Encoder

java.lang.Object
- edu.wpi.first.wpilibj.SensorBase
- - edu.wpi.first.wpilibj.Encoder

All Implemented Interfaces:

CounterBase, LiveWindowSendable, PIDSource, Sendable
```
public class Encoder
extends SensorBase
implements CounterBase, PIDSource, LiveWindowSendable
```
Class to read quadrature encoders. Quadrature encoders are devices that count shaft rotation and can sense direction. The output of the Encoder class is an integer that can count either up or down, and can go negative for reverse direction counting. When creating Encoders, a direction can be supplied that inverts the sense of the output to make code more readable if the encoder is mounted such that forward movement generates negative values. Quadrature encoders have two digital outputs, an A Channel and a B Channel, that are out of phase with each other for direction sensing.
All encoders will immediately start counting - reset() them if you need them to be zeroed before use.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class Encoder.IndexingType
- Nested classes/interfaces inherited from interface edu.wpi.first.wpilibj.CounterBase
  CounterBase.EncodingType

Nested Classes
Modifier and Type	Class and Description
`static class`	`Encoder.IndexingType`

Field Summary

Fields
Modifier and Type	Field and Description
`protected DigitalSource`	`m_aSource` The a source.
`protected DigitalSource`	`m_bSource` The b source.
`protected DigitalSource`	`m_indexSource` The index source.

Fields inherited from class edu.wpi.first.wpilibj.SensorBase
kAnalogInputChannels, kAnalogOutputChannels, kDigitalChannels, kPCMModules, kPDPChannels, kPDPModules, kPwmChannels, kRelayChannels, kSolenoidChannels, kSystemClockTicksPerMicrosecond

Constructor Summary

Constructors
Constructor and Description
`Encoder(DigitalSource sourceA, DigitalSource sourceB)` Encoder constructor.
`Encoder(DigitalSource sourceA, DigitalSource sourceB, boolean reverseDirection)` Encoder constructor.
`Encoder(DigitalSource sourceA, DigitalSource sourceB, boolean reverseDirection, CounterBase.EncodingType encodingType)` Encoder constructor.
`Encoder(DigitalSource sourceA, DigitalSource sourceB, DigitalSource indexSource)` Encoder constructor.
`Encoder(DigitalSource sourceA, DigitalSource sourceB, DigitalSource indexSource, boolean reverseDirection)` Encoder constructor.
`Encoder(int channelA, int channelB)` Encoder constructor.
`Encoder(int channelA, int channelB, boolean reverseDirection)` Encoder constructor.
`Encoder(int channelA, int channelB, boolean reverseDirection, CounterBase.EncodingType encodingType)` Encoder constructor.
`Encoder(int channelA, int channelB, int indexChannel)` Encoder constructor.
`Encoder(int channelA, int channelB, int indexChannel, boolean reverseDirection)` Encoder constructor.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`void`	`free()` Free the resources used by this object.
`int`	`get()` Gets the current count.
`boolean`	`getDirection()` The last direction the encoder value changed.
`double`	`getDistance()` Get the distance the robot has driven since the last reset as scaled by the value from `setDistancePerPulse(double)`.
`int`	`getEncodingScale()` Used to divide raw edge counts down to spec'd counts.
`int`	`getFPGAIndex()`
`double`	`getPeriod()` Deprecated. Use getRate() in favor of this method.
`PIDSourceType`	`getPIDSourceType()` Get which parameter of the device you are using as a process control variable.
`double`	`getRate()` Get the current rate of the encoder.
`int`	`getRaw()` Gets the raw value from the encoder.
`int`	`getSamplesToAverage()` Get the Samples to Average which specifies the number of samples of the timer to average when calculating the period.
`java.lang.String`	`getSmartDashboardType()` Live Window code, only does anything if live window is activated.
`boolean`	`getStopped()` Determine if the encoder is stopped.
`ITable`	`getTable()` The table that is associated with this `Sendable`.
`void`	`initTable(ITable subtable)` Initializes a table for this `Sendable` object.
`double`	`pidGet()` Implement the PIDSource interface.
`void`	`reset()` Reset the Encoder distance to zero.
`void`	`setDistancePerPulse(double distancePerPulse)` Set the distance per pulse for this encoder.
`void`	`setIndexSource(DigitalSource source)` Set the index source for the encoder.
`void`	`setIndexSource(DigitalSource source, Encoder.IndexingType type)` Set the index source for the encoder.
`void`	`setIndexSource(int channel)` Set the index source for the encoder.
`void`	`setIndexSource(int channel, Encoder.IndexingType type)` Set the index source for the encoder.
`void`	`setMaxPeriod(double maxPeriod)` Sets the maximum period for stopped detection.
`void`	`setMinRate(double minRate)` Set the minimum rate of the device before the hardware reports it stopped.
`void`	`setPIDSourceType(PIDSourceType pidSource)` Set which parameter of the encoder you are using as a process control variable.
`void`	`setReverseDirection(boolean reverseDirection)` Set the direction sensing for this encoder.
`void`	`setSamplesToAverage(int samplesToAverage)` Set the Samples to Average which specifies the number of samples of the timer to average when calculating the period.
`void`	`startLiveWindowMode()` Start having this sendable object automatically respond to value changes reflect the value on the table.
`void`	`stopLiveWindowMode()` Stop having this sendable object automatically respond to value changes.
`void`	`updateTable()` Update the table for this sendable object with the latest values.

Methods inherited from class edu.wpi.first.wpilibj.SensorBase
checkAnalogInputChannel, checkAnalogOutputChannel, checkDigitalChannel, checkPDPChannel, checkPDPModule, checkPWMChannel, checkRelayChannel, checkSolenoidChannel, checkSolenoidModule, getDefaultSolenoidModule, setDefaultSolenoidModule

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - m_aSource
```
protected DigitalSource m_aSource
```
    The a source.
  - m_bSource
```
protected DigitalSource m_bSource
```
    The b source.
  - m_indexSource
```
protected DigitalSource m_indexSource
```
    The index source.
- Constructor Detail
  - Encoder
```
public Encoder(int channelA,
               int channelB,
               boolean reverseDirection)
```
    Encoder constructor. Construct a Encoder given a and b channels.
    The encoder will start counting immediately.
    
    Parameters:
    
    channelA - The a channel DIO channel. 0-9 are on-board, 10-25 are on the MXP port
    
    channelB - The b channel DIO channel. 0-9 are on-board, 10-25 are on the MXP port
    
    reverseDirection - represents the orientation of the encoder and inverts the output values if necessary so forward represents positive values.
  - Encoder
```
public Encoder(int channelA,
               int channelB)
```
    Encoder constructor. Construct a Encoder given a and b channels.
    The encoder will start counting immediately.
    
    Parameters:
    
    channelA - The a channel digital input channel.
    
    channelB - The b channel digital input channel.
  - Encoder
```
public Encoder(int channelA,
               int channelB,
               boolean reverseDirection,
               CounterBase.EncodingType encodingType)
```
    Encoder constructor. Construct a Encoder given a and b channels.
    The encoder will start counting immediately.
    
    Parameters:
    
    channelA - The a channel digital input channel.
    
    channelB - The b channel digital input channel.
    
    reverseDirection - represents the orientation of the encoder and inverts the output values if necessary so forward represents positive values.
    
    encodingType - either k1X, k2X, or k4X to indicate 1X, 2X or 4X decoding. If 4X is selected, then an encoder FPGA object is used and the returned counts will be 4x the encoder spec'd value since all rising and falling edges are counted. If 1X or 2X are selected then a m_counter object will be used and the returned value will either exactly match the spec'd count or be double (2x) the spec'd count.
  - Encoder
```
public Encoder(int channelA,
               int channelB,
               int indexChannel,
               boolean reverseDirection)
```
    Encoder constructor. Construct a Encoder given a and b channels. Using an index pulse forces 4x encoding
    The encoder will start counting immediately.
    
    Parameters:
    
    channelA - The a channel digital input channel.
    
    channelB - The b channel digital input channel.
    
    indexChannel - The index channel digital input channel.
    
    reverseDirection - represents the orientation of the encoder and inverts the output values if necessary so forward represents positive values.
  - Encoder
```
public Encoder(int channelA,
               int channelB,
               int indexChannel)
```
    Encoder constructor. Construct a Encoder given a and b channels. Using an index pulse forces 4x encoding
    The encoder will start counting immediately.
    
    Parameters:
    
    channelA - The a channel digital input channel.
    
    channelB - The b channel digital input channel.
    
    indexChannel - The index channel digital input channel.
  - Encoder
```
public Encoder(DigitalSource sourceA,
               DigitalSource sourceB,
               boolean reverseDirection)
```
    Encoder constructor. Construct a Encoder given a and b channels as digital inputs. This is used in the case where the digital inputs are shared. The Encoder class will not allocate the digital inputs and assume that they already are counted.
    The encoder will start counting immediately.
    
    Parameters:
    
    sourceA - The source that should be used for the a channel.
    
    sourceB - the source that should be used for the b channel.
    
    reverseDirection - represents the orientation of the encoder and inverts the output values if necessary so forward represents positive values.
  - Encoder
```
public Encoder(DigitalSource sourceA,
               DigitalSource sourceB)
```
    Encoder constructor. Construct a Encoder given a and b channels as digital inputs. This is used in the case where the digital inputs are shared. The Encoder class will not allocate the digital inputs and assume that they already are counted.
    The encoder will start counting immediately.
    
    Parameters:
    
    sourceA - The source that should be used for the a channel.
    
    sourceB - the source that should be used for the b channel.
  - Encoder
```
public Encoder(DigitalSource sourceA,
               DigitalSource sourceB,
               boolean reverseDirection,
               CounterBase.EncodingType encodingType)
```
    Encoder constructor. Construct a Encoder given a and b channels as digital inputs. This is used in the case where the digital inputs are shared. The Encoder class will not allocate the digital inputs and assume that they already are counted.
    The encoder will start counting immediately.
    
    Parameters:
    
    sourceA - The source that should be used for the a channel.
    
    sourceB - the source that should be used for the b channel.
    
    reverseDirection - represents the orientation of the encoder and inverts the output values if necessary so forward represents positive values.
    
    encodingType - either k1X, k2X, or k4X to indicate 1X, 2X or 4X decoding. If 4X is selected, then an encoder FPGA object is used and the returned counts will be 4x the encoder spec'd value since all rising and falling edges are counted. If 1X or 2X are selected then a m_counter object will be used and the returned value will either exactly match the spec'd count or be double (2x) the spec'd count.
  - Encoder
```
public Encoder(DigitalSource sourceA,
               DigitalSource sourceB,
               DigitalSource indexSource,
               boolean reverseDirection)
```
    Encoder constructor. Construct a Encoder given a, b and index channels as digital inputs. This is used in the case where the digital inputs are shared. The Encoder class will not allocate the digital inputs and assume that they already are counted.
    The encoder will start counting immediately.
    
    Parameters:
    
    sourceA - The source that should be used for the a channel.
    
    sourceB - the source that should be used for the b channel.
    
    indexSource - the source that should be used for the index channel.
    
    reverseDirection - represents the orientation of the encoder and inverts the output values if necessary so forward represents positive values.
  - Encoder
```
public Encoder(DigitalSource sourceA,
               DigitalSource sourceB,
               DigitalSource indexSource)
```
    Encoder constructor. Construct a Encoder given a, b and index channels as digital inputs. This is used in the case where the digital inputs are shared. The Encoder class will not allocate the digital inputs and assume that they already are counted.
    The encoder will start counting immediately.
    
    Parameters:
    
    sourceA - The source that should be used for the a channel.
    
    sourceB - the source that should be used for the b channel.
    
    indexSource - the source that should be used for the index channel.
- Method Detail
  - getFPGAIndex
```
public int getFPGAIndex()
```
    Returns:
    
    The Encoder's FPGA index.
  - getEncodingScale
```
public int getEncodingScale()
```
    Used to divide raw edge counts down to spec'd counts.
    
    Returns:
    
    The encoding scale factor 1x, 2x, or 4x, per the requested encoding type.
  - free
```
public void free()
```
    Free the resources used by this object.
    
    Overrides:
    
    free in class SensorBase
  - getRaw
```
public int getRaw()
```
    Gets the raw value from the encoder. The raw value is the actual count unscaled by the 1x, 2x, or 4x scale factor.
    
    Returns:
    
    Current raw count from the encoder
  - get
```
public int get()
```
    Gets the current count. Returns the current count on the Encoder. This method compensates for the decoding type.
    
    Specified by:
    
    get in interface CounterBase
    
    Returns:
    
    Current count from the Encoder adjusted for the 1x, 2x, or 4x scale factor.
  - reset
```
public void reset()
```
    Reset the Encoder distance to zero. Resets the current count to zero on the encoder.
    
    Specified by:
    
    reset in interface CounterBase
  - getPeriod
```
@Deprecated
public double getPeriod()
```
    Deprecated. Use getRate() in favor of this method.
    
    Returns the period of the most recent pulse. Returns the period of the most recent Encoder pulse in seconds. This method compensates for the decoding type.
    Warning: This returns unscaled periods and getRate() scales using value from setDistancePerPulse().
    
    Specified by:
    
    getPeriod in interface CounterBase
    
    Returns:
    
    Period in seconds of the most recent pulse.
  - setMaxPeriod
```
public void setMaxPeriod(double maxPeriod)
```
    Sets the maximum period for stopped detection. Sets the value that represents the maximum period of the Encoder before it will assume that the attached device is stopped. This timeout allows users to determine if the wheels or other shaft has stopped rotating. This method compensates for the decoding type.
    
    Specified by:
    
    setMaxPeriod in interface CounterBase
    
    Parameters:
    
    maxPeriod - The maximum time between rising and falling edges before the FPGA will report the device stopped. This is expressed in seconds.
  - getStopped
```
public boolean getStopped()
```
    Determine if the encoder is stopped. Using the MaxPeriod value, a boolean is returned that is true if the encoder is considered stopped and false if it is still moving. A stopped encoder is one where the most recent pulse width exceeds the MaxPeriod.
    
    Specified by:
    
    getStopped in interface CounterBase
    
    Returns:
    
    True if the encoder is considered stopped.
  - getDirection
```
public boolean getDirection()
```
    The last direction the encoder value changed.
    
    Specified by:
    
    getDirection in interface CounterBase
    
    Returns:
    
    The last direction the encoder value changed.
  - getDistance
```
public double getDistance()
```
    Get the distance the robot has driven since the last reset as scaled by the value from setDistancePerPulse(double).
    
    Returns:
    
    The distance driven since the last reset
  - getRate
```
public double getRate()
```
    Get the current rate of the encoder. Units are distance per second as scaled by the value from setDistancePerPulse().
    
    Returns:
    
    The current rate of the encoder.
  - setMinRate
```
public void setMinRate(double minRate)
```
    Set the minimum rate of the device before the hardware reports it stopped.
    
    Parameters:
    
    minRate - The minimum rate. The units are in distance per second as scaled by the value from setDistancePerPulse().
  - setDistancePerPulse
```
public void setDistancePerPulse(double distancePerPulse)
```
    Set the distance per pulse for this encoder. This sets the multiplier used to determine the distance driven based on the count value from the encoder. Do not include the decoding type in this scale. The library already compensates for the decoding type. Set this value based on the encoder's rated Pulses per Revolution and factor in gearing reductions following the encoder shaft. This distance can be in any units you like, linear or angular.
    
    Parameters:
    
    distancePerPulse - The scale factor that will be used to convert pulses to useful units.
  - setReverseDirection
```
public void setReverseDirection(boolean reverseDirection)
```
    Set the direction sensing for this encoder. This sets the direction sensing on the encoder so that it could count in the correct software direction regardless of the mounting.
    
    Parameters:
    
    reverseDirection - true if the encoder direction should be reversed
  - setSamplesToAverage
```
public void setSamplesToAverage(int samplesToAverage)
```
    Set the Samples to Average which specifies the number of samples of the timer to average when calculating the period. Perform averaging to account for mechanical imperfections or as oversampling to increase resolution.
    
    Parameters:
    
    samplesToAverage - The number of samples to average from 1 to 127.
  - getSamplesToAverage
```
public int getSamplesToAverage()
```
    Get the Samples to Average which specifies the number of samples of the timer to average when calculating the period. Perform averaging to account for mechanical imperfections or as oversampling to increase resolution.
    
    Returns:
    
    SamplesToAverage The number of samples being averaged (from 1 to 127)
  - setPIDSourceType
```
public void setPIDSourceType(PIDSourceType pidSource)
```
    Set which parameter of the encoder you are using as a process control variable. The encoder class supports the rate and distance parameters.
    
    Specified by:
    
    setPIDSourceType in interface PIDSource
    
    Parameters:
    
    pidSource - An enum to select the parameter.
  - getPIDSourceType
```
public PIDSourceType getPIDSourceType()
```
    Description copied from interface: PIDSource
    
    Get which parameter of the device you are using as a process control variable.
    
    Specified by:
    
    getPIDSourceType in interface PIDSource
    
    Returns:
    
    the currently selected PID source parameter
  - pidGet
```
public double pidGet()
```
    Implement the PIDSource interface.
    
    Specified by:
    
    pidGet in interface PIDSource
    
    Returns:
    
    The current value of the selected source parameter.
  - setIndexSource
```
public void setIndexSource(int channel)
```
    Set the index source for the encoder. When this source is activated, the encoder count automatically resets.
    
    Parameters:
    
    channel - A DIO channel to set as the encoder index
  - setIndexSource
```
public void setIndexSource(DigitalSource source)
```
    Set the index source for the encoder. When this source is activated, the encoder count automatically resets.
    
    Parameters:
    
    source - A digital source to set as the encoder index
  - setIndexSource
```
public void setIndexSource(int channel,
                           Encoder.IndexingType type)
```
    Set the index source for the encoder. When this source rises, the encoder count automatically resets.
    
    Parameters:
    
    channel - A DIO channel to set as the encoder index
    
    type - The state that will cause the encoder to reset
  - setIndexSource
```
public void setIndexSource(DigitalSource source,
                           Encoder.IndexingType type)
```
    Set the index source for the encoder. When this source rises, the encoder count automatically resets.
    
    Parameters:
    
    source - A digital source to set as the encoder index
    
    type - The state that will cause the encoder to reset
  - getSmartDashboardType
```
public java.lang.String getSmartDashboardType()
```
    Live Window code, only does anything if live window is activated.
    
    Specified by:
    
    getSmartDashboardType in interface Sendable
    
    Returns:
    
    The type of this Sendable.
  - initTable
```
public void initTable(ITable subtable)
```
    Description copied from interface: Sendable
    
    Initializes a table for this Sendable object.
    
    Specified by:
    
    initTable in interface Sendable
    
    Parameters:
    
    subtable - The table to put the values in.
  - getTable
```
public ITable getTable()
```
    Description copied from interface: Sendable
    
    The table that is associated with this Sendable.
    
    Specified by:
    
    getTable in interface Sendable
    
    Returns:
    
    the table that is currently associated with the Sendable.
  - updateTable
```
public void updateTable()
```
    Description copied from interface: LiveWindowSendable
    
    Update the table for this sendable object with the latest values.
    
    Specified by:
    
    updateTable in interface LiveWindowSendable
  - startLiveWindowMode
```
public void startLiveWindowMode()
```
    Description copied from interface: LiveWindowSendable
    
    Start having this sendable object automatically respond to value changes reflect the value on the table.
    
    Specified by:
    
    startLiveWindowMode in interface LiveWindowSendable
  - stopLiveWindowMode
```
public void stopLiveWindowMode()
```
    Description copied from interface: LiveWindowSendable
    
    Stop having this sendable object automatically respond to value changes.
    
    Specified by:
    
    stopLiveWindowMode in interface LiveWindowSendable

Class Encoder

Nested Class Summary

Nested classes/interfaces inherited from interface edu.wpi.first.wpilibj.CounterBase

Field Summary

Fields inherited from class edu.wpi.first.wpilibj.SensorBase

Constructor Summary

Method Summary

Methods inherited from class edu.wpi.first.wpilibj.SensorBase

Methods inherited from class java.lang.Object

Field Detail

m_aSource

m_bSource

m_indexSource

Constructor Detail

Encoder

Encoder

Encoder

Encoder

Encoder

Encoder

Encoder

Encoder

Encoder

Encoder

Method Detail

getFPGAIndex

getEncodingScale

free

getRaw

get

reset

getPeriod

setMaxPeriod

getStopped

getDirection

getDistance

getRate

setMinRate

setDistancePerPulse

setReverseDirection

setSamplesToAverage

getSamplesToAverage

setPIDSourceType

getPIDSourceType

pidGet

setIndexSource

setIndexSource

setIndexSource

setIndexSource

getSmartDashboardType

initTable

getTable

updateTable

startLiveWindowMode

stopLiveWindowMode