://forum.opencyphal.org/t/critical-bus-load/493 "2019-05-27T15:32:44Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Mo5tar97](https://forum.opencyphal.org/letter_avatar_proxy/v4/letter/m/c89c15/32.png) [@Mo5tar97](https://forum.opencyphal.org/u/Mo5tar97)\
**Post date:** [May 27, 2019, 3:32pm UTC](https://forum.opencyphal.org/t/critical-bus-load/493/1 "2019-05-27T15:32:44Z")

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Hello  
I am trying to use the UAVCAN to establish a triplex redundant model for controlling a quad so I created some messages to be sent over the can bus and I expect that my bus load will be about 65% (measured by CAN vector box using CANoe software) so my question is there is a critical range for the bus load I am not supposed to exceed? and if yes how much is it ?

Thanks in advance

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**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\
**Post date:** [May 27, 2019, 3:45pm UTC](https://forum.opencyphal.org/t/critical-bus-load/493/2 "2019-05-27T15:45:34Z")

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> [@Mo5tar97](#):
>
> is there is a critical range for the bus load I am not supposed to exceed? and if yes how much is it ?

UAVCAN does not limit the maximum bus utilization.

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**Author:** ![Mo5tar97](https://forum.opencyphal.org/letter_avatar_proxy/v4/letter/m/c89c15/32.png) [@Mo5tar97](https://forum.opencyphal.org/u/Mo5tar97)\
**Post date:** [May 28, 2019, 1:42pm UTC](https://forum.opencyphal.org/t/critical-bus-load/493/3 "2019-05-28T13:42:00Z")

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I know but I mean for safety percussions should I keep my bus load in certain range to not overload the CAN bus and data get lost ?

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**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\
**Post date:** [May 31, 2019, 8:28am UTC](https://forum.opencyphal.org/t/critical-bus-load/493/4 "2019-05-31T08:28:37Z")

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There is no one-size-fits-all bus utilization limit. You should analyze your bus from the standpoint of latency constraints per every type of message exchanged over it; this question is briefly explored in the section 4.1.4 “Transfer priority” of the Specification: [https://new.uavcan.org/specification/UAVCAN\_Specification\_v1.0.pdf;](https://new.uavcan.org/specification/UAVCAN_Specification_v1.0.pdf;) also, this thread may also be of relevance: [Transfer priority level mnemonics](https://forum.opencyphal.org/t/transfer-priority-level-mnemonics/218)