LabVIEW - Rotary Encoder Bricklet

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

An installation guide for the LabVIEW API bindings is part of their general description.

API

Generally, every method of the LabVIEW bindings that outputs a value can report a Tinkerforge.TimeoutException. This error gets reported if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody plugs the device out). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

The namespace for all Brick/Bricklet bindings and the IPConnection is Tinkerforge.*.

Basic Functions

BrickletRotaryEncoder(uid, ipcon) → rotaryEncoder
Input:
  • uid – Type: String
  • ipcon – Type: .NET Refnum (IPConnection)
Output:
  • rotaryEncoder – Type: .NET Refnum (BrickletRotaryEncoder)

Creates an object with the unique device ID uid. This object can then be used after the IP Connection is connected (see examples above).

BrickletRotaryEncoder.GetCount(reset) → count
Input:
  • reset – Type: Boolean
Output:
  • count – Type: Int32, Range: [-231 to 231 - 1]

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.IsPressed() → pressed
Output:
  • pressed – Type: Boolean

Returns true if the button is pressed and false otherwise.

It is recommended to use the PressedCallback and ReleasedCallback callbacks to handle the button.

Advanced Functions

BrickletRotaryEncoder.GetAPIVersion() → apiVersion
Output:
  • apiVersion – Type: Byte[3], Range: [0 to 255]

Returns the version of the API definition (major, minor, revision) implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

BrickletRotaryEncoder.GetResponseExpected(functionId) → responseExpected
Input:
  • functionId – Type: Byte, Range: See constants
Output:
  • responseExpected – Type: Boolean

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by SetResponseExpected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BrickletRotaryEncoder.FUNCTION_SET_COUNT_CALLBACK_PERIOD = 2
  • BrickletRotaryEncoder.FUNCTION_SET_COUNT_CALLBACK_THRESHOLD = 4
  • BrickletRotaryEncoder.FUNCTION_SET_DEBOUNCE_PERIOD = 6
BrickletRotaryEncoder.SetResponseExpected(functionId, responseExpected)
Input:
  • functionId – Type: Byte, Range: See constants
  • responseExpected – Type: Boolean

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BrickletRotaryEncoder.FUNCTION_SET_COUNT_CALLBACK_PERIOD = 2
  • BrickletRotaryEncoder.FUNCTION_SET_COUNT_CALLBACK_THRESHOLD = 4
  • BrickletRotaryEncoder.FUNCTION_SET_DEBOUNCE_PERIOD = 6
BrickletRotaryEncoder.SetResponseExpectedAll(responseExpected)
Input:
  • responseExpected – Type: Boolean

Changes the response expected flag for all setter and callback configuration functions of this device at once.

BrickletRotaryEncoder.GetIdentity() → uid, connectedUid, position, hardwareVersion, firmwareVersion, deviceIdentifier
Output:
  • uid – Type: String, Length: up to 8
  • connectedUid – Type: String, Length: up to 8
  • position – Type: Char
  • hardwareVersion – Type: Byte[3], Range: [0 to 255]
  • firmwareVersion – Type: Byte[3], Range: [0 to 255]
  • deviceIdentifier – Type: Int32, 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' or 'd'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

BrickletRotaryEncoder.SetCountCallbackPeriod(period)
Input:
  • period – Type: Int64, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

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

BrickletRotaryEncoder.GetCountCallbackPeriod() → period
Output:
  • period – Type: Int64, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by SetCountCallbackPeriod().

BrickletRotaryEncoder.SetCountCallbackThreshold(option, min, max)
Input:
  • option – Type: Char, Range: See constants, Default: "x"
  • min – Type: Int32, Range: [-231 to 231 - 1]
  • max – Type: Int32, Range: [-231 to 231 - 1]

Sets the thresholds for the CountReachedCallback 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 constants are available for this function:

For option:

  • BrickletRotaryEncoder.THRESHOLD_OPTION_OFF = "x"
  • BrickletRotaryEncoder.THRESHOLD_OPTION_OUTSIDE = "o"
  • BrickletRotaryEncoder.THRESHOLD_OPTION_INSIDE = "i"
  • BrickletRotaryEncoder.THRESHOLD_OPTION_SMALLER = "<"
  • BrickletRotaryEncoder.THRESHOLD_OPTION_GREATER = ">"
BrickletRotaryEncoder.GetCountCallbackThreshold() → option, min, max
Output:
  • option – Type: Char, Range: See constants, Default: "x"
  • min – Type: Int32, Range: [-231 to 231 - 1]
  • max – Type: Int32, Range: [-231 to 231 - 1]

Returns the threshold as set by SetCountCallbackThreshold().

The following constants are available for this function:

For option:

  • BrickletRotaryEncoder.THRESHOLD_OPTION_OFF = "x"
  • BrickletRotaryEncoder.THRESHOLD_OPTION_OUTSIDE = "o"
  • BrickletRotaryEncoder.THRESHOLD_OPTION_INSIDE = "i"
  • BrickletRotaryEncoder.THRESHOLD_OPTION_SMALLER = "<"
  • BrickletRotaryEncoder.THRESHOLD_OPTION_GREATER = ">"
BrickletRotaryEncoder.SetDebouncePeriod(debounce)
Input:
  • debounce – Type: Int64, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Sets the period with which the threshold callback

is triggered, if the thresholds

keeps being reached.

BrickletRotaryEncoder.GetDebouncePeriod() → debounce
Output:
  • debounce – Type: Int64, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by SetDebouncePeriod().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by assigning a function to a callback property of the device object. The available callback property and their type of parameters are described below.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

event BrickletRotaryEncoder.CountCallback → sender, count
Callback Output:
  • sender – Type: .NET Refnum (BrickletRotaryEncoder)
  • count – Type: Int32, Range: [-231 to 231 - 1]

This callback is triggered periodically with the period that is set by SetCountCallbackPeriod(). The parameter is the count of the encoder.

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

event BrickletRotaryEncoder.CountReachedCallback → sender, count
Callback Output:
  • sender – Type: .NET Refnum (BrickletRotaryEncoder)
  • count – Type: Int32, Range: [-231 to 231 - 1]

This callback is triggered when the threshold as set by SetCountCallbackThreshold() is reached. The parameter is the count of the encoder.

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

event BrickletRotaryEncoder.PressedCallback → sender
Callback Output:
  • sender – Type: .NET Refnum (BrickletRotaryEncoder)

This callback is triggered when the button is pressed.

event BrickletRotaryEncoder.ReleasedCallback → sender
Callback Output:
  • sender – Type: .NET Refnum (BrickletRotaryEncoder)

This callback is triggered when the button is released.

Constants

BrickletRotaryEncoder.DEVICE_IDENTIFIER

This constant is used to identify a Rotary Encoder Bricklet.

The GetIdentity() function and the IPConnection.EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

BrickletRotaryEncoder.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Rotary Encoder Bricklet.