O channel Scale Factor calibration

Step 1. Connect to the calibration page of the web app

• Open the Calibration page of the Web Bluetooth App and connect to your power meter

• Assemble paddle with offset angle at 45 degrees Right Hand Twist. To check you have the angle setting correct, the angle reading displayed in the web-app should be close to +45 degrees when the paddle is placed into onto the jig (step 2).

• Measure and make note of the distance between the right blade tip and the LED. You will need to enter this value into the calibration spreadsheet in step 3.

Step 2. Place the paddle onto the calibration jig

• Place the paddle onto the calibration jig with the right blade face down on to the Blade Support

• The blade should be supported near its centre

• The shaft support should be approximately at the left hand position (+/- 20mm either side of the hand location, as specified in the configuration settings)

• The angle value displayed in the web app should be in the range +40 to +50 degrees. Adjust the shaft angle to achieve this as necessary.

Step 3. Measure and enter distances into the calibration spreadsheet

• Right tip to blade support: The distance from the right blade tip to the centre of the blade support.

• Right tip to shaft support: The distance from the right blade tip to the centre of the shaft support.

• Right tip to calibration weight: The distance from the right blade tip to the position where the calibration weight will be applied. It is helpful to mark this location with masking tape so when it comes time to applying the calibration weight you can hang the weight in the correct location. Apply the weight at the right hand position (+/- 20mm either side of the hand location, as specified in the configuration settings)

• Right tip to LED: The distance from the right blade tip to the LED

• Note, LED to Load Cell is a constant 0.0125 for Gen 3.1

Step 4. Record the zero-load outputs

With the paddle in position, but without any load applied, record the live output of channel O as shown in the Calibration page of the Web Bluetooth App and enter this into the first row of the calibration spreadsheet.

Read the paddle angle from the Web Bluetooth App and enter this into the first row as well.

The angle should be in the range +40 to +50 degrees. Adjust the shaft angle if necessary

Step 5. Apply weight to the shaft

• Hang a calibration weight off the shaft at the location measured in Step 3.

• Record the live outputs of channel O and the shaft angle in the second row of the spreadsheet.

• Enter the mass of the applied weight into the spreadsheet. Don't forget to include the weight of the rope, hook or bucket used to suspend the weight.

• Add another calibration weight to increase the load applied to the paddle.

You can extend the calibration spreadsheet to 3 or more points of calibration if you wish. To do this, repeat the steps above recording the O channel output, angle and calibration weight in a new row of the spreadsheet. Ensure the position of the calibration weight, the blade support and the shaft support remain the same for each point in the calibration process.

Step 6. Remove the calibration weights

Remove the calibration weights from the paddle and remove the paddle from the jig.

Step 7. Retrieve the Scale Factor from the spreadsheet

The calculated Scale Factor for the O channel is displayed within the plot (see example below):

The R^2 value should be close to 1. This indicates a good calibration.

Step 9. Set the Channel O Scale Factor

Set the scale factor by clicking on the word "Scale Factor" in the Web Bluetooth App. The Scale Factors should be multiplied by 1000 before being entered into the App. For example, if the Scale Factor is 0.0842, then the value '84' should be entered into the app. This value has been rounded up to three significant figures and does not include any decimal places

Congratulations! You have completed the O channel calibration. The Power Meter is now scale factor calibrated.