Zero Torque With Ibike

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Sarg
Posts: 16
Joined: Sat Jun 07, 2008 5:57 pm

Zero Torque With Ibike

Post by Sarg » Sun Apr 21, 2013 11:55 am

How do I zero torque on a powertap g3 hub using the iBike Newton? I have searched the forum but did not find any instructions on how to do this with the Newton. Any help would be greatly appreciated.

Thanks!

Davis6022
Posts: 38
Joined: Mon Mar 11, 2013 10:03 am

Re: Zero Torque With Ibike

Post by Davis6022 » Wed May 08, 2013 5:47 pm

Ever get an answer?

FirmwareGuy
Posts: 18
Joined: Wed Mar 06, 2013 9:26 am

Re: Zero Torque With Ibike

Post by FirmwareGuy » Fri May 10, 2013 7:33 am

There is a command in the Setup Screens called "PCal". When you are paired with the powertap, you should be able to use that command to zero the torque. When you use this command to zero the torque, the bike should not be moving and you should not have your feet on the pedals.

Sarg
Posts: 16
Joined: Sat Jun 07, 2008 5:57 pm

Re: Zero Torque With Ibike

Post by Sarg » Fri May 10, 2013 8:13 am

Thanks for the information! I looked through the manual and did not see any instructions on how to do this.

FirmwareGuy
Posts: 18
Joined: Wed Mar 06, 2013 9:26 am

Re: Zero Torque With Ibike

Post by FirmwareGuy » Tue May 14, 2013 7:32 am

I am currently coordinating with the manual writer to get the documentation updated to include information about the PCal command. Hopefully, the online manual will be updated soon.

FirmwareGuy
Posts: 18
Joined: Wed Mar 06, 2013 9:26 am

Re: Zero Torque With Ibike

Post by FirmwareGuy » Tue May 14, 2013 3:55 pm

The PCal command is used to trigger the calibration in DFPM sensors that are paired with the Newton. This command will only be available in the Setup menu of the Newton if a DFPM sensor is currently paired with the Newton. Use the following steps to perform the DFPM Sensor Calibration:

1. Stop the bicycle.
2. Take your feet off the pedals
3. Enter Setup and use the buttons to move through the menu until you reach the screen with "PCAL" in the middle and a number in the bottom of the display.
4. Press the center button. This will cause the bottom display to flash.
5. Press the UP or DOWN arrow on the display. This will cause the word "Start" to flash in the bottom display.
6. With the "Start" flashing, press the center button. This will Trigger the start of the calibration process.
7. The word "Proc" may flash briefly in the bottom display while the calibration command is being processed by the DFPM.
8. Upon successful completion of calibration by the DFPM, the bottom display will return to a flashing number. Pressing the center button will then terminate the process.
9. If the DFPM reports an error back to the Newton, the work "Fail" will flash in the bottom display. The user could then use the UP or DOWN arrow to change back to "Start" and reattempt the calibration.

The only caveat that should be pointed out is when the DFPM being calibrated is a "Crank-Torque-Frequency" type device like the SRM power sensor. For these devices, the number displayed in step 8 may change values while it is flashing. The user should wait until the number stabilizes before pressing the center button to "lock in" the calibration value and terminate the calibration sequence. For SRM sensors, this number is used in the power calculations in the Newton, and it is important that the "stable" number be captured. Failure to do so could result in bad power numbers being calculated from the power sensor data.

Davis6022
Posts: 38
Joined: Mon Mar 11, 2013 10:03 am

Re: Zero Torque With Ibike

Post by Davis6022 » Thu May 16, 2013 9:05 am

Thank you FirmwareGuy for posting the directions for using the Pcal command. Some questions and suggestions:

1. Is it possible to change Step 5 so that you press the center button again instead of the up or down arrow? Or to state something like "Press Up to Start Cal"? I thought I had the procedure down yesterday when I went for a ride, but apparently I missed Step 5 as it wasn't intuitively obvious to me that this was the next step.

2. I noticed in Isaac that if you don't pair your DFPM with Newton to read P-in, and you merge your Garmin .fit file (which was paired with the DFPM) with the .ibr file, the DFPM Fit in the calibration command doesn't appear to work properly even though it is enabled. But, if you do pair your DFPM with Newton to read P-in, the DFPM Fit command works great with the .ibr file itself. I don't know if the DFPM Fit command was intended to work with merged files, but I suggest a warning be given in Isaac that this procedure does not work for merged files.

3. When the Newton is paired with the DFPM to read P-in, a dot with a circle appears on the left hand side of the middle field on the Newton. When I'm riding, there is either an arrow head on top or below the dot/circle. From what I can tell, this is telling me my current power is either above or below my average power for the ride. Is this correct?

Mike

FirmwareGuy
Posts: 18
Joined: Wed Mar 06, 2013 9:26 am

Re: Zero Torque With Ibike

Post by FirmwareGuy » Thu May 16, 2013 10:02 am

Hi Mike,

I used to have the word "idle" displayed in the bottom display instead of the number as in indication that you needed to press up or down to actually start the process. This was years ago. It was decided to display the flashing number instead to try to relate information about the calibration values that may be valid for certain types of power meters. The "subtle" thing here that we try to implement consistently in the setup menus is that when a display is flashing, the up/down arrows are used to change the value and the center button is used to "lock it in" or "execute". I agree with you that it seems like one extra step in the process. However, it gives a user the ability to abort the calibration in the event that they get into by accident. In other words, if the rider is not careful, and happens to have his finger bounce on the center button, it could trigger a zero calibration operation when the user is not really ready to trigger it. For what it's worth, that's the reasoning behind it.

I'll have to have the guy responsible for the Isaac software respond to your second question as I am not an expert on what is going on behind the scenes in Isaac.

As far as the arrows go in the middle display, you are correct in your assumption. The arrows are trying to show that your current power is either above or below you average power for the ride.

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