PowerTap Files

Discussion in 'Power Training' started by MY02_STi, Jan 17, 2007.

  1. MY02_STi

    MY02_STi New Member

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    Can someone explain how PowerTap allocate files/memory :confused:

    Say for arguments sake, I do 2 workouts on one day without downloading the files. Will these appear as separate workouts provided I remove the CPU from the harness between each workout ?

    What I'm concerned about is that on some of our long group rides, say 5 to 6 hours, we will maybe have 2 stops of about 10 minutes during which time the CPU will go into sleep mode, so if I press a button on the CPU recording will recommence, but as part of the original file ?? or as a separate file ??

    Basically, does removing the CPU from the harness determine the 'end' of the workout/session :confused:

    Any advice would be appreciated :)
     
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  2. Woofer

    Woofer New Member

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    It depends on what CPU and what software you are using to download the data. The current generation CPU's have a real time clock and keep track of when you ride (start/stop time) when stops are greater than N minutes but I forget what N is. If you use the PowerTap software to download it ignores the start/stop times. If you use CyclingPeaks it uses the start/stop times.
     
  3. F1_Fan

    F1_Fan New Member

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    "N" is set through the PT configuration options... it's something like 1, 2, 4, 8,... minutes
     
  4. Steve_B

    Steve_B New Member

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    The PT will always consider everything in the memory as one long file. So unless you run out of memory or clear it, it all comes out in one big stream. The end of the session is technically when you clear the memory or fill it because up to that point, it will just continue to record data. You could even download and put the computer back on the bike and append more data to the ride.

    There is a time and date stamp associated with each data point within the PT computer. Using this, WKO+ will consider anything with a gap of more than 30 minutes of no activity (someone correct me on the time period if I'm wrong) as a seperate file.

    Gaps of 10 minutes will probably not cause it to do anything different. In WKO+, you'll see a little gap but it doesn't affect the numbers.

    If a gap should go longer (again, I believe it's the 30 minute point) and you download to WKO+, the download window will show two (or more) individual files and you simply drag them to the proper date on the calendar. If you drag more than one file to the same date, they will be appended together by time of day. If the downloads come from seperate days, it's up to you to assign them to the correct date in the calendar but other than that, no worries.

    My downloads from my bike commute have the morning and evening data as seperate files, ~8 hours apart. I just drag them to the same date in the calendar in WKO and treat them as one workout.

    I don't know what Power Agent and other software programs do.

    Bottom line, no sweat. Even if you take an extend break, you can merge stuff together pretty easily, at least in WKO+.
     
  5. Alex Simmons

    Alex Simmons Member

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    Yes, WKO+ will show separate files when a ride has a long period of inactivity. I'm also not sure the precise inactivity duration (20-30 mins) it uses to define when a file shows as two separate rides.

    Note: While you can programme the time before the CPU will go to sleep (which is simply a battery save thing), this is unrelated to the file split/inactivity duration feature - I don't believe this inactivity duration feature is user programmable.

    No big deal though - if it splits 'em in the WKO download and you want them together in WKO as one file (OK - you had a longish coffee stop), then just drag both to same day. WKO will mash 'em together quick smart.*

    However, if you want to WKO to show and record them as two separate workouts files e.g. a morning and evening workout (which is a good idea BTW - will explain in a minute) then drag the first file to the right day in the calendar, which will open it as a new workout. Save and then go back to calendar page and right click on that same calendar day and select option to create a new workout for that same day - it will open up another blank workout file. Then drag the second download file to the new blank workout. It will then save 2 workouts separately.

    Why would you bother to do that?

    Well the Mean Maximal Power calculations ignore the time gaps in ride files.

    So for example, let's say in the morning you rode 50 mins of L2, then finished with 10 min of L4, no warm down. Then in the evening you started with 10 min of L4, then only did L2 from there.

    If you put these two rides into same wko file, then the 20 min MMP would be the two separate 10 min L4s considered contiguously, even though they may have 8 or more hours of inactivity in between!

    Now while the above example is hypothetical, I have seen MMPs for some longer durations (e.g. 45+ minutes) impacted by this (e.g. morning ride/afternoon crit race). Clearly that is not a real MMP.


    * Careful if you use different CPUs though. If the clocks are out that can cause problems (I do for different bikes if I happen to swap them - think Floyd in the tour when he changed bikes - for me it can be road bike warm up / track bike race or a trip away where I need the extra memory of a 2nd CPU).
     
  6. MY02_STi

    MY02_STi New Member

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    Thanks guys :D
     
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