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 -- uint16

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 -- char[8]
  • connected_uid -- char[8]
  • position -- char
  • hardware_version -- uint8[3]
  • firmware_version -- uint8[3]
  • device_identifier -- uint16

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

Callback Configuration Functions

BrickletLine.set_reflectivity_callback_period
Function ID:

2

Request:
  • period -- uint32
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.

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

The default value is 0.

BrickletLine.get_reflectivity_callback_period
Function ID:

3

Request:

empty payload

Response:
  • period -- uint32

Returns the period as set by set_reflectivity_callback_period.

BrickletLine.set_reflectivity_callback_threshold
Function ID:

4

Request:
  • option -- char
  • min -- uint16
  • max -- uint16
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 default value is ('x', 0, 0).

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

  • x: off, for option
  • o: outside, for option
  • i: inside, for option
  • <: smaller, for option
  • >: greater, for option
BrickletLine.get_reflectivity_callback_threshold
Function ID:

5

Request:

empty payload

Response:
  • option -- char
  • min -- uint16
  • max -- uint16

Returns the threshold as set by set_reflectivity_callback_threshold.

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

  • x: off, for option
  • o: outside, for option
  • i: inside, for option
  • <: smaller, for option
  • >: greater, for option
BrickletLine.set_debounce_period
Function ID:

6

Request:
  • debounce -- uint32
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.

BrickletLine.get_debounce_period
Function ID:

7

Request:

empty payload

Response:
  • debounce -- uint32

Returns the debounce period as set by set_debounce_period.

Callbacks

BrickletLine.CALLBACK_REFLECTIVITY
Function ID:

8

Response:
  • reflectivity -- uint16

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 -- uint16

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.