Specifications / Modbus Protocol / API / Bricklets / Linear Poti Bricklet

Modbus - Linear Poti Bricklet¶

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

API¶

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

Basic Functions¶

BrickletLinearPoti.get_position¶

Function ID:	1
Request:	empty payload
Response:	position – Type: uint16, Range: [0 to 100]

Returns the position of the linear potentiometer. The value is between 0 (slider down) and 100 (slider up).

If you want to get the position periodically, it is recommended to use the CALLBACK_POSITION callback and set the period with set_position_callback_period.

Advanced Functions¶

BrickletLinearPoti.get_analog_value¶

Function ID:	2
Request:	empty payload
Response:	value – Type: uint16, Range: [0 to 2¹² - 1]

Returns the value as read by a 12-bit analog-to-digital converter.

Note

The value returned by get_position is averaged over several samples to yield less noise, while get_analog_value gives back raw unfiltered analog values. The only reason to use get_analog_value is, if you need the full resolution of the analog-to-digital converter.

If you want the analog value periodically, it is recommended to use the CALLBACK_ANALOG_VALUE callback and set the period with set_analog_value_callback_period.

BrickletLinearPoti.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¶

BrickletLinearPoti.set_position_callback_period¶

Function ID:	3
Request:	period – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Response:	no response

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

The CALLBACK_POSITION callback is only triggered if the position has changed since the last triggering.

BrickletLinearPoti.get_position_callback_period¶

Function ID:	4
Request:	empty payload
Response:	period – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by set_position_callback_period.

BrickletLinearPoti.set_analog_value_callback_period¶

Function ID:	5
Request:	period – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Response:	no response

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

The CALLBACK_ANALOG_VALUE callback is only triggered if the analog value has changed since the last triggering.

BrickletLinearPoti.get_analog_value_callback_period¶

Function ID:	6
Request:	empty payload
Response:	period – Type: uint32, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by set_analog_value_callback_period.

BrickletLinearPoti.set_position_callback_threshold¶

Function ID:	7
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_POSITION_REACHED callback.

The following options are possible:

Option	Description
'x'	Callback is turned off
'o'	Callback is triggered when the position is outside the min and max values
'i'	Callback is triggered when the position is inside the min and max values
'<'	Callback is triggered when the position is smaller than the min value (max is ignored)
'>'	Callback is triggered when the position 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

BrickletLinearPoti.get_position_callback_threshold¶

Function ID:	8
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_position_callback_threshold.

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

For option:

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

BrickletLinearPoti.set_analog_value_callback_threshold¶

Function ID:	9
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_ANALOG_VALUE_REACHED callback.

The following options are possible:

Option	Description
'x'	Callback is turned off
'o'	Callback is triggered when the analog value is outside the min and max values
'i'	Callback is triggered when the analog value is inside the min and max values
'<'	Callback is triggered when the analog value is smaller than the min value (max is ignored)
'>'	Callback is triggered when the analog 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

BrickletLinearPoti.get_analog_value_callback_threshold¶

Function ID:	10
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_analog_value_callback_threshold.

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

For option:

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

BrickletLinearPoti.set_debounce_period¶

Function ID:	11
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_POSITION_REACHED,
CALLBACK_ANALOG_VALUE_REACHED

are triggered, if the thresholds

set_position_callback_threshold,
set_analog_value_callback_threshold

keep being reached.

BrickletLinearPoti.get_debounce_period¶

Function ID:	12
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¶

BrickletLinearPoti.CALLBACK_POSITION¶

Function ID:	13
Response:	position – Type: uint16, Range: [0 to 100]

This callback is triggered periodically with the period that is set by set_position_callback_period. The response value is the position of the linear potentiometer.

The CALLBACK_POSITION callback is only triggered if the position has changed since the last triggering.

BrickletLinearPoti.CALLBACK_ANALOG_VALUE¶

Function ID:	14
Response:	value – Type: uint16, Range: [0 to 2¹² - 1]

This callback is triggered periodically with the period that is set by set_analog_value_callback_period. The response value is the analog value of the Linear Potentiometer.

The CALLBACK_ANALOG_VALUE callback is only triggered if the position has changed since the last triggering.

BrickletLinearPoti.CALLBACK_POSITION_REACHED¶

Function ID:	15
Response:	position – Type: uint16, Range: [0 to 100]

This callback is triggered when the threshold as set by set_position_callback_threshold is reached. The response value is the position of the linear potentiometer.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by set_debounce_period.

BrickletLinearPoti.CALLBACK_ANALOG_VALUE_REACHED¶

Function ID:	16
Response:	value – Type: uint16, Range: [0 to 2¹² - 1]

This callback is triggered when the threshold as set by set_analog_value_callback_threshold is reached. The response value is the analog value of the linear potentiometer.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by set_debounce_period.