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Inconsistance cumulative revolution data

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Total Posts: 12

Joined 2022-10-27

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Hi,
I have a bike trainer, that included ANT+ protocol for communication.
So far I have been able to receieve information on my pc of this bike trainer (cumulative revolution information) by using the channel configuration of combined bike speed and cadence display.i.e(slave)
The problem that I have is that the data I receieve are not consistent. For example if I turn the shaft of the trainer 20 times (20 revolution of shaft trainer) I receieve 1 cumulative revolution. then If I repeat it and turn the shaft 30 times I will see 1 other revolution via the ANT+ message and it's not consistent.
please check the picture to understand better what is my problem.

What I expect is that every time that I rotate the shaft of the trainer a constant number (for example 20 times), it will be counted as 1 revolution.
For example everytimes that I rotate the bike trainer shaft 20 times then the ant+ message that I receieve will add 1 revolution.
I just want to have this data to be consistent and I don't know if I need to do some configuration for the master device (bike trainer) via the code, because right now I just use the table of slave chanel configuration table (combined bike speed and candence display).

I appreciate your help and guide,
Meysam.      

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Total Posts: 370

Joined 2012-06-27

PM

The bike speed portion of the profile is based on wheel revolutions, not revolutions of the trainer drum.

Cadence, if calculated by the trainer, would likely be based on the gear ratio being known. You would need to reach out to the trainer manufacturer to understand more about this.      

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Ian Haigh

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Total Posts: 12

Joined 2022-10-27

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First, Thanks for your reply.
About the speed I know that the revolutions is based the wheel and not the trainer drum. but it changes nothing. Because it's just a coeficient between diameter of wheel and the diameter of trainer drum.
Imagine 1 wheel rotation is equal to 30 turns of trianer drum. so each time that the trainer drum is rotated 30 times then I should have 1 revolution of the wheel. like the picture below. But as you said I should contact the manufacturer of bike trainer about this. Thanks in advance.
     
Rank

Total Posts: 12

Joined 2022-10-27

PM

First, Thanks for your reply.
About the speed I know that the revolutions is based the wheel and not the trainer drum. but it changes nothing. Because it's just a coeficient between diameter of wheel and the diameter of trainer drum.
Imagine 1 wheel rotation is equal to 30 turns of trianer drum. so each time that the trainer drum is rotated 30 times then I should have 1 revolution of the wheel. like the picture below. Shouldn't it be like this ? or maybe I'm wrong!. But as you said I should contact the manufacturer of bike trainer about this.
Thanks in advance.
     

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Total Posts: 370

Joined 2012-06-27

PM

Yes you will have to take this up with the trainer manufacturer. There is nothing in the ANT+ profile that would explain this.

It is possible they have tried to implement some sort of filtering such that equation 5-1 is accurate, but the revolutions are not. This would lead to inaccurate distance with equation 5-2.      

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Ian Haigh

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Total Posts: 370

Joined 2012-06-27

PM

Yes you will have to take this up with the trainer manufacturer. There is nothing in the ANT+ profile that would explain this.

It is possible they have tried to implement some sort of filtering such that equation 5-1 is accurate, but the revolutions are not. This would lead to inaccurate distance with equation 5-2.      

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Ian Haigh