<s>
A	O
linear	B-Algorithm
encoder	I-Algorithm
is	O
a	O
sensor	O
,	O
transducer	B-Algorithm
or	O
readhead	O
paired	O
with	O
a	O
scale	O
that	O
encodes	O
position	O
.	O
</s>
<s>
Linear	B-Algorithm
encoder	I-Algorithm
technologies	O
include	O
optical	O
,	O
magnetic	O
,	O
inductive	O
,	O
capacitive	O
and	O
eddy	O
current	O
.	O
</s>
<s>
Linear	B-Algorithm
encoders	I-Algorithm
are	O
used	O
in	O
metrology	O
instruments	O
,	O
motion	O
systems	O
,	O
inkjet	O
printers	O
and	O
high	O
precision	O
machining	O
tools	O
ranging	O
from	O
digital	O
calipers	O
and	O
coordinate	O
measuring	O
machines	O
to	O
stages	O
,	O
CNC	O
mills	O
,	O
manufacturing	O
gantry	O
tables	O
and	O
semiconductor	O
steppers	B-Algorithm
.	O
</s>
<s>
Linear	B-Algorithm
encoders	I-Algorithm
are	O
transducers	B-Algorithm
that	O
exploit	O
many	O
different	O
physical	O
properties	O
in	O
order	O
to	O
encode	O
position	O
:	O
</s>
<s>
Optical	O
linear	B-Algorithm
encoders	I-Algorithm
dominate	O
the	O
high	O
resolution	O
market	O
and	O
may	O
employ	O
shuttering/moiré	O
,	O
diffraction	O
or	O
holographic	B-Algorithm
principles	O
.	O
</s>
<s>
Optical	B-Algorithm
encoders	I-Algorithm
are	O
the	O
most	O
accurate	O
of	O
the	O
standard	O
styles	O
of	O
encoders	O
,	O
and	O
the	O
most	O
commonly	O
used	O
in	O
industrial	O
automation	O
applications	O
.	O
</s>
<s>
When	O
specifying	O
an	O
optical	B-Algorithm
encoder	I-Algorithm
,	O
it	O
's	O
important	O
that	O
the	O
encoder	O
have	O
extra	O
protection	O
built	O
in	O
to	O
prevent	O
contamination	O
from	O
dust	O
,	O
vibration	O
and	O
other	O
conditions	O
common	O
to	O
industrial	O
environments	O
.	O
</s>
<s>
Interpolation	B-Algorithm
can	O
provide	O
resolutions	O
as	O
fine	O
as	O
a	O
nanometer	O
.	O
</s>
<s>
Magnetic	O
linear	B-Algorithm
encoders	I-Algorithm
employ	O
either	O
active	O
(	O
magnetized	O
)	O
or	O
passive	O
(	O
variable	O
reluctance	O
)	O
scales	O
and	O
position	O
may	O
be	O
sensed	O
using	O
sense-coils	O
,	O
Hall	O
effect	O
or	O
magnetoresistive	O
readheads	O
.	O
</s>
<s>
With	O
coarser	O
scale	O
periods	O
than	O
optical	B-Algorithm
encoders	I-Algorithm
(	O
typically	O
a	O
few	O
hundred	O
micrometers	O
to	O
several	O
millimeters	O
)	O
resolutions	O
in	O
the	O
order	O
of	O
a	O
micrometer	O
are	O
the	O
norm	O
.	O
</s>
<s>
Capacitive	O
linear	B-Algorithm
encoders	I-Algorithm
work	O
by	O
sensing	O
the	O
capacitance	O
between	O
a	O
reader	O
and	O
scale	O
.	O
</s>
<s>
Maxon	O
makes	O
an	O
example	O
(	O
rotary	B-Algorithm
encoder	I-Algorithm
)	O
product	O
(	O
the	O
MILE	O
encoder	O
)	O
.	O
</s>
<s>
There	O
are	O
two	O
main	O
areas	O
of	O
application	O
for	O
linear	B-Algorithm
encoders	I-Algorithm
:	O
</s>
<s>
Servo	O
controlled	O
motion	O
systems	O
employ	O
linear	B-Algorithm
encoder	I-Algorithm
so	O
as	O
to	O
provide	O
accurate	O
,	O
high-speed	O
movement	O
.	O
</s>
<s>
Typical	O
applications	O
include	O
robotics	O
,	O
machine	O
tools	O
,	O
pick-and-place	O
PCB	O
assembly	O
equipment	O
;	O
semiconductors	O
handling	O
and	O
test	O
equipment	O
,	O
wire	B-Algorithm
bonders	I-Algorithm
,	O
printers	O
and	O
digital	O
presses	O
.	O
</s>
<s>
Linear	B-Algorithm
encoders	I-Algorithm
can	O
have	O
analog	O
or	O
digital	O
outputs	O
.	O
</s>
<s>
The	O
industry	O
standard	O
,	O
analog	O
output	O
for	O
linear	B-Algorithm
encoders	I-Algorithm
is	O
sine	O
and	O
cosine	O
quadrature	O
signals	O
.	O
</s>
<s>
The	O
overall	O
accuracy	O
of	O
the	O
linear	B-Algorithm
encoder	I-Algorithm
is	O
a	O
combination	O
of	O
the	O
scale	O
accuracy	O
and	O
errors	O
introduced	O
by	O
the	O
readhead	O
.	O
</s>
<s>
A	O
linear	B-Algorithm
incremental	I-Algorithm
encoder	I-Algorithm
has	O
two	O
digital	O
output	O
signals	O
,	O
A	O
and	O
B	O
,	O
which	O
issue	O
quadrature	O
squarewaves	O
.	O
</s>
<s>
In	O
the	O
latter	O
case	O
,	O
the	O
interpolation	B-Algorithm
process	O
effectively	O
sub-divides	O
the	O
scale	O
period	O
and	O
thereby	O
achieves	O
higher	O
measurement	O
resolution	O
.	O
</s>
<s>
The	O
output	O
signals	O
may	O
be	O
directly	O
transmitted	O
to	O
a	O
digital	O
incremental	B-Algorithm
encoder	I-Algorithm
interface	O
for	O
position	O
tracking	O
.	O
</s>
<s>
The	O
major	O
advantages	O
of	O
linear	B-Algorithm
incremental	I-Algorithm
encoders	I-Algorithm
are	O
improved	O
noise	O
immunity	O
,	O
high	O
measurement	O
accuracy	O
,	O
and	O
low-latency	O
reporting	O
of	O
position	O
changes	O
.	O
</s>
<s>
As	O
well	O
as	O
analog	O
or	O
digital	O
incremental	O
output	O
signals	O
,	O
linear	B-Algorithm
encoders	I-Algorithm
can	O
provide	O
absolute	O
reference	O
or	O
positioning	O
signals	O
.	O
</s>
<s>
Most	O
incremental	O
,	O
linear	B-Algorithm
encoders	I-Algorithm
can	O
produce	O
an	O
index	O
or	O
reference	O
mark	O
pulse	O
providing	O
a	O
datum	O
position	O
along	O
the	O
scale	O
for	O
use	O
at	O
power-up	O
or	O
following	O
a	O
loss	O
of	O
power	O
.	O
</s>
<s>
The	O
reference	O
mark	O
may	O
comprise	O
a	O
single	O
feature	O
on	O
the	O
scale	O
,	O
an	O
autocorrelator	O
pattern	O
(	O
typically	O
a	O
Barker	B-Protocol
code	I-Protocol
)	O
or	O
a	O
chirp	B-Application
pattern	O
.	O
</s>
<s>
Many	O
linear	B-Algorithm
encoders	I-Algorithm
include	O
built-in	O
limit	O
switches	O
;	O
either	O
optical	O
or	O
magnetic	O
.	O
</s>
<s>
Linear	B-Algorithm
encoders	I-Algorithm
may	O
be	O
either	O
enclosed	O
or	O
open	O
.	O
</s>
<s>
Enclosed	O
linear	B-Algorithm
encoders	I-Algorithm
are	O
employed	O
in	O
dirty	O
,	O
hostile	O
environments	O
such	O
as	O
machine-tools	O
.	O
</s>
<s>
For	O
the	O
highest	O
accuracy	O
,	O
lowest	O
measurement	O
hysteresis	O
and	O
lowest	O
friction	O
applications	O
,	O
open	O
linear	B-Algorithm
encoders	I-Algorithm
are	O
used	O
.	O
</s>
<s>
Linear	B-Algorithm
encoders	I-Algorithm
may	O
use	O
transmissive	O
(	O
glass	O
)	O
or	O
reflective	O
scales	O
,	O
employing	O
Ronchi	O
or	O
phase	O
gratings	O
.	O
</s>
