Ttr ro ou ub bl le es sh ho oo ot tiin ng g – PowerTap SL User Manual
Page 31
31
L
Liin
nk
k S
So
offttw
wa
arre
e
T
Th
he
e ffo
ollllo
ow
wiin
ng
g a
arre
e s
so
om
me
e p
prro
ob
blle
em
ms
s y
yo
ou
u m
miig
gh
htt h
ha
av
ve
e w
wh
he
en
n iin
ns
stta
alllliin
ng
g a
an
nd
d s
se
ettttiin
ng
g u
up
p y
yo
ou
urr L
Liin
nk
k S
So
offttw
wa
arre
e.. T
Th
hiis
s lliis
stt w
wiillll b
be
e
e
ev
vo
ollv
viin
ng
g,, s
so
o p
plle
ea
as
se
e v
viis
siitt o
ou
urr w
we
eb
b s
siitte
e ffo
orr a
a c
cu
urrrre
en
ntt ttrro
ou
ub
blle
es
sh
ho
oo
ottiin
ng
g g
gu
uiid
de
e:: h
httttp
p::////w
ww
ww
w..c
cy
yc
clle
e--o
op
ps
s..c
co
om
m.. IIff y
yo
ou
urr p
prro
ob
blle
em
m
iis
s n
no
ott a
ad
dd
drre
es
ss
se
ed
d h
he
erre
e y
yo
ou
u c
ca
an
n c
ca
allll C
Cu
us
stto
om
me
err S
Se
errv
viic
ce
e a
att 1
1--8
80
00
0--7
78
83
3--7
72
25
57
7..
G
Ge
en
ne
erra
all L
Liin
nk
k T
Trro
ou
ub
blle
e S
Sh
ho
oo
ottiin
ng
g
R
Ra
aw
w D
Da
atta
a F
Fiille
es
s
Some of the more sneaky of you will try calculating power/heart rate for just one ride to see how cardiac fatigue
might be affecting your ride. You'll do this by running the .CSV file in Excel and calculating the factor for each
record. Then you'll replace the calculated column for the existing, say, Torque column. This is very naughty. You
need to know that as soon as you import that data into your database, it will affect your entire database history until
you delete the ride. If you want to try such experiments, it's best to import such adulterated data into a separate
rider name.
D
Da
atta
ab
ba
as
se
e M
Ma
an
na
ag
ge
em
me
en
ntt
As long as you are keeping all the raw data (.CSV) files, you can always start over by importing the files again.
Remember that you can always delete a ride and rider from the database to start over.
D
Da
atta
a D
Diiffffe
erre
en
nc
ce
es
s B
Be
ettw
we
ee
en
n L
Liin
nk
k a
an
nd
d P
Po
ow
we
errT
Ta
ap
p C
Co
om
mp
pu
utte
err
There are two issues here, data inconsistency and time differences. First the display on the PowerTap CPU has a 3
sample running average. This 3 sample average is used for displaying averages
and maximums on the PowerTap computer display. This reduces the "jumpiness" of the numbers and makes it easi-
er to use while riding.
The data saved for download is raw, exactly as it is sent to the hub.
In the CPU set up mode (press MODE and SELECT buttons simultaneously until you see 'SETUP') you can select 1
or 2 sample recording. If you select 1 the data is sent to the CPU from the hub at 1-second intervals. The 1-sec-
ond mode will save every data point sent from the hub. If you select 2 the data is sent to the CPU at 2-second
intervals. The 2-second mode will in effect save only every other data point sent from the hub. Therefore in the 2-
second mode Maximums can be missed.
So between the averaging and the save rate the data download will be different. In the 1-second mode the down-
load data is always most accurate.
The second issue is time differences. The data points used for display on the CPU may not coincide perfectly with
what is stored to memory. There can be up to a 1-sample (or 1-second) loss at the start and stop of a download
file. If the CPU is in 2-second mode this max time error (2-seconds at the start and/or stop) can be as much as 4-
seconds off.
The individual raw data records written to memory are extremely accurate. In fact the data has been proven in lab-
oratory testing to be accurate to +/- 1.5%. This means the data downloaded to the Link accurately represents what
was happening on your bike second by second. How we repackage the data, to make it useable does not affect or
detract from its accuracy - it's just making it more user friendly.
T
TR
RO
OU
UB
BL
LE
ES
SH
HO
OO
OT
TIIN
NG
G