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The digital temperature sensor
of DS18B20
The
digital
temperature
sensor
of
DS18B20,
This
product
uses
the
American
DALLAS company's
DS18B20 network digital temperature sensor chip
package. but
become
wear-
resistant
touch,
the
physical
volume
is
small,
convenient,
packaging
form is varied , Suitable for all kinds
of narrow space in digital temperature test and
control field equipment.
Unique
1-Wire
TM
interface
requires
only
one
port
pin
for
communication.
Multidrop
capability simplifies distributed temperature
sensing applications, requires
no
external components, Can be powered from data
line. Power supply range is 3.0V
to
5.5V, Zero standby power required, Measures
temperatures from -55°
C
to+125°
C.
Fahrenheit
equivalent
is
-67°
F
to+257°
F,
?
0.5
?
C
accuracy
from
-10°
C
to
+85°
C,
Thermometer
resolution
is
programmable
from
9
to
12
bits,
Converts
12-bit
temperature to
digital word in750 ms (max.).User-definable,
nonvolatile temperature
alarm
settings,
Alarm
search
command
identifies
and
addresses
devices
whose
temperature
is
outside
of
programmed
limits
(temperature
alarm
condition).Applications
include
thermostatic
controls,
industrial
systems,
consumer
products, thermometers, or any
thermally sensitive system.
1
、
the description
of
technique function:
1)
Single-line
interface is unique, DS18B20 while linking with
microprocessor only
need
a
line
can
immediately
carry
out
the
double
of
microprocessor
and
DS18B20 toward the
communication.
2)
measure scope-55
℃
~ +125
℃
, proper measure
resolution's 0.5
℃
.
3)
support
several
set
nets
function,
several
DS18B20
can
merge
at
unique
three
on-line,
the
most
can
merge
8,
if
amount
was
excessive,
it
would
make
power
supply the power
electric
voltage over low, result in
thus the
signal
delivers of
unsteady,
the realizations order to measure more
4)
work the
power:3~5V|DC
5)
don't need any outer circle component
in the use
6)
measure the result measure a way string
with 9~12 numbers line transmission
7)
stainless
steels protect to take care of diameter
Φ
6
8)
be applicable to DN15~25, DN40~ DN250
various equipments that lie industrial
piping of quality and narrow and small
space measure
9)
standards install the thread M10 X1,
M12 X1.5, the G 1|2 term chooses
10)
PVC electric
cable direct the line or virtuous type ball type
connect line box line,
the easy to and
other electric appliances equipments links.
2
、
Application
1)
products
are
applicable
to
cold
storage,
food
Cang,
keep
a
bottle,
tele-communications
engine
room,
electric
power
engine
room,
cable
slot
etc.
measures moderate control realm
2)
stalk
tiles,
urn
body,
the
Fang
machine,
the
air
condition,
waits
industrial
equipments of
narrow and small space to measure a moderate
control.
3)
car
air condition, refrigerator, cold cabinet, and
medium low temperature dry box
of
etc.s.
4)
provide
hot|make
cold
piping
calories
to
calculate,
the
central
air
condition
divides
a
thermal
energy
to
calculate
to
measure
a
moderate
control
with
industrial realm
3
、
Product model
number and specification
type
TS-18B20
TS-18B20A
TS-18B20B
4
、
Connect line
instruction
The
characteristics
special
front
line
connects,
needs
a
line
to
correspond
by
letter to order more ability and
simplified a distribute type the temperature
spread the
feeling
application
didn't
need
an
external
component
to
use
data
total
line
power
supply,
the
electric
voltage
scope
has
never
needed
to
provide
for
use
the
power
diagraph temperature
scope for the 3.0-5.5 Vs BE-55
℃
to+125
℃
.The Fahrenheit is
equal hence-67-257 Fahrenheit degree-10
℃
go to+85
℃
accuracy inside the scope
is
±
0.5
℃
The temperature
spreads a feeling machine's programmable
resolution to convert
into
12
number
formats
for
9~12
temperatures
biggest
be
worth
to
750
a
milli-
of
second the customer can
define of not and easily lose sex temperature to
report to the
police to establish an
application to include a constant temperature
control, industrial
system, consume
electronics product thermometer, or any hot
sensitive system
The
number
thermometer
that
describes
the
DS18B20
provides
9-12(the
programmable
equipments temperature read a number. The
information is disheveled
hair to send
to connect through a line from the DS18B20, so
central microprocessor
and
DS18B20
only
have
a
per
line
conjunction.
For
read
and
write
and
the
temperature
conversion
can
acquire
energy
from
the
data
line,
don't
need
to
temperature range
install
thread
-55~125
-55~125
-55~125
no
M10X1
1/2G
electric
cable length
apply piping
1.5 m
1.5m
Connects
line box
DN15~25
DN40~ 60
circumscribe the power. Because each
DS18B20 includes
a special ordinal
number,
several ds 18 bs 20
seses can be existed to a total line at the same
time. This makes
the temperature spread
a feeling machine to place in many different
places. Its use is a
lot
of,
include
an
air
condition
environment
control,
detect
equipments
inside
the
building or machine, and
carry on process monitor and control.
The DS18B20 internal structure mainly
constitutes to from the four-part cent: 64
temperatures that only engrave ROM and
temperature to spread a feeling machine and
don't vaporize report to the police to
trigger a machine TH and TL and allocation to
deposit
a
machine.
While
equiping
signal
line
Gao,
the
internal
capacitor
stores
an
energy
from a line and corresponds by letter circuit to
the film power supply, and at
low
electricity even period for film power supply
until next Gao Dian Ping's arrival
refreshes .The power of the DS18B20 can
also.5V electric voltages get from 3 Vs-5s
in the exterior.
The
DS18B20
adopts
front
line
correspondence
to
connect.
Because
the
front
line
correspondence
connects,
have
to
previously
complete
ROM
enactment,
otherwise
memory
and
control
function
will
can
not
use.
Mainly
provide
following
function to order any first of a:
1)
read ROM
2)
ROM match
3)
search ROM
4)
jump ROM
5)
report to the
police a check.
These instruction
operation the function has no 64 sequences that
only engrave
ROM
of
a
spare
part,
can
be
hanging
several
spare
parts
on
the
front
line
to
make
selection a certain
spare part, at the same time, the total line can
also know always
on-line hang how much,
what kind of equipments.
If
the
instruction
successfully
makes
the
DS18B20
completion
temperature
measure,
the
data
saves
in
the
saving
machine
of
performance
of
a
control
function
conductor
designation
DS18B20
measures.
Measure
result
will
be
placed in the DS18B20 memories, and can
let reading to send out the conductor of
remembering
the
function,
reading
contents
of
slice
ascend
saving
machine.
The
temperature reports to the police to
trigger machine TH and TLs to all have one word
stanza
EEPROM
data.
If
DS18B20
not
the
use
report
to
the
police
to
check
instruction, these deposit a machine to
be a general customer to remember use. Still
carry to there
is allocation word's the stanza converting by
ideal solution temperature
number on
the slice. Write TH, TL instruction and allocation
word stanza makes use
of instruction
completion that remembers function. Pass to slowly
save a machine to
read to deposit a
machine. All datas read writing all a beginning
from the lowest.
The DS18B20 has 4 main
data parts:
1
、
only engrave 64
sequences in ROM are what factory front be only
engraved likes, it
can see make the
address sequence that is the DS18B20 code.64
alignments that only
engrave ROM are:
Starting 8(28 Hs) is the product type mark number,
immediately
after
of
48
sequences
that
is
the
DS18
B20
oneself,
last
8
is
56
front
circulating
redundancy schools to check code.(CRC=X
8+ Xs 5+ Xs 4+s 1)The function that only
engraves
ROM
is
to
make
each
DS18B20
all
each
not
same,
so
can
carry
out
a
purpose that is always on-
line to hang to connect several DS18 B20s.
2
、
the temperature
in the DS18B20 spread a feeling machine to
complete the diagraph
to
the
temperature
and
take
12
conversions
as
an
example:
The
binary
system
expanding
with
16
signs
repairs
code
to
read
to
count
a
form
to
provide,
with
0.0625
℃
|the LSB form express,
among them, the S is a sign.
The saving
machine of DS18B20 includes high speed to
temporary save machine
RAM and can give
or get an electric shock to wipe in addition to
RAM, can give or
get
an
electric
shock
to
wipe
in
addition
to
RAM
includes
temperature
to
trigger
machine
TH
and
TL
again,
and
an
allocation
deposits
a
machine.
Saving
machine
ability
the
integrity
really
settle
the
communication
of
front-line
port,
the
number
starts
using
to
write
the
order
of
depositing
the
machine
to
write
into
deposit
a
machine, immediately after can
also
use order of reading to
deposit
the
machine to
confirm
these
numbers.
After
confirming
can
use
the
order
that
the
replication
deposits a
machine can give or get an electric shock to wipe
to transfer these numbers
to in
addition to RAM in. While once modifying to
deposit the number in the machine,
this
process can ensure the integrity of number.
The high speed temporary saves machine
RAM to constitute to°
from the saving
machine of 8 word stanzas; The first
and the second word stanza are temperatures to
show. The fourth Sha-ho word stanza is
to make duplicate TH and TL, at the same
time the fourth Sha-ho number of word
stanza can renew; The fifth word stanza is to
make duplicate allocation to deposit a
machine, the fifth number of word stanza can
renew at the same time;6, 7, 8, three
word stanzas are calculator oneself use. Using
reads that the order that deposit a
machine can read the ninth word stanza, this word
stanza is eight
word stanzas to the front to carry on schools to
check.
64 8 ex- oneself codes that is a
DS18B20 that only engrave ROM, next 48 are a
continuous number code, 8 of end is to
56 ex- of the CRC schools check.64-the light
of engrave ROM and include the function
order of 5 ROMs:Read ROM, match ROM,
jump up ROM, check to seek ROM and
report to the police to check to seek.
The
DS18B20
can
use
external
power
VDD
as
well
as
use
the
power
in
the
living on of inner part.
When the VDD port connects the electric voltage
with 3.0 Vs
~Vs-5.5ses
is
use
external
power;
When
the
VDD
port
connects
ground
used
the
power in the living on of inner part.
No matter is an inner part to live on the power or
an external power supply, I|the O line
want to connect a 5 K
Ω
to
or soly and up pull
electric
resistance.
Allocation's depositing a
machine is the conversion that installs different
number
to make sure temperature and
number.
R1, the R0 is the decision of
temperature, from the R1, the different
combination
of
R0
can
install
for
9,
10,
11,
12
temperatures
show.
So
can
know
a
different
temperature
conversion
to
should
of
conversion
time,
four
kinds
of
resolutions
of
allocations
distinguish
to
0.5
℃
,
0.25
℃
,
0.125
℃
and
0.0625
℃
,
factory
take
installing as 12.
DS18B20 at
factory with install for 12, read temperature
totally read 16, so the
empress is 112
enter make to convert into 10 enter make after at
multiply 0.0625 is
then
measure
of
temperature,
also
need
to
be
judged
plus
or
minus.
Front
5
piece
words
are
signs,
current
5
is
1:00,
read
of
temperature
is
minus
quantity;5
is
0:00,
read at
present of temperature is plus quantity.16 numbers
put from low to Gao Wei.
The
instruction agrees on code operating instructions:
1)
The
temperature
converts
the
44
H
start
DS18B20
to
carry
on
a
temperature
conversion
2)
Read to
temporary save machine BEH to read to temporary
save machine 9 word
stanza contentses
3)
Write
temporary and save the machine 4 EHs to write in a
data temporary TH of
saving the machine
and TL word stanza
4)
The
replication
temporary
saves
the
machine
48
Hs
temporary
save
the
TH
of
machine and TL word stanza to write E2
RAM
5)
Re-
adjust
the
E2
RAM
B8's
Hs
write
the
E2
TH
within
RAMs
and
TL
word
stanza to arrive to temporary save
machine TH and TL word stanza and read that
the signal that
the B4 H start DS18B20 of the power supply method
sends out the
power supply method gives
lord CPU
The beginning of DS18B20
starts to turn.
1)
place data line first Gao Dian
Ping
2)
postpone(what the time request isn't
very strict, but possibly a little bit shorter)
3)
the data line
pull a low electricity
even
4)
postpone
750.(the horary time scope can from 480-960)
5)
the data line
pull Gao Dian Ping
6)
wait for while postponing(if is
early to
start
to
become an
achievement then
in
15-60
time
inside
produce
a
low
electricity
that
is
returned
by
the
DS18
B20
even
not be
infinitely carry on waiting for, otherwise will
make procedure get into to
die
circulating, so control while wanting to carry on
to be super).
7)
if CPU read the data is on-line low to
give or get an electric shock even
while
also
needing to
do to
postpone time for it to
postpones from
send out
of
Gao Dian Ping start to
calculate to at least want 480.
8)
pull data line
again Gao Dao Gao to end after giving or getting
an electric shock
is even
As
the
simple
structure,
convenient
installment,
low
loss
and
wide
range
of
temperature
test,
DS18B20
temperature
test
sensors
are
applied
to
the
fields
which
needs
the
multipoint
temperature
test,
such
as
the
chemical
industry,
the
grain,
the
environment
supervision
and
so
on.
Because
of
the
adoption
of
one
bus
in
the
DS18B20 multipoint temperature test
system, all DS18B20 are hung on one bus, and
then
the
temperature
conversion
value
of
each
test
point
is
read
by
turns.
As
the
conversion
value
must
be
read
after
reading-pin
state
for
8
times,
and
position
and
store data must be moved, so time spend
much in reading one point of the data system
by every time. If the temperature test
system is large-scaled, the system loss caused by
it is rather much, and then the
alternate test speed of the system decreases
obviously,
which influences the
efficiency of the multipoint temperature test
system seriously. In
this paper,
DS18B20 are hung on some I/O buses by grouping
DS18B20 evenly, and
the conversion
temperature data is obtained by reading the state
of DS18B20, then the
system loss
decreases and the alternate test speed increases
obviously, which won’t
influence
the
precision
and
the
reliability
of
the
conversion.
A
set
of
multipoint
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