PowerTap Joule GPS User manual

PowerTap Joule™GPS
User Guide
Joule GPS is compatible with any ANT+TM
compatible power meter, speed sensor,
cadence sensor, or heart rate sensor.
WATTS
451 160
21 96
1:06:45
HR
MPH CAD
170 894
AV WATTS MX WATTS
RIDE TIME KJ
9:34 A 71º
380
INT

Joule GPS User Guide page 2
© 2012 Saris Cycling Group, Inc.
5253 Verona Road
Madison, WI 53711
All rights reserved. No part of this publication may be copied, photographed, reproduced, translated,
transmitted electronically or placed on digital media without the prior written consent of Saris Cycling
Group, Inc.
Trademarks
Saris Cycling Group, Inc.,PowerTap, and PowerTap logo, are all registered trademarks of Saris Cycling Group,
Inc. All other product, brand, or trade names used in this manual may be trademarks or registered trademarks
of their respective owners.
Modifications
Saris Cycling Group, Inc reserves the right to make improvements and/or updates to the products
described herein at any time without notice.
This device complies with part 15 of FCC Rules and Rss-210 of IC Rules. Operation is subjected to the following two conditions:
(1) This device may not cause harmful interference, and (2) This device must accept any interference received, including
interference that may cause undesired operation. The manufacturer is not responsible for any radio or tv interference caused
by unauthorized modifications to this equipment. Such modifications could void the user authority to operate the equipment.

CHAPTER
7. TRAINING 31
Workouts
Auto Interval
Countdown
8. DEVICE 36
Date & Time
Display
Memory
Altimeter
About
9. DATA & DOWNLOADS 42
Download
PowerAgent
10. FAQ & TROUBLESHOOTING 42
11. PRECAUTIONS 43
12. FEATURES LIST 44
TECHNICAL SPECIFICATIONS 45
13. WARRANTY 46
Appendix A, History Report Definitions 47
Appendix B, Error messages 53
Appendix C, Metrics 56
Appendix D, GPS Signals 58
TABLE OF CONTENTS
Joule GPS User Guide page 3
CHAPTER
1. STARTING OUT 4
Unpacking
Compatibility
Installation
Charging
2. OVERVIEW & SETUP 6
Dashboards
Main Menu
User
Sensor and Pairing
Buttons and Screen
3. DASHBOARDS 11
Dashboard 1,2,3: Metrics
Dashboard 4: Intervals
Dashboard 5: GPS Map
4. SENSORS 16
Sensors Overview
Define a Bike
Associating Sensors
Sensor Details
Calibration
5. NAVIGATION 22
Navigation Overview
Waypoints
Routes
GPS Status
Compass
6. HISTORY REPORTS 29
Overview
Reports

Joule GPS User Guide page 4
Thank you for purchasing the PowerTap Joule GPS. This user guide is just one of the resources to help
you understand all the features the Joule GPS has to offer.
Please visit www.PowerTap.com to:
• Learn more about the Joule GPS and the PowerTap system of products
• Register all PowerTap products and activate warranty
• View instructional videos
• Sign up for the PowerTap newsletter-your source for the latest news and technical updates from
PowerTap
PACKAGE CONTENTS:
PART QTY
Joule GPS computer 1
Heart rate strap (select models) 1
Stem/Handlebar mount 1
Front mount 1
Mount o-rings (2 sm, 2 lg) 4
Micro USB cable 1
CHAPTER 1: STARTING OUT
UNPACKING JOULE GPS
Joule GPS is compatible with any ANT+TM
power meter, heart rate sensor, cadence
sensor, speed sensor, or combination
speed/cadence sensor.
COMPATIBILITY

CHARGING
The Joule GPS is powered by energy from a rechargeable battery.
To charge the battery, plug into a computer or AC wall adapter
(#7060 not included). Typical battery charge lasts approximately
20 hours of operation.
Should the battery become completely discharged (no partial
charge remaining), plug the Joule GPS into a computer or AC wall
adapter, press the reset button on the back panel of the Joule
GPS, and the charging process should begin.
Joule GPS User Guide page 5
Micro-USB
USB
INT
INSTALLATION
Installing the PowerTap Joule GPS
OUT-FRONT MOUNT
INT
INT
O-Rings: Crisscross under
stem/handlebar, latch on hooks OR Zip tie around stem,
through slots
STEM/HANDLEBAR MOUNT
INT
INT
CHAPTER 1: STARTING OUT
INT

Main Menu
Ride
History
Sensors
Training
Navigation
User
Device
Back to Dashboard
9:34A71º
[ENTER]
Press & Hold 3 sec.
CHAPTER 2: JOULE GPS OVERVIEW & SETUP
DASHBOARDS
When the Joule GPS is turned on you are presented with one of 5 Dashboard screens (3 dashboards
displaying various Metrics, 1 dashboard displaying completed intervals, and 1 dashboard displaying the
GPS map). Pressing the Enter button allows you to scroll through all of the Dashboard screens. Dashboard
1, by default, is initially set to display 6 metric windows in the configurable area. Other screens can appear
between the Metric Dashboards and the GPS Map Dashboard, depending on what features you are using
(e.g. Training and Workouts, Navigating to a Waypoint, Following a Route, etc...).
• To view the Main Menu from any Dashboard, press and hold the ENTER button for 3 seconds.
• To return to the Dashboard from any Menu press and hold the ENTER button for 3 seconds.
Press any of the 4 buttons to turn the unit on
WATTS
--- ---
--- ---
0:00:00
HR
MPH CAD
0.0 0.0
AV WATTS MX WATTS
RIDE TIME KJ
9:34 A 71º
0
INT
Displays the Main Menu
Joule GPS User Guide page 6

CHAPTER 2: JOULE GPS OVERVIEW & SETUP
MAIN MENU
Enter the Main Menu to stop and save Rides, to review ride History, create/edit/select/pair Sensors, to use
the Training features and functions, to define individual Users, and configure the Device. Access to the main
menu can be gained while viewing any Dashboard by pressing and holding the Enter button. Use the (+)
and (-) buttons to scroll to your selection.
Joule GPS User Guide page 7
Main Menu
Ride
History
Sensors
Training
Navigation
User
Device
Back to Dashboard
9:34A71º
INT
[ENTER]
Press
& Hold 3 sec.
FROM DASHBOARD
TIP: Once you have entered the menu system (holding Enter button down for
3 seconds) the Interval button will act as the “back” button. Each time it is
pressed you return to the previous screen. Also, at the bottom of every menu
screen, there is a “Back to...” previous screen selection choice.
RIDE
Resume Ride
Stop and Save
Stop and Delete
HISTORY
Last Ride
Select a Ride
Report - Max
Report - Totals
SENSOR
Select a Bike
NEW BIKE
Add a Bike
Manual Zero
TRAINING
Workouts
Auto Interval
Countdown
NAVIGATION
Waypoints
Routes
GPS Status
Compass
USER
Select a User
NEW USER
Add a User
DEVICE
Date and Time
Display
Memory
Averages
Altimeter
About Joule

USER Multiple users can be stored
on each Joule GPS. (e.g. Jim, Bob,
Rachel can all share same device with
unique information). To add another user,
select Add a User, enter the name,
weight, height and date of birth for the
new user. If the training data is known
for this particular user it can be entered
now or enter it later, after a few rides.
CHAPTER 2: JOULE GPS OVERVIEW & SETUP
USER
The Joule GPS allows sharing of the same device with multiple users (i.e. Rachel, Jim, Bob). Each user can
have multiple bikes (e.g. TT bike, Road bike, MTB); each bike can have multiple sensors associated with it
(e.g. PowerTap, Cadence, HR strap, Speed). A default User is already defined within the Joule GPS. You can
either edit the settings associated with that User or create a new user by selecting Add a User.
Main Menu
Ride
History
Sensors
Training
Navigation
User
Device
Back to Dashboard
9:34A71º
User
Select a User
USER
Add a User
Back to Main Menu
9:34A
INT
FROM MAIN MENU
[ENTER]
Press
to scroll to User.
Press Name
Weight, lb
Height, in
Date of Birth
Gender
FTP
Power Zones
Heart Rate Zones
Joule GPS User Guide page 8
TIP: When editing within a data field, the ENTER button allows you to enter, then
move forward in the field; the INTERVAL button allows you to move backwards;
the PLUS/MINUS buttons allow you to pick a letter or number. Moving to the end
of the field and pressing ENTER twice exits the field.

CHAPTER 2: JOULE GPS OVERVIEW & SETUP
SENSORS & PAIRING
Pairing is a term used to describe the association of your Joule GPS with a particular sensor that is broadcasting an
ANT+TM signal (e.g. a PowerTap hub, a Heart Rate strap, a remote cadence sensor, a remote speed sensor, etc.).
Sensors can be shared between bikes (e.g. a heart rate strap). Each User can define multiple bikes. Each bike may
have one or more sensors associated with it. Use unique names when creating additional bikes. For example: Jim’s
Racing Bike, Jim’s MTB, My TT Bike, etc.
To add another bike:
· Select “Add a Bike,” enter a unique name and the weight of the bike.
· Associate the sensors with the bike. Make sure all the sensors are awake and
broadcasting (briefly spin PowerTap wheel, wear HR strap):
· Select “Pair All” to pair all sensors in range and awake (PowerTap hub, Heart
Rate strap). Sensors can also be paired individually by selecting each sensor.
Joule GPS User Guide page 9
TIP: The Joule pairs to sensor(s) closest to the device
first. Hold the Joule within 12” of PowerTap hub when
pairing in the presence of other sensors.
For more information on Sensors, see chapter 4
12” or 30cm
other sensors
INT
[ENTER]
Press & Hold
3 sec. to enter
Menus. Scroll
to Sensors;
Press •[ENTER];
Select “Add a Bike,”
Press •[ENTER] ;
FROM DASHBOARD
Main Menu
Ride
History
Sensors
Training
Navigation
User
Device
Back to Dashboard
9:34A71º
Sensors
Select a Bike
Jims RB
Add a Bike
Manual Zero
Back to Main Menu
9:34A
NewBike2
Name
NewBike2
Weight
0.0
Pair All
Power Sensor
None
Cadence Sensor
None
Speed/Combo
None
Heart Rate Sensor
None
RU Sensor
None
Delete Bike
Back to Sensors
9:34A

WATTS
451 160
21 96
1:06:45
HR
MPH CAD
170 894
AV WATTS MX WATTS
RIDE TIME KJ
9:34 A 71º
380
INT
Joule GPS User Guide page 10
BUTTONS and SCREEN
There are three buttons on the sides of the Joule GPS and one large button below the screen. The
screen is divided into 3 display areas. The top area, Title Bar, displays time, temperature, compass, and
battery level. The large middle section, displays user-selected metrics and can be configured to show 3
to 6 windows. The lower section shows complimentary metrics associated with the highlighted metric.
CHAPTER 2: JOULE GPS OVERVIEW & SETUP
Highlighted
Metric,
Complimentary
Metrics
Micro-USB port
Ride Time or Clock
Temperature
North Arrow and GPS Signal Lock Indicator
Battery Level
[ENTER] button * Press once to move through each Dashboard
* Hold for 3 seconds - Go to Menu
* In Menus, press to selects menu item
* In Menus, hold for 3 seconds to go to Dashboard
* Shifts selected metric or “highlight box”
to the right and down
* Hold for 3 seconds - Begins metric rotation
* Shifts selected metric or “highlight box”
to the left and up
* Press to mark intervals
* Hold for 3 seconds - Go to Interval view
* Hold for 3 seconds - Go to Ride view
* In Menus, press to go back to previous screen
* Press together to put the Joule to sleep
* Press together to “find” sensors that may have
been lost or were not awake when the Joule
powered up.
[PLUS] button
[MINUS] button
[PLUS] button
[MINUS] button
[INTERVAL] button
[INTERVAL] button
BUTTONS FUNCTION
[PLUS] button

Joule GPS User Guide page 11
CHAPTER 3: DASHBOARDS
DASHBOARD 1
METRIC 1
METRIC 1
METRIC 2 METRIC 3
METRIC 2 METRIC 3
WATTS WATTS
451 160
21 96
1:06:45
HR
HR
MPH
MPH
CAD
CAD
170 894
AV WATTS MX WATTS
AV WATTS MX WATTS
AV HR MX HR
RIDE TIME
RIDE TIME
KJ
KJ
9:34A71º
Selected metric
highlights gray Selected Metric
Detail View:
2 Complimentary Metrics
Detail Views
AA B
B
AV MPH MX MPH
AV CAD MX CAD
MILES Kilojoules
KJ/HR TSS
C
C
D
D
E
E
F
F
380
Press • [ENTER] to
advance through
Dashboards
INT
[ENTER]
TIP : All dashboards are fully customizable from 3-6 metric windows
per dashboard (See Chapter 7) and any of 23 metrics to choose
from. See Appendix C for full list of metrics.
DASHBOARD 1
The Dashboards display various metrics, summaries and navigation information that can be easily customized.
When a new metric is highlighted, the detailed view changes to show the related complimentary metrics.

Joule GPS User Guide page 12
DASHBOARD 2
Dashboards can be customized to display from 3 to 6 metric windows. The example on previous page
displayed 6. The example below, Dashboard 2, displays 4 metric windows. Each window can display any of
23 metrics, plus even more related/complimentary metrics. See Appendix C for a full list of metrics.
CHAPTER 3: DASHBOARDS
METRIC 2 METRIC 3
Detail View:
2 Complimentary Metrics
DASHBOARD 2
1:06:45
RIDE TIME
21
MPH
WATTS
132 185
AV HR MX HR
9:34A71º
A
CD
451 160
HR
B
METRIC 1
Selected metric
highlights gray
METRIC 1 METRIC 2 METRIC 3
WATTS
HR
MPH
AV WATTS MX WATTS
AV HR MX HR
RIDE TIME
Selected Metric Detail Views
A
B
AV MPH MX MPH
Total Miles Kilojoules
C
D
Press • [ENTER] to
advance through
Dashboards
INT
[ENTER]

Joule GPS User Guide page 13
DASHBOARD 3
Dashboard 3 is configured to display 3 metric windows (default configuration). Press the Plus (+) or Minus
(-) button to highlight a different Metric. See Appendix C for a full list of metrics.
CHAPTER 3: DASHBOARDS
Detail View:
2 Complimentary Metrics
1:06:45
RIDE TIME
25
SPD GRADE
9:34A71º
A
B C
26.00 380
MILES KJ
DASHBOARD 3
METRIC 1
Selected metric
highlights gray
METRIC 1 METRIC 2 METRIC 3
SPEED
GRADE
MILES KJ
AV MPH MX WATTS
RIDE TIME
Selected Metric Detail Views
A
B
AV GRADE FT GAIN
C
Press • [ENTER] to
advance through
Dashboards
INT
[ENTER]
METRIC 2 METRIC 3
5%
TIP : By holding down the + [PLUS] button for 3
seconds, any of the three related metrics can be
rotated into the primary dashboard metric position.
For example: To see total Distance traveled as the
main metric, instead of Ride Time, press the [PLUS]
key until the highlighted metric is Ride Time. Next,
hold the [PLUS] key down for 3 seconds, continue
holding the button down while the metrics are
rotating. release the button when the desired metric
is the primary or highlighted metric.

Joule GPS User Guide page 14
CHAPTER 3: DASHBOARDS
INTERVALS SUMMARY
Interval Dashboard contains
a summary of your Intervals.
Press • [ENTER] to
advance to the Intervals
Dashboard.
INT
[ENTER]
Intervals
2160w0:10:14
80kj 1.25mi
9:34A71º
Interval number
Current interval at top
Interval time
Interval distance 1285w0:05:02
101kj 2.65mi
0192w0:12:32
221kj 2.65mi
Avg. Power
Total kilojoules
If power data is not available,
Speed and HR are displayed:
Avg. Heart Rate Avg. Speed
WATTS
176 2
PWR ZONE
9:34A71º
WATTS
451 5
PWR ZONE
9:34AINT 2
Interval marker
(replaces Temperature)
INTERVALS DASHBOARD
Intervals are useful for viewing ride data specific to a section of a ride, such as a hill or other period of high intensity
riding. Press the Interval button to begin an Interval. Press it again to end the current interval and begin another interval.
Press and Hold for 3 seconds to go from Ride View to Interval View; Press and Hold again to return to Ride View.
[INTERVAL]
INT
Press & Hold
3 sec. to go to
Interval View
Press & Hold
3 sec. to go
back to Ride
View
RIDE VIEW INTERVAL VIEW
Metrics displayed are for current interval
ENTIRE RIDE INTERVAL 2
INTERVAL 1
UP TO 99 INTERVALS
Metrics displayed are for overall ride
10:12:32
2.65mi146
15.2mph

Joule GPS User Guide page 15
CHAPTER 3: DASHBOARDS
NAVIGATION or GPS MAP DASHBOARD
The Dashboard associated with Navigation is a GPS map with a current position indicator and a rendering of
the path ridden to that point in time. The screen may also display waypoints (), interval markers (), and a
pacing icon (), depending upon which navigation feature is being used. To zoom the map in or out, press the
PLUS (+) and MINUS (-) buttons. Various zoom levels range from 75 meters to 80 kilometers (250 ft to 50
miles). Two configurable metric windows display at the top of the screen. When following a route, information
related to total route distance or distance to the next turn appears above the metrics.
Press • [ENTER] to
advance through
Dashboards, to the
Map screen.
INT
[ENTER]
GPS MAP Dashboard
9:34A71º
WATTS
184 96
CAD
01
2
Ofce
Home
5 mi
Metric of the selected
Category is shown
North arrow (compass)
Waypoints
Zoom level
Position indicator
Intervals
Start
Press + [PLUS] to zoom in
Press - [MINUS] to zoom out
Satellite Reception Indicator.
The status bars appear while the
Joule GPS is progressing toward a
full fix on your current position,
using the GPS Satellites orbitting
above the Earth. Each solid bar
represents one Satellite signal lock.
A full position fix occurs once the
device has locked on 4 to 5
TIP: The GPS signal locking process can take anywhere from less than a
minute to several minutes, depending on weather, environmental
conditions and/or when the last time the device was powered up.
See Appendix D for detailed information on GPS signals.

CHAPTER 4: SENSORS
SENSOR OVERVIEW
The Sensor section of the Joule GPS menu is the gateway to all bicycle and sensor associations. In this area you can
define and pair various sensors (e.g. power meter, heart rate strap, speed, cadence, PowerCal, PowerBeam, etc.). You
can create a “bike” with a specific group of sensors. Or, if you have already created a bike or two, you can select
which bike description to “use” (i.e. which bike you are about to ride), or which bike description to “edit.”You can also
get access to utilities related to calibration, such as calibrating the torque of a particular power meter or calibrating the
Resistance Unit (RU) of a PowerBeam indoor trainer.
Joule GPS User Guide page 16
INT
[ENTER]
Press & Hold
3 sec. to enter
Menus. Scroll
to Sensors;
Press •[ENTER];
Scroll to the bike
to Use or Edit;
Select the bike
Press •[ENTER];
Press +[PLUS] for
Use, -[MINUS] for Edit.
FROM DASHBOARD
Main Menu
Ride
History
Sensors
Training
Navigation
User
Device
Back to Dashboard
9:34A71º
Sensors
Select a Bike
Bike1
Bike2
Add a Bike
Manual Zero
Back to Main Menu
9:34A
Sensors
Select a Bike
Bike1
Bike2
Add a Bike
Manual Zero
Back to Main Menu
9:34A
Bike1
selected
Edit Use

Bike1
Name
Bike1
Weight
17.0
Pair All
Power Sensor
Power1
Cadence Sensor
None
Speed/Combo
None
Heart Rate Sensor
HeartRate1
RU Sensor
None
Delete Bike
Back to Sensors
9:34A
INT
[ENTER]
Press & Hold
3 sec. to enter
Menus. Scroll
to Sensors;
Press •[ENTER];
Scroll to either an
existing bike to edit
or to “Add a Bike” to
create a new bike.
Press •[ENTER]
FROM DASHBOARD
Main Menu
Ride
History
Sensors
Training
Navigation
User
Device
Back to Dashboard
9:34A71º
CHAPTER 4: SENSORS
Joule GPS User Guide page 17
Sensors
9:34A
Select a Bike
Bike1
Bike2
Add a Bike
Manual Zero
Back to Main Menu
Sensors
9:34A
Select a Bike
Bike1
Bike2
Add a Bike
Manual Zero
Back to Main Menu
DEFINING A BIKE
Display the bike definition screen either by selecting an existing bike to edit or by adding a new bike. The bike definition
screen contains the name, weight of the bike, and links to any associated sensors. Also, the bike definition can be
deleted here.
Bike1
selected
Edit Use
Define a New Bike
Activate Existing Bike
Edit an Existing Bike
Manual Zero
ACTION OPTION
Select “Add a Bike.” Edit the default name, weight, and pair the sensors, either using Pair All or individually.
Select the bike name, choose Use (press the +[PLUS] button), and the bike will be activated (checkmark near bike
name). Hold the [ENTER] button down for 3 seconds to return to dashboard or back out of menus to dashboard
using the [INTERVAL] button.
Select the bike name, choose Edit (press the -[MINUS] button), and the bike defintion screen will appear.
A shortcut for power meter calibration. See information later in this chapter.

Bike1
Name
Bike1
Weight
17.0
Pair All
Power Sensor
Power1
Cadence Sensor
None
Speed/Combo
None
Heart Rate Sensor
HeartRate1
RU Sensor
None
Delete Bike
Back to Sensors
9:34A
Power Sensor
Activate Sensor
Start Pairing
Name
g3CarbonC45
Sensor ID
11484
Circumference, mm
2096
Auto Zero
Yes
Delete Sensor
Manual Zero
Back to Bike
9:34A
Bike1
Name
Bike1
Weight
17.0
Pair All
Power Sensor
Power1
Cadence Sensor
None
Speed/Combo
None
Heart Rate Sensor
HeartRate1
RU Sensor
None
Delete Bike
Back to Sensors
9:34A
CHAPTER 4: SENSORS
Joule GPS User Guide page 18
ASSOCIATING SENSORS
For sensor association, there are two options: Pair All or Pair Individually.
PAIRING
Pair All
Pair Individually
Link Named Sensor
OPTION DESCRIPTION
Select “Pair All” when setting up a new bike. The Joule GPS will scan for all sensors awake and present. Upon finding a
sensor the Joule will display the ID, and ask to use the sensor or not. Selecting Yes (press the +[PLUS] button), will link
the sensor to the new bike definition. The Joule will continue to scan for other sensor types. Select No (press the -[MINUS]
button) and the Joule will continue to scan for more of the same sensor type before looking for another type of sensor.
Also, Pair All will use the next available default sensor name for each sensor type linked to a bike definition.
To pair sensors individually, scroll to each sensor, using the +[PLUS] or -[MINUS] button. Selecting the sensor name will
display a menu of sensor names (the name will “<none>” indicates no sensor has been linked to the bike definition).
Select “<new sensor>” to scan for an awake and present sensor. When the Joule finds a sensor of this type it will
display the ID, and ask to use the sensor or not. Selecting Yes (pressing the +[PLUS] button), will link the sensor with the
new bike definition. Select No (pressing the -[MINUS] button) and the Joule will continue to scan for the same sensor type.
Scroll to and select the sensor name. A menu of default or edited sensor names will appear. Scroll to a predefined sensor,
select it. You will be asked to Use it or Edit it. Selecting “Use” will link the sensor to the bike definition.
PAIR INDIVIDUALLYPAIR ALL
g2MTB29
g3CarbonC45
<None>
<New Sensor>

Power Sensor
Activate Sensor
Start Pairing
Name
Power2
Sensor ID
2484
Circumference, mm
2096
Auto Zero
Yes
Delete Sensor
Manual Zero
Back to Bike
9:34A
Heart Rate Sensor
Activate Sensor
Start Pairing
Name
HeartRate1
Sensor ID
38742
PowerCal
Yes/No
Delete Sensor
Back to Bike
9:34A
Speed/Combo
Activate Sensor
Start Pairing
Name
Speed1
Sensor ID
4848
Type
Combo
Circumference, mm
2096
Delete Sensor
Back to Bike
9:34A
Cadence Sensor
Activate Sensor
Start Pairing
Name
Cadence1
Sensor ID
5624
Delete Sensor
Back to Bike
9:34A
RU Sensor
Activate Sensor
Start Pairing
Name
RU1
Sensor ID
130
Delete Sensor
Calibrate
Back to Bike
9:34A
CHAPTER 4: SENSORS
Joule GPS User Guide page 19
SENSOR TYPE DETAILS
Once you have navigated to the Sensor detail screen, you will notice each sensor type has some attributes that are shared and
some that are unique to the sensor. Below are the detail screens for the various sensors supported.
Overview
Power
Heart Rate
Speed/Combo
Cadence
RU
SENSOR DISCUSSION
For each type of sensor the detail screen displays items common to all sensors, including activation and pairing functions, an
editable name and an editiable I.D.. If you know the I.D. of a particular sensor you can manually enter it into the I.D. field.
Otherwise, the “Start Pairing” option will fill it in automatically when pairing completes.
If your power meter is a hub-based power meter, like a PowerTap, the wheel circumference can be entered here. The default
wheel size of 2096mm represents a 700x23 wheel. Ignore circumference if your power meter is not hub-based. Auto Zero
and Manual Zero options refer to calibration and are discussed in the next pages.
The PowerCal option is automatically set during the paring process when it is determined the HR strap is a PowerCal.
The type of speed sensor is determined automatically during the pairing process (either a combination speed and cadence
sensor or a speed-only sensor). Enter the circumference of your wheel. The default wheel size is 2096 mm (700x23).
No additional options.
Resistance Unit or RU is associated with CycleOps PowerBeam trainers and indoor cycles.

Joule GPS User Guide page 20
TIP: The accuracy of any power meter is dependant on many variables, especially temperature. Fluxuations in temperature
affect the internal strain guages, which affects the reported torque value (power is calculated from torque). The PowerTap
Auto Zero feature continually adjusts the calibration of your device, compensating, in real time, for environmental factors like
temperature, assuring that you have the most accurate power data throughout your ride.
Power Sensor
Activate Sensor
Start Pairing
Name
Power2
Sensor ID
2484
Circumference, mm
2096
Auto Zero
On/Off
Delete Sensor
Manual Zero
Back to Bike
9:34A
CHAPTER 4: SENSORS
CALIBRATION, AUTO and MANUAL ZERO
There are many environmental factors that can affect the accuracy of a power meter. Temperature, humidity, and circuit
resistance are part of the measurement, but none of them remain constant while riding. A power meter must account for those
changes to remain accurate. Auto-zero recalibrates the power meter over and over during a ride to keep the measurements
from drifting. Use the Auto or Manual Zero options in the Power Sensor screen to calibrate your power meter, assuring you are
getting the most accurate power data all time.
Power2
Manual Zero
Torque RAW
<Value>
Torque Offset
<Value>
Firmware Version
45
Back to Sensor
9:34AAuto Zero
Manual Zero
On or Off. Typically, always On. The Auto Zero
function follows the same steps outlined for
Manual Zero but does it continually during the
ride, whenever the bike is coasting for 4 or
more seconds. If your bike is a fixed-geared
or track bicycle you may consider turning
Auto Zero off.
Calibrating or “zeroing the torque” refers to the
process of resetting the Torque Offset value of
the physical torque tube (where the internal
strain guages actually measure wheel torque).
1) Make sure the power meter is awake and
communicating with the Joule. Make sure
the bike is sitting still, no feet on pedals, no
tension in chain.
2) Select Manual Zero on Power Sensor screen.
The Calbration screen will appear. Torque
RAW should be 0.The last saved Torque
Offset is displayed. The value is typically
500-524 in-lbs.
3) Select Manual Zero on Calibration Screen.
The Torque Offset value will update with the
torque tube calibration value, given the
current environmental conditions.