Eqep - Texas Instruments TMS320F2837 D Series Workshop Manual And Lab Manual

eQEP

What is an Incremental Quadrature
Incremental Optical Encoder
The eQEP module interfaces with a linear or rotary incremental encoder for determining position,
direction, and speed information from a rotating machine that is typically found in high-
performance motion and position-control systems.
(A,B) =
Ch. A
Ch. B
TMS320F2837xD Microcontroller Workshop - Control Peripherals
Encoder?
A digital (angular) position sensor
θ
photo sensors spaced /4 deg. apart
θ
slots spaced deg. apart
light source (LED)
shaft rotation
How is Position Determined from
Quadrature Signals?
Position resolution is
(00) (11)
(10) (01)
θ
Ch. A
Ch. B
Quadrature Output from Photo Sensors
θ
/4 degrees
increment
counter
10
Illegal
Transitions;
00
generate
phase error
interrupt
01
Quadrature Decoder
State Machine
eQEP
θ
/4
decrement
counter
11
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