Modbus - Rotary Encoder Bricklet

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

API

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

Basic Functions

BrickletRotaryEncoder.get_count
Function ID:

1

Request:
  • reset -- bool
Response:
  • count -- int32

Returns the current count of the encoder. If you set reset to true, the count is set back to 0 directly after the current count is read.

The encoder has 24 steps per rotation

Turning the encoder to the left decrements the counter, so a negative count is possible.

BrickletRotaryEncoder.is_pressed
Function ID:

10

Request:

empty payload

Response:
  • pressed -- bool

Returns true if the button is pressed and false otherwise.

It is recommended to use the CALLBACK_PRESSED and CALLBACK_RELEASED callbacks to handle the button.

Advanced Functions

BrickletRotaryEncoder.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

BrickletRotaryEncoder.set_count_callback_period
Function ID:

2

Request:
  • period -- uint32
Response:

no response

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

The CALLBACK_COUNT callback is only triggered if the count has changed since the last triggering.

The default value is 0.

BrickletRotaryEncoder.get_count_callback_period
Function ID:

3

Request:

empty payload

Response:
  • period -- uint32

Returns the period as set by set_count_callback_period.

BrickletRotaryEncoder.set_count_callback_threshold
Function ID:

4

Request:
  • option -- char
  • min -- int32
  • max -- int32
Response:

no response

Sets the thresholds for the CALLBACK_COUNT_REACHED callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the count is outside the min and max values
'i' Callback is triggered when the count is inside the min and max values
'<' Callback is triggered when the count is smaller than the min value (max is ignored)
'>' Callback is triggered when the count 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
BrickletRotaryEncoder.get_count_callback_threshold
Function ID:

5

Request:

empty payload

Response:
  • option -- char
  • min -- int32
  • max -- int32

Returns the threshold as set by set_count_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
BrickletRotaryEncoder.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 thresholds

keeps being reached.

The default value is 100.

BrickletRotaryEncoder.get_debounce_period
Function ID:

7

Request:

empty payload

Response:
  • debounce -- uint32

Returns the debounce period as set by set_debounce_period.

Callbacks

BrickletRotaryEncoder.CALLBACK_COUNT
Function ID:

8

Response:
  • count -- int32

This callback is triggered periodically with the period that is set by set_count_callback_period. The response value is the count of the encoder.

The CALLBACK_COUNT callback is only triggered if the count has changed since the last triggering.

BrickletRotaryEncoder.CALLBACK_COUNT_REACHED
Function ID:

9

Response:
  • count -- int32

This callback is triggered when the threshold as set by set_count_callback_threshold is reached. The response value is the count of the encoder.

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

BrickletRotaryEncoder.CALLBACK_PRESSED
Function ID:11
Response:empty payload

This callback is triggered when the button is pressed.

BrickletRotaryEncoder.CALLBACK_RELEASED
Function ID:12
Response:empty payload

This callback is triggered when the button is released.