ANT Forum

Hello,
In the standard's document ANT+_Device_Profile_-_Bicycle_Power_-_Rev3.0.pdf Table 15-4 page 66 the Fractional battery voltage is noted to have a unit of "1/256 (V)".

I would expect this in stead to read "1/256" or possibly "100/256 %". The latter to emphasize that it is a ratio - not a voltage.

This is surely a small detail but consistency improves clarity.
Are my observations correct?
     

Hi Larsen,

Thanks for your post. It's always good to have the documents 100% accurate, so I welcome any corrections.

I checked the bike power doc, and in this case it is correct. The field should contain a fraction of a Volt. The descriptive bit field in byte 7 contains the whole number of volts, and is then combined with the fractional voltage in byte 6 to indicate the total voltage.

I.e. 4V in Byte 7, 0.72V in byte 6 => 4.72V overall.

Please check the ANT+ Common pages document for full details of this and other common pages.

Thanks,

Kat      

Hello Kat,
Thanks for the clarification. Now the unit of Volt makes sense. I mistakenly imagined it as the fraction = (present voltage)/(nominal voltage).

To improve clarity maybe add the "Example of Battery Voltage Page Data" section from the common_Data_pages document, or simply a cross reference.But..

Question: The tables "Table 6-9. Common Data Page 82 - Battery Status" in common_data_pages_Rev2.4 differs from the almost identical
"Table 15-4. Global Data Page 82 - Battery Status" in Device_Bicycle_Power_Rev3.0.

The description of byte 1 and 2 differ in the two tables. In one the bytes are reserved, in the other identify and count of the number of batteries. Is this logical? I would expect both page descriptors to be equal in usage and definition.
regards
     

Hej!

If you check the latest version of the ANT+ Bike Power Device Profile you will see that the tables match up (4.0). Being able to identify which battery is low is a new feature that was added this year, and we are in the process of updating the descriptions in the rest of the device profiles to match. Unless there are special notes for the way a page is used in a given device profile we will simply be referring to the ANT+ Common Pages doc in future.

Mvh,

Kat      

Hej Kat,

Thanks, this restores order in my circles. I was using revision 3.0 of the Bike Power document.
I must make sure I use the latest document revisions.

This makes me wonder if there is a means of subscribing to document update notifiers. If not - it could be useful.

mvh henning      

Hej Henning,

There is! It is currently not working properly though, and I am trying to get it fixed. But in theory you can subscribe to our critical bytes RSS feed (I have mine set up in Outlook) and we update it every time we upload a new document or software version.

http://www.thisisant.com/feeds/tech_bulletin/critical_bytes/

Enjoy! Og go' weekend!

Kat