Specifications / Modbus Protocol / API / Bricklets (Discontinued) / Distance US Bricklet

Modbus - Distance US Bricklet¶

This is the description of the Modbus protocol for the Distance US Bricklet. General information and technical specifications for the Distance US Bricklet are summarized in its hardware description.

API¶

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

Basic Functions¶

BrickletDistanceUS.get_distance_value¶

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

Returns the current distance value measured by the sensor. A small value corresponds to a small distance, a big value corresponds to a big distance. The relation between the measured distance value and the actual distance is affected by the 5V supply voltage (deviations in the supply voltage result in deviations in the distance values) and is non-linear (resolution is bigger at close range).

If you want to get the distance value periodically, it is recommended to use the CALLBACK_DISTANCE callback and set the period with set_distance_callback_period.

Advanced Functions¶

BrickletDistanceUS.set_moving_average¶

Function ID:	10
Request:	average – Type: uint8, Range: [0 to 100], Default: 20
Response:	no response

Sets the length of a moving averaging for the distance value.

Setting the length to 0 will turn the averaging completely off. With less averaging, there is more noise on the data.

BrickletDistanceUS.get_moving_average¶

Function ID:	11
Request:	empty payload
Response:	average – Type: uint8, Range: [0 to 100], Default: 20

Returns the length moving average as set by set_moving_average.

BrickletDistanceUS.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¶

BrickletDistanceUS.set_distance_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_DISTANCE callback is triggered periodically. A value of 0 turns the callback off.

Der CALLBACK_DISTANCE callback is only triggered if the distance value has changed since the last triggering.

BrickletDistanceUS.get_distance_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_distance_callback_period.

BrickletDistanceUS.set_distance_callback_threshold¶

Function ID:	4
Request:	option – Type: char, Range: See meanings, Default: 'x' min – Type: uint16, Range: [0 to 2¹² - 1] max – Type: uint16, Range: [0 to 2¹² - 1]
Response:	no response

Sets the thresholds for the CALLBACK_DISTANCE_REACHED callback.

The following options are possible:

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

For option:

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

BrickletDistanceUS.get_distance_callback_threshold¶

Function ID:	5
Request:	empty payload
Response:	option – Type: char, Range: See meanings, Default: 'x' min – Type: uint16, Range: [0 to 2¹² - 1] max – Type: uint16, Range: [0 to 2¹² - 1]

Returns the threshold as set by set_distance_callback_threshold.

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

For option:

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

BrickletDistanceUS.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 callbacks

CALLBACK_DISTANCE_REACHED,

are triggered, if the thresholds

set_distance_callback_threshold,

keep being reached.

BrickletDistanceUS.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¶

BrickletDistanceUS.CALLBACK_DISTANCE¶

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

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.

The CALLBACK_DISTANCE callback is only triggered if the distance value has changed since the last triggering.

BrickletDistanceUS.CALLBACK_DISTANCE_REACHED¶

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

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.