Modbus - Rotary Encoder Bricklet – Tinkerforge

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# 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.

  `CALLBACK_COUNT` 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).

`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`.

`BrickletRotaryEncoder.``set_debounce_period`

  Function ID: | 6

  Request:

  - debounce -- uint32

  Response: | no response

  Sets the period in ms with which the threshold callback

  - `CALLBACK_COUNT_REACHED`

  is triggered, if the thresholds

  - `set_count_callback_threshold`

  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.

  `CALLBACK_COUNT` 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.

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