Specifications / Modbus Protocol / API / Bricklets / Line Bricklet

Modbus - Line Bricklet¶

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.

API¶

A general description of the Modbus protocol structure can be found here.

Basic Functions¶

BrickletLine.get_reflectivity¶

Function ID:	1
Request:	empty payload
Response:	reflectivity – Type: uint16, Range: [0 to 2¹² - 1]

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_REFLECTIVITY callback and set the period with set_reflectivity_callback_period.

Advanced Functions¶

BrickletLine.get_identity¶

Function ID:	255
Request:	empty payload
Response:	uid – Type: char[8] connected_uid – Type: char[8] position – Type: char, Range: ['a' to 'h', 'z'] hardware_version – Type: uint8[3] 0: major – Type: uint8, Range: [0 to 255] 1: minor – Type: uint8, Range: [0 to 255] 2: revision – Type: uint8, Range: [0 to 255] firmware_version – Type: uint8[3] 0: major – Type: uint8, Range: [0 to 255] 1: minor – Type: uint8, Range: [0 to 255] 2: revision – Type: uint8, Range: [0 to 255] device_identifier – Type: uint16, Range: [0 to 2¹⁶ - 1]

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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

The device identifier numbers can be found here.

Callback Configuration Functions¶

BrickletLine.set_reflectivity_callback_period¶

Function ID:	2
Request:	period – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Response:	no response

Sets the period with which the CALLBACK_REFLECTIVITY callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_REFLECTIVITY callback is only triggered if the reflectivity has changed since the last triggering.

BrickletLine.get_reflectivity_callback_period¶

Function ID:	3
Request:	empty payload
Response:	period – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by set_reflectivity_callback_period.

BrickletLine.set_reflectivity_callback_threshold¶

Function ID:	4
Request:	option – Type: char, Range: See meanings, Default: 'x' min – Type: uint16, Range: [0 to 2¹⁶ - 1], Default: 0 max – Type: uint16, Range: [0 to 2¹⁶ - 1], Default: 0
Response:	no response

Sets the thresholds for the CALLBACK_REFLECTIVITY_REACHED callback.

The following options are possible:

Option	Description
'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 following meanings are defined for the elements of this function:

For option:

'x' = Off
'o' = Outside
'i' = Inside
'<' = Smaller
'>' = Greater

BrickletLine.get_reflectivity_callback_threshold¶

Function ID:	5
Request:	empty payload
Response:	option – Type: char, Range: See meanings, Default: 'x' min – Type: uint16, Range: [0 to 2¹⁶ - 1], Default: 0 max – Type: uint16, Range: [0 to 2¹⁶ - 1], Default: 0

Returns the threshold as set by set_reflectivity_callback_threshold.

The following meanings are defined for the elements of this function:

For option:

'x' = Off
'o' = Outside
'i' = Inside
'<' = Smaller
'>' = Greater

BrickletLine.set_debounce_period¶

Function ID:	6
Request:	debounce – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100
Response:	no response

Sets the period with which the threshold callback

CALLBACK_REFLECTIVITY_REACHED

is triggered, if the threshold

set_reflectivity_callback_threshold

keeps being reached.

BrickletLine.get_debounce_period¶

Function ID:	7
Request:	empty payload
Response:	debounce – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100

Returns the debounce period as set by set_debounce_period.

Callbacks¶

BrickletLine.CALLBACK_REFLECTIVITY¶

Function ID:	8
Response:	reflectivity – Type: uint16, Range: [0 to 2¹² - 1]

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.

The CALLBACK_REFLECTIVITY callback is only triggered if the reflectivity has changed since the last triggering.

BrickletLine.CALLBACK_REFLECTIVITY_REACHED¶

Function ID:	9
Response:	reflectivity – Type: uint16, Range: [0 to 2¹² - 1]

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.