EncoderDriver.EncoderDriver Class Reference

Encoder Driver Class More...

Public Member Functions
def	__init__ (self, pinA, pinB, timer, PPC, CPR, gearRatio)
	Encoder class constructor More...
def	update (self)
	Update encoder position More...
def	getPosition (self)
	Return encoder position More...
def	getAngle (self)
	Return encoder angle More...
def	setPosition (self, newPosition)
	Set current relative encoder position More...
def	getDelta (self)
	Calculate delta between encoder updates More...
def	tick2rad (self, ticks)
	Convert encoder ticks to degrees More...
def	getSpeed (self, interval)
	Convert encoder delta to degrees per second More...

Public Attributes
	pinA
	Translates the encoder pin A input into Encoder object.
	pinB
	Translates the encoder pin B input into Encoder object.
	tim
	Defines the timer which applies to pins A and B.
	curr_count
	Constructs channel for pin A within timer. More...
	prev_count
	Creates a variable to hold the previous position count of the encoder.
	position
	Creates a local variable to hold the total position of the encoder.
	delta
	Creates a local variable to hold value representing difference between current and previous position.
	PPC
	Define the pulses per cycle for this encoder object via user input into constructor.
	CPR
	Define the cycles per revolution for this encoder object via user input into constructor.
	gearRatio
	Define the gear ratio (motor:encoder) reduced to an integer via user input into the constructor.
	overflow
	Defines total number of counter values before overflow.

Detailed Description

Encoder Driver Class

Constructor & Destructor Documentation

__init__()

def EncoderDriver.EncoderDriver.__init__	(		self,
			pinA,
			pinB,
			timer,
			PPC,
			CPR,
			gearRatio
	)

Encoder class constructor

This method constructs the Encoder object by assigning pin and timer input parameters and defining initial states of pins

Parameters

pinA	The pin location for + encoder terminal. must be properly defined as a pin object before being input into an encoder class. Use pinA = pyb.Pin.cpu. [pin letter(s) and number]
pinB	The pin location for GND encoder terminal. must follow same format for pinA
timer	The timer number which applies to both pins, which can be found using Table 17 of the Nucleo datasheet
PPC	The pulses per rotation of the encoder
CPR	The cycles per rotation of the encoder
gearRatio	The gear ratio between the motor and the output shaft on which the encoder is mounted

Member Function Documentation

getAngle()

def EncoderDriver.EncoderDriver.getAngle

(

self

)

Return encoder angle

Returns

angle Returns the current angular position of the encoder in radians

getDelta()

def EncoderDriver.EncoderDriver.getDelta

(

self

)

Calculate delta between encoder updates

Calculates the difference between the current and previous position counts

Returns

delta Returns the correct difference between current and previous encoder positions in ticks

getPosition()

def EncoderDriver.EncoderDriver.getPosition

(

self

)

Return encoder position

Returns

position Returns the current position of encoder in encoder ticks

getSpeed()

def EncoderDriver.EncoderDriver.getSpeed	(		self,
			interval
	)

Convert encoder delta to degrees per second

Determines the angular velocity of the motor according to the encoder PPC (pulses per cycle), CPR (cycles per revolution), and gear ratio which were input into the object constructor, as well as the time interval over which the encoder delta was calculated.

Parameters

interval

The interval of time over which delta occurs, which must be in seconds

Returns

speed Returns the speed of the encoder in deg/s

setPosition()

def EncoderDriver.EncoderDriver.setPosition	(		self,
			newPosition
	)

Set current relative encoder position

Sets the encoder position according to the desired user input parameter 'angle'

Parameters

newPosition

The angle to which the encoder will be set. must be an integer

tick2rad()

def EncoderDriver.EncoderDriver.tick2rad	(		self,
			ticks
	)

Convert encoder ticks to degrees

Converts the position of the encoder from ticks to degrees

Parameters

ticks

The position or delta of the encoder in ticks. This is most easily obtained from the self.position attribute for position or self.getDelta() method for position delta

Returns

rad Returns the position or delta in radians

update()

def EncoderDriver.EncoderDriver.update

(

self

)

Update encoder position

Updates the encoder position after a set time interval

Member Data Documentation

curr_count

EncoderDriver.EncoderDriver.curr_count

Constructs channel for pin A within timer.

Constructs channel for pin B within timer

Creates a variable to hold the current position count of the encoder

---

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

• EncoderDriver.py