TL0103004 - RPM sensor
This sensor is designed to be used with nitro motor. For sensored electric motor, please check TL0103002 - Motor sensor breakout
Description
RPM sensor is used for measuring RPM of any rotating axle. It is also used as speed sensor by giving drive ratio values during configuration.
Package doesn't include any brackets for installation and this is due to the reason that it is impossible to design universal bracket to fit all cars. Please check our 3D model library if there is proper bracket available for your car. Library is available at https://github.com/testlogger/tl-collector-3d-print-files
Installation
Magnets
- Package includes two magnets which needs to be installed on the rotating axle.
- Install the magnet to magnet ring or glue to rotating axle.
It is very important that magnet is installed correct way. Otherwise sensor will not detect the change in magnetic field.
Sensor
- Install sensor very close to the magnet. The airgap is very important to be small as possible. 1-2mm is recommended
- Package included extra shrink tube to fix sensor to bracket
Configuration
In normal situation Basic settings should be enough to configure the channel. Use Advanced parameters only if you know what you are doing.
Pinion and spur gear are important to set correctly as well if RPM/speed is measured from motor. These are set in General settings of the config. See Device configuration
Parameters for speed input RPM
| Parameter | Visibility | Type | Default value | Description |
|---|---|---|---|---|
| Enable | Basic | Boolean | yes | Parameter is used to enable the sensor for logging. Sensor is enabled if value is yes. |
| Radius | Basic | Decimal | 1 | Tire radius in meters. For example in 1/8th scale offroad good value is 0.052, so 5.2cm. Please notice! that this is radius and not diameter! |
| Internal ratio | Basic | Decimal | 1 | If speed is measured from the motor or from center differential, then typically this value needs to be set according to chassis specification. For example in AE RC8B3.2e the RPM can be measured from the motor. If the differential pinion is 13T and ring gear is 44T, then internal drive ratio and value for this parameter is 44/13 = 3.38 |
| Magnets | Basic | Integer | 1 | Here is defined how many magnets there is per rotation. With the package you will have two magnets. |
| Name | Advanced | String | Speed Motor | Channel name to be used in the exported data file. Data file will have own channel for all three dimensions and system will add the axis identifier after the channel name |
| Type | Advanced | Option | Motor RPM | Selection if this input is used for outdrive speed measurement or for RPM measurement. If Motor RPM is selected, then data file will have RPM and speed channel. If option General is used, then only speed channel will be visible. Please notice! Only one channel can have 'Motor RPM' option active. |
| Decimals | Advanced | Integer | 3 | Number of decimals in the logged data |
| Sampling time | Advanced | Option | 10ms | Sampling time for the channel |
| Filter | Advanced | Integer | 1 | Gives the possibility to filter accelerometer values. 1 = no filter, 9 = max filter |
| Unit | Advanced | Option | G Force (G) | Select the unit for exported data file. No effect on the calculation. |
| Size in bytes | Advanced | Option | 16bit | Defines data sample size in raw data. Options are 16bit value and 32bit value |
Example configuration
Here is an example how to set the RPM measurement channel for1/8th scale nitro buggy (AE RC8B3.2) and same principles work for all nitro carss. Below are some assumptions for the configuration.
- Clutch bell: 14T
- Spur gear: 46T
- Tire diameter: 10.5cm
- Internal driver ratio: 3.38 with 44T ring gear and 13T pinion gear
- Magnets are installed on crankshaft
To configure the input in Connector, please follow the steps below
- Open TestLogger Connector and either modify existing config or create new
- Do all changes in Basic mode
- Set pinion gear and spur gear on general tab
- Change to Speed configuration and modify input 1
- Set radius to 0.0525. This the radius in meters which comes from the diameter (10.5cm / (2 * 100)) = 0.0525m
- Set internal ratio to 3.38 based on manufacturer information or calculate it yourself from the gears
- Set magnets to 2 if you use two magnets.
- Save config to device
- Activate calibration mode and do a test run on bench to check if values are ok.