drivers.Encoder.Encoder Class Reference

A Quadrature Encoder class to be used with the ME 405 test bench. More...

Public Member Functions
def	__init__ (self, ch_A, ch_B, Timer timer, position=0)
	Constructor for the Encoder object. More...
def	update (self)
	Update the current position and the last position. More...
def	get_position (self, units="pulses")
	Get the current encoder position. More...
def	set_position (self, position, units="pulses")
	Set the current encoder position. More...
def	get_delta (self)
	Get the change in encoder position (in pulses) since last update.

Public Attributes
	ch_A
	Channel A.
	ch_B
	Channel B.
	enc
	The timer channel to poll which collects encoder counts.
	timer
	The Timer that tracks the encoder.
	last_count
	The previous pulse count.
	position
	The current absolute position as a count of pulses.
	PPR
	The pulse rate (Pulses Per Revolution).

Detailed Description

A Quadrature Encoder class to be used with the ME 405 test bench.

Supports encoder polling at a frequency of up to 65536pps

Constructor & Destructor Documentation

__init__()

def drivers.Encoder.Encoder.__init__	(		self,
			ch_A,
			ch_B,
		Timer	timer,
			position = 0
	)

Constructor for the Encoder object.

Parameters

ch_A	Pin on channel A
ch_B	Pin on channel B
timer	A Timer that will be used to track the encoder
position	An optional initial position

Member Function Documentation

get_position()

def drivers.Encoder.Encoder.get_position	(		self,
			units = "pulses"
	)

Get the current encoder position.

Returns

Return the current position in the specified units. If none are specified (or they are unrecognized) return the current position in pulses.

Parameters

units

The units to return. Supported units: pules - The number of edges (timer counts) cycles - The number of cycles for a quadrature encoder (cycles = pulses / 4) degrees - The total angle in degrees radians - The total angle in degrees revolutions - The total number of revolutions

set_position()

def drivers.Encoder.Encoder.set_position	(		self,
			position,
			units = "pulses"
	)

Set the current encoder position.

Returns

Return the current position in the specified units. If none are specified (or they are unrecognized) return the current position in pulses.

Parameters

position	The new value of the encoder position.
units	The units to return. Supported units: pules - The number of edges (timer counts) cycles - The number of cycles for a quadrature encoder (cycles = pulses / 4) degrees - The total angle in degrees radians - The total angle in degrees revolutions - The total number of revolutions

update()

def drivers.Encoder.Encoder.update

(

self

)

Update the current position and the last position.

Update the current position and the last position. Assumes that the encoder is updated at least once every half period of the timer and handles the overflow associated. Thus any counter value above half the period is assumed to be a backwards rotation.

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

• labFF/drivers/Encoder.py