Note
This Bricklet is currently in the prototype stage and the software/hardware as well as the documentation is in an incomplete state.
This is the description of the Modbus protocol for the Laser Range Finder Bricklet. General information and technical specifications for the Laser Range Finder Bricklet are summarized in its hardware description.
A general description of the Modbus protocol structure can be found here.
Function ID: | 1 |
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Request: | empty payload |
Response: |
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Returns the measured distance. The value has a range of 0 to 4000 and is given in cm.
The Laser Range Finder Bricklet knows different modes. Distances are only measured in the distance measurement mode, see set_mode. Also the laser has to be enabled, see enable_laser.
If you want to get the distance periodically, it is recommended to use the callback CALLBACK_DISTANCE and set the period with set_distance_callback_period.
Function ID: | 2 |
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Request: | empty payload |
Response: |
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Returns the measured velocity. The value has a range of 0 to 12700 and is given in 1/100 m/s.
The Laser Range Finder Bricklet knows different modes. Velocity is only measured in the velocity measurement modes, see set_mode. Also the laser has to be enabled, see enable_laser.
If you want to get the velocity periodically, it is recommended to use the callback CALLBACK_VELOCITY and set the period with set_velocity_callback_period.
Function ID: | 15 |
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Request: |
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Response: | no response |
The LIDAR has five different modes. One mode is for distance measurements and four modes are for velocity measurements with different ranges.
The following modes are available:
The default mode is 0 (distance is measured).
Function ID: | 16 |
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Request: | empty payload |
Response: |
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Returns the mode as set by set_mode.
Function ID: | 17 |
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Request: | empty payload |
Response: | no response |
Activates the laser of the LIDAR.
We recommend that you wait 250ms after enabling the laser before the first call of get_distance to ensure stable measurements.
Function ID: | 18 |
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Request: | empty payload |
Response: | no response |
Deactivates the laser of the LIDAR.
Function ID: | 19 |
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Request: | empty payload |
Response: |
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Returns true if the laser is enabled, false otherwise.
Function ID: | 13 |
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Request: |
|
Response: | no response |
Sets the length of a moving averaging for the distance and velocity.
Setting the length to 0 will turn the averaging completely off. With less averaging, there is more noise on the data.
The range for the averaging is 0-30.
The default value is 10.
Function ID: | 14 |
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Request: | empty payload |
Response: |
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Returns the length moving average as set by set_moving_average.
Function ID: | 255 |
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Request: | empty payload |
Response: |
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Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.
The position can be 'a', 'b', 'c' or 'd'.
The device identifier numbers can be found here.
Function ID: | 3 |
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Request: |
|
Response: | no response |
Sets the period in ms with which the CALLBACK_DISTANCE callback is triggered periodically. A value of 0 turns the callback off.
CALLBACK_DISTANCE is only triggered if the distance value has changed since the last triggering.
The default value is 0.
Function ID: | 4 |
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Request: | empty payload |
Response: |
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Returns the period as set by set_distance_callback_period.
Function ID: | 5 |
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Request: |
|
Response: | no response |
Sets the period in ms with which the CALLBACK_VELOCITY callback is triggered periodically. A value of 0 turns the callback off.
CALLBACK_VELOCITY is only triggered if the velocity value has changed since the last triggering.
The default value is 0.
Function ID: | 6 |
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Request: | empty payload |
Response: |
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Returns the period as set by set_velocity_callback_period.
Function ID: | 7 |
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Request: |
|
Response: | no response |
Sets the thresholds for the CALLBACK_DISTANCE_REACHED callback.
The following options are possible:
Option | Description |
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'x' | Callback is turned off |
'o' | Callback is triggered when the distance value is outside the min and max values |
'i' | Callback is triggered when the distance value is inside the min and max values |
'<' | Callback is triggered when the distance value is smaller than the min value (max is ignored) |
'>' | Callback is triggered when the distance value is greater than the min value (max is ignored) |
The default value is ('x', 0, 0).
Function ID: | 8 |
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Request: | empty payload |
Response: |
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Returns the threshold as set by set_distance_callback_threshold.
Function ID: | 9 |
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Request: |
|
Response: | no response |
Sets the thresholds for the CALLBACK_VELOCITY_REACHED callback.
The following options are possible:
Option | Description |
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'x' | Callback is turned off |
'o' | Callback is triggered when the velocity is outside the min and max values |
'i' | Callback is triggered when the velocity is inside the min and max values |
'<' | Callback is triggered when the velocity is smaller than the min value (max is ignored) |
'>' | Callback is triggered when the velocity is greater than the min value (max is ignored) |
The default value is ('x', 0, 0).
Function ID: | 10 |
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Request: | empty payload |
Response: |
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Returns the threshold as set by set_velocity_callback_threshold.
Function ID: | 11 |
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Request: |
|
Response: | no response |
Sets the period in ms with which the threshold callbacks
are triggered, if the thresholds
keep being reached.
The default value is 100.
Function ID: | 12 |
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Request: | empty payload |
Response: |
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Returns the debounce period as set by set_debounce_period.
Function ID: | 20 |
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Response: |
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This callback is triggered periodically with the period that is set by set_distance_callback_period. The response value is the distance value of the sensor.
CALLBACK_DISTANCE is only triggered if the distance value has changed since the last triggering.
Function ID: | 21 |
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Response: |
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This callback is triggered periodically with the period that is set by set_velocity_callback_period. The response value is the velocity value of the sensor.
CALLBACK_VELOCITY is only triggered if the velocity has changed since the last triggering.
Function ID: | 22 |
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Response: |
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This callback is triggered when the threshold as set by set_distance_callback_threshold is reached. The response value is the distance value of the sensor.
If the threshold keeps being reached, the callback is triggered periodically with the period as set by set_debounce_period.
Function ID: | 23 |
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Response: |
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This callback is triggered when the threshold as set by set_velocity_callback_threshold is reached. The response value is the velocity value of the sensor.
If the threshold keeps being reached, the callback is triggered periodically with the period as set by set_debounce_period.