Any way to zero out PowerTap data files?

[DennistheMennis]

Hi folks:

I was just wondering. If I don't zero out my PowerTap CPU before a ride, and later discover the ride "Activity" is reading too high in PowerAgent, is there a way to export that ride's power data to a CSV file (I've done this already), then open up the CSV data file (I use Excel) and figure out how much the Watt readings are off?

I assumed my CSV file would simply show something obvious like the smallest Watts is "23W" or "-57W" or something. But that doesn't seem to be the case. My file shows "-1" for the lowest Watt readings after I sort by the "Watts" column, so it looks roughly correct. But I suspect it isn't.

One thing I noticed is that the " Torq (N-m)" column never reads below "1.469" which seems very wrong. And that the corresponding Watts for all of those "1.469" samples vary between "-1" and "15". That might mean something...perhaps I need to lower my Watts by "15" throughout?

Anyway, thought one of you might know. Thanks,

[daveryanwyoming]

Yeah, you can correct PT files after the fact if there was a consistent torque zero error.

There's a detailed description of the procedure on the wattage group FAQs: http://groups.google.com/group/wattage/web/ptnonzero

You'll need to apply to the group to get access to that page, but it's free and simple to answer a few bike questions.

-Dave

[DennistheMennis]

Thank you sir! Will do that ASAP!

[ashclocip]

Glad to read such a nice piece of information.
This is exciting news.
what a great info, thanks.

[DennistheMennis]

So, thanks again! I did note one item that the instructions didn't mention:

If you have trouble importing the edited activity "CSV" file into PowerAgent, go back to the CSV file and set the format of the "Watts" column cells to "0" decimals (integers only, no decimals). That solved it for me.