encoderDriverW2.encoder Class Reference

Used to effectively read encoders and relevent information. More...

Public Member Functions
def	__init__ (self, pinA, pinB, timerNumber)
	Initialization for a specific encoder. More...
def	update (self)
	Updates absolute position of encoder. More...
def	get_position (self)
	Simply returns the instantaneous position of the motor.
def	get_delta (self)
	Simply returns the most recent corrected delta value calculated.
def	set_position (self)
	Zeros the position of the rotor.
def	get_timeDif (self)
	Returns the time difference between the two most recent encoder values.
def	get_omega (self)
	Returns the most recently tracked "instantaneous" speed [rad/s] of the rotor.

Public Attributes
	pinA
	Object for input 1 of encoder to be referenced.
	pinB
	Object for input 2 of encoder to be referenced.
	tim
	Clock object that is used to read ChA and ChB from encoder.
	tim_ChA
	Channel object for input 1 for encoder 1.
	tim_ChB
	Channel object cor input 2 for encoder 1.
	deltaValuesList
	Array to carry the two most recent count values to determine delta.
	absolutePosition
	Initial position of motor in ticks.
	timestampValuesList
	Array of timestamps to carry the two most recent count values to determine speed.
	delta
	Initializing the delta value.
	count
	Timer value read from the encoder.
	timeDif
	correctedDelta
	Corrected delta that can be used for capturing absolute poistion.

Detailed Description

Used to effectively read encoders and relevent information.

This encoder class is used to constantly read quadrature encoders to determine absolute position by the update() method. Also, the initialization allows for simultaneous running of other encoders. Other methods allow for easy instantaneous data collection.

Constructor & Destructor Documentation

__init__()

def encoderDriverW2.encoder.__init__	(		self,
			pinA,
			pinB,
			timerNumber
	)

Initialization for a specific encoder.

This initialization method accepts two pins. PinA and PinB represent the pins at which the encoder is connected to the Nucleo. Lastly, timerNumber represents the timer which will collect values from the A & B channels.

Parameters

pinA	pyb.Pin.cpu.### for input 1 of encoder to be referenced.
pinB	pyb.Pin.cpu.### for input 2 of encoder to be referenced.
timerNumber	Number of timer which runs for the specific pins.

Member Function Documentation

update()

def encoderDriverW2.encoder.update

(

self

)

Updates absolute position of encoder.

This method reads the count from the timer to determine the relative position of the encoder. Then, the method compares the updated count to the previous count, to determine a delta value. If the delta value is greater than half the period, case A, we need to correct the delta by subtracting the period. If the delta value is less than half the negative period, case B, we need to correct the delta by adding the period. If the delta is anything else, we can say no correction is needed. Once the method has the corrected delta, it adds it to the previous absolute position.

Returns

absolutePosition A continuous stream of returning the updated absolute position.

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The documentation for this class was generated from the following file:

• encoderDriverW2.py