
Agilent HEDR-542x Miniature
Reflective Optical Encoder
Product Brief
Introduction
Agilent’s optical encoders are
used in a variety of motion
control applications to provide
position, velocity and direction
sensing.
About the Products
The HEDR-542x is an easy-to-
mount, high-performance,
reliable, two-channel encoder.
The HEDR-542x offers a resolu-
tion of 200 counts per revolution,
featuring typically less than
15 electrical degrees pulse width
error (PWE) and less than 30 elec-
trical degrees for combined phase
and state width error.
The HEDR-542x is ideal for
equipment using small and
miniaturized motors, operating
within the 0oC to +85oC tempera-
ture range, and operating from a
5-volt supply.
Product Mechanism
HEDR-542x encoders translate the
rotary motion of a shaft into a
two-channel digital quadrature
output. The light emitted from a
LED is focused onto a reflective
codewheel. As the shaft moves, the
codewheel rotates, reflecting light
from an alternating bright and
dark pattern. The transitions are
detected by a photodetector IC.
Features and Benefits
• PWE <15 degrees
SWE <30 degrees
– Accurate system control
• Small footprint
– Saves space on PCB; can be
used in small motor system
where space is a constraint
• Cost effective solution
– Value added at low cost
• Several mounting options are
available
– Press fit, set screw and mount-
ing ears to suit design and size of
motors
• Easy assembly
– Shortens assembly time
Typical Applications
• Vending machines
• Volumetric dispenser
• Card readers
(automated teller machines)
• Robotics
• Security camera controls
• Paper feed control
(office automation)