enc_driver.EncDriver Class Reference

An encoder driver object. More...

Public Member Functions
def	__init__ (self, ID, Pin1, Ch1, Pin2, Ch2, tim_no, CPR, debug)
	Creates an encoder object. More...
def	update (self)
	Updates the encoder. More...
def	get_position (self, units)
	Returns the encoder position in desired units. More...
def	set_position (self)
	Sets the encoder position to a specified value in ticks. More...
def	get_delta (self, units)
	Returns the current encoder delta in desired units. More...
def	get_ddelta (self)
	Returns the current encoder delta delta in ticks. More...
def	convert (self)
	Uses the raw encoder count values to calculate encoder position & delta in other units. More...
def	trace (self)
	Prints a trace output when called. More...

Public Attributes
	ID
	The unique ID string for the object, used for trace output. More...
	debug
	A boolean that toggles the trace output to the command line. More...
	tim
	The timer objct that is used to read the encoder. More...
	conv_deg
	Conversion factor ticks -> degrees. More...
	conv_rad
	Conversion factor ticks -> radians. More...
	pos
	The current position of the encoder. More...
	prev_pos
	The previous position of the encoder. More...
	delta
	The difference between the current position and the previous position. More...
	prev_delta
	The previous delta of the encoder. More...
	ddelta
	The difference between the current delta and the previous delta. More...
	last_count
	Previous encoder count. More...
	t1
	Ticks value 1. More...
	t2
	Ticks value 2 from counter. More...
	pos_deg
	Encoder position in degrees. More...
	pos_rad
	Encoder position in radians. More...
	delta_deg
	Encoder delta in degrees. More...
	delta_rad
	Encoder delta in radians. More...

Detailed Description

An encoder driver object.

This class configures hardware, to monitor an encoder's position. The encoder ticks are counted using a timer object, and the timer is queried to get updated position values. The diver class corrects timer overflow errors, and is able to handle encoder rotation CW and CCW.

Constructor & Destructor Documentation

__init__()

def enc_driver.EncDriver.__init__	(		self,
			ID,
			Pin1,
			Ch1,
			Pin2,
			Ch2,
			tim_no,
			CPR,
			debug
	)

Creates an encoder object.

Parameters

ID	A string identifying the object for traceing output.
Pin1	The pin object that will be bound to encoder channel A
Ch1	The timer channel for the first pin
Pin2	The pin object that will be bound to encoder channel B
Ch2	The timer channel for the second pin
tim_no	The timer number that will be used to read the encoder
CPR	Encoder's cycles per revolution
debug	A boolean that toggles the trace output on or off

Member Function Documentation

convert()

def enc_driver.EncDriver.convert

(

self

)

Uses the raw encoder count values to calculate encoder position & delta in other units.

get_ddelta()

def enc_driver.EncDriver.get_ddelta

(

self

)

Returns the current encoder delta delta in ticks.

get_delta()

def enc_driver.EncDriver.get_delta	(		self,
			units
	)

Returns the current encoder delta in desired units.

get_position()

def enc_driver.EncDriver.get_position	(		self,
			units
	)

Returns the encoder position in desired units.

set_position()

def enc_driver.EncDriver.set_position

(

self

)

Sets the encoder position to a specified value in ticks.

trace()

def enc_driver.EncDriver.trace

(

self

)

Prints a trace output when called.

update()

def enc_driver.EncDriver.update

(

self

)

Updates the encoder.

This function passes the position from the last call to the prev_pos atribute, calculates a new delta value, corrects the delta value, and updates the encoder position.

Member Data Documentation

conv_deg

enc_driver.EncDriver.conv_deg

Conversion factor ticks -> degrees.

conv_rad

enc_driver.EncDriver.conv_rad

Conversion factor ticks -> radians.

ddelta

enc_driver.EncDriver.ddelta

The difference between the current delta and the previous delta.

debug

enc_driver.EncDriver.debug

A boolean that toggles the trace output to the command line.

delta

enc_driver.EncDriver.delta

The difference between the current position and the previous position.

delta_deg

enc_driver.EncDriver.delta_deg

Encoder delta in degrees.

delta_rad

enc_driver.EncDriver.delta_rad

Encoder delta in radians.

ID

enc_driver.EncDriver.ID

The unique ID string for the object, used for trace output.

last_count

enc_driver.EncDriver.last_count

Previous encoder count.

pos

enc_driver.EncDriver.pos

The current position of the encoder.

pos_deg

enc_driver.EncDriver.pos_deg

Encoder position in degrees.

pos_rad

enc_driver.EncDriver.pos_rad

Encoder position in radians.

prev_delta

enc_driver.EncDriver.prev_delta

The previous delta of the encoder.

prev_pos

enc_driver.EncDriver.prev_pos

The previous position of the encoder.

t1

enc_driver.EncDriver.t1

Ticks value 1.

t2

enc_driver.EncDriver.t2

Ticks value 2 from counter.

tim

enc_driver.EncDriver.tim

The timer objct that is used to read the encoder.

The prescaler is set to zero and the period is set to 0xFFFF or 65535

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

• me405 Term Project/enc_driver.py