This is the description of the Modbus protocol for the Line Bricklet. General information and technical specifications for the Line 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 currently measured reflectivity. The reflectivity is a value between 0 (not reflective) and 4095 (very reflective).
Usually black has a low reflectivity while white has a high reflectivity.
If you want to get the reflectivity periodically, it is recommended to use the callback CALLBACK_REFLECTIVITY and set the period with set_reflectivity_callback_period.
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: | 2 |
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Request: |
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Response: | no response |
Sets the period in ms with which the CALLBACK_REFLECTIVITY callback is triggered periodically. A value of 0 turns the callback off.
CALLBACK_REFLECTIVITY is only triggered if the reflectivity has changed since the last triggering.
The default value is 0.
Function ID: | 3 |
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Request: | empty payload |
Response: |
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Returns the period as set by set_reflectivity_callback_period.
Function ID: | 4 |
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Request: |
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Response: | no response |
Sets the thresholds for the CALLBACK_REFLECTIVITY_REACHED callback.
The following options are possible:
Option | Description |
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'x' | Callback is turned off |
'o' | Callback is triggered when the reflectivity is outside the min and max values |
'i' | Callback is triggered when the reflectivity is inside the min and max values |
'<' | Callback is triggered when the reflectivity is smaller than the min value (max is ignored) |
'>' | Callback is triggered when the reflectivity is greater than the min value (max is ignored) |
The default value is ('x', 0, 0).
Function ID: | 5 |
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Request: | empty payload |
Response: |
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Returns the threshold as set by set_reflectivity_callback_threshold.
Function ID: | 6 |
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Request: |
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Response: | no response |
Sets the period in ms with which the threshold callback
is triggered, if the threshold
keeps being reached.
The default value is 100.
Function ID: | 7 |
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Request: | empty payload |
Response: |
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Returns the debounce period as set by set_debounce_period.
Function ID: | 8 |
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Response: |
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This callback is triggered periodically with the period that is set by set_reflectivity_callback_period. The response value is the reflectivity of the sensor.
CALLBACK_REFLECTIVITY is only triggered if the reflectivity has changed since the last triggering.
Function ID: | 9 |
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Response: |
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This callback is triggered when the threshold as set by set_reflectivity_callback_threshold is reached. The response value is the reflectivity of the sensor.
If the threshold keeps being reached, the callback is triggered periodically with the period as set by set_debounce_period.