ANT Forum

Hi, I'm getting to grips with hr messages...

I am working with a FIT file from a Fenix 5 and it's the first time that I've seen theses hr messages.

hr
- timestamp
- fractional_timestamp
- time256
- filtered_bpm (array)
- event_timestamp (array)
- event_timestamp_12 (array)

Running the Java FitCSVTool from the SDK, I get the following fields and values:

One data message containing:
timestamp 879679693
event_timestamp 4037059.807
fractional_timestamp 0.806640625
filtered_bpm 71

Then a series of data messages containing (e.g.):
filtered_bpm 71|71|71|71|71|71|71|71
event_timestamp_12 200|68|196|176|208|91|206|187|3|162|241|44
event_timestamp 4037061.1953125|4037063.06640625|4037064.171875|4037065.4345703125|4037066.951171875|4037068.0576171875|4037068.408203125|4037068.7021484375

I understand that I am supposed to map the filtered_bpm values to the relevant record messages using a combination of the first timestamp and the event_timestamps, but I cannot figure this out:

1. I don't know what the fractional_timestamp is and can't find much in the literature about it.

2. event_timestamps are to many decimal places and the difference between successive values varies considerably.

3. There are many more filtered_bpm values than there are record messages. There are 2,977 filtered_bpm values and only 1,525 record messages to map them to.

If anybody can assist and explain hr messages to me that I will be extremely grateful!

Adrian.      

If anyone can help it will be greatly appreciated.

I am able to read the filtered_bpm, but I cannot work out how to map them to record message timestamps.

It would seem it should be described in section 6.2 Plugin Example (HR) of the FIT protocol document, but there's not enough information there to work out what is going on.

I'm currently trying to fathom out the CPP plug example, but it's also making my brain ache!

One of the things I am struggling with is what the event_timestamp_12 values are for? These are an array of 12 element, whereas the the filtered_bpm and event_timestamps are arrays with 8 elements!

In section 6.2 I mention above, it says that the event_timestamp are generated through Component Expansion - what is this?

I anyone can provide even partial answers to the above it will be a fantastic Christmas present!

Thanks for reading...