RPS-3000PVC & RPS-4000 Ultrasonic Level Sensor

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RPS-3000PVC, RPS-4000 Features
SimpleCalibration Non-Contact TemperatureComp.
Analog4-20mAOutput SensitivityControl
Self-Contained LEDIndicator QuickDisconnect Aff
ordability Microprocessor Design
Easy Installation Theseself-containedUltrasonic
Sensors provide level control
of bothliquidandbulkmaterials. This
gives the user a viable alternative to
bubblers, floats, capacitance probes, and
pressure transmitters. With sensing ranges of
30 and 40 feet respectively many
tanks arewithinreach. Theirincorpora- tion of
a microprocessor design makesitpossibletoachiev
esignal conditioning. Thisgivesthesensor the
ability to process the return ultrasonic
echo and distinguish between false targets and
real tar- gets. Migatron Corporation - 1997
With the incorporation of
a microcontroller into the design of
the RPS-3000PVC and RPS-4000 many of the common
problems facing long range sensing applications
have been overcome. Softwarewasthenwritten to
optimize the performance characteristic
s of the sensors. The artificial
intelligence analyzes and conditions the
return ultrasonic echo. Thisprocessfiltersoutanyf
alseechoes and electrical noise. An
additional task that the microcontroller does
is temperature compensation. 3000/4000 -
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The following is a brief list of features for the
RPS- 3000PVCandRPS-4000. SIMPLE CALIBRATION
The sensing window can be adjusted by using one
of three easy methods. NOTE Whenthesensorsarepo
weredupandthecontrollinesnot used, they are
factory preset to maximum range. NON-CONTACT
Theuseofultrasonicsoundtomeasure distancemeansthat
thesensordoesnotneedtocomein contact with the
target. TEMPERATURE COMPENSATED
Thisisaccomplished by means of a temperature
probe that is built into the transducerhead. ANAL
OG OUTPUT These sensors provide a
4-20mA analogoutputthatisproportionaltothechanging
distance. Thisoutputcanbeinverted. SENSITIVITY
CONTROL This enables the gain of
the sensortobeadjustedtoworkbestindifferenttanksan
don differentmaterials. EASY INSTALLATION Both
of these sensors are con- tained in a standard
30mm housing. They come with two jam-nutsforsimpl
emounting.
HOW TO CALIBRATE MethodOne(andpossiblythemostdi
rectwaytocalibrate the sensing range) is as
follows (see figure B) Step 1 Tie the Red/Yel
wire (20mA control line) and the Red/Bluewire(4mAc
ontrolline)together. Step 2 With the material
level at the 4mA point, usually thelowlevel,connec
t theselinestoground(Greenwire)for onesecond. Ste
p3 Withthemateriallevelatthe20mApoint,usually the
highlevel, connecttheselinestoplus(Redwire)forone
second. Thesensorisnowcalibratedandwillgenerateth
eanalog 4-20mAoutputbetweenthesetwopoints. NOTE
When completed, the two control lines
should remaintiedtogether. Tochangethewindow,
disconnect thesetwowiresforonesecondandthenreconne
ctthem. Thenrepeatsteps2and3. Thefarpointshouldalw
aysbe programmedfirst,thenthenearpoint. MethodTwo
calibratesthesensorsbyusingthefollowing charts(see
figureC)
RPS-3000PVC Sensing Red/Blue
Red/Yel Window Wire Wire
RPS-4000 Red/Blue Wire
SELF-CONTAINED Therearenoremoteboxestomount with
these sensors. All necessary electronics are
con-
Red/Yel Wire
Sensing Window
tained within the sensor. LED INDICATOR This
indicates the detect state of the sensor as well
as the strength of the return echo.
This featurehelpstoinsureproperalignmentduringinst
allation. AFFORDABILITY These sensors were
designed to be cost competitive and to solve
applications. MICROPROCESSOR DESIGN The
incorporation of a
2'-30' 2'-27' 2'-24' 2'-21' 2'-18' 2'-15' 2'-12' 2
' - 9' 2' - 6'
OPEN OPEN OPEN LOW LOW LOW HIGH HIGH HIGH
OPEN LOW HIGH OPEN LOW HIGH OPEN LOW HIGH
OPEN OPEN OPEN LOW LOW LOW HIGH HIGH HIGH
OPEN LOW HIGH OPEN LOW HIGH OPEN LOW HIGH
2'-40' 2'-36' 2'-32' 2'-28' 2'-24' 2'-20' 2'-16' 2
'-12' 2' - 8'
Open This indicates that the control line is
not tied to anything. It is left floating.
microprocessor allowed software to be written to
solve manyofthecommonproblemsthatneededtobeovercom
e
withlongrangeapplications. High The control
line is tied to plus (Red Wire). Low The
control line is tied to ground (Green
Wire). When using these charts to
calibrate the sensors the analogoutputwilloccu
roverthefullrangeoftheselected sensingwindow.
The20mAwillbeattheneardistanceand the 4mA will
be at the far distance. One advantage of
calibrating the sensors this way is that there
is no need to fill the tank to the high and low
limits. Anotheradvantageisthatoncethesensorisinst
alledthere isnoneedtogobacktoittoprogram.
Thiscanbedoneat a remote location at the end of
the sensor's cable.
Migatron Corporation - 1997
3000/4000
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target, the gain can be reduced to see if the
false target disappears. LED INDICATOR TheLEDis
locatedatthebackofthesensor. Itprovidesby wayofcol
orvariousindicationastothesensor'sfunctions. Its
primary purpose is to insure proper alignment
during installation. The following colors
indicate Green Thesensorhaspowerandisintheno-de
tectstate. Yellow Thesensorhasdetectedatargetbut
isreceiving a weak signal. It may be that the
sensor is not properly alignedtothematerialorthatt
hetargetisprovidingaweak returnecho. Red
Thisindicatesthatthesensorisdetectingthetarget. Th
ebrightertheshadeofredthestrongerthereturnecho. Th
isindicatesthesensorisproperlyalignedandthetarget
isprovidingagoodreflectivesurface. NOTE It may
not always be possible to get a bright
red signal. Thisisbecausevariousmaterialswillhaved
ifferent reflectivitycharacteristics.
However,aslongasthesensor stays in the yellow to
red state, enough return signal
is beingreceivedandthesensorwillfunctionproperly.
ANALOG OUTUT TheRPS-3000PVCandRPS-4000provideana
nalogcur- rent output of 4-20mA. This output is
proportional to the changingdistancethathasbeenpro
grammed. Theoutput load rating of the sensors are
0 to 500 ohms. QUICK DISCONNECT CONNECTOR At
the rear of the sensor, there is a water
tight quick disconnectconnector.
Thisallowsthesensortobeeasily removedfromthetanksh
ouldthisbedesired. MICROPROCESSOR DESIGN The
RPS-3000PVC and RPS-4000 long range
ultrasonic sensors incorporate a high speed
microcontroller/micro- processor. Software
was then written to optimize the performance
characteristics of the sensors. This
artifical intelligence analyzes and conditions
the return ultrasonic echo. Thisprocessfiltersouta
nyfalseechosandelectrical noise. An additional
task that the microcontroller does
is temperaturecompensation. Thisallowsthesensortoh
ave amoreaccurateoutputovervaryingtemperaturerange
s. Thuswiththeincorporationofamicrocontrollermanyo
fthe commonproblemsfacinglongrangesensingapplicati
ons havebeenovercome.
Method Three calibrates the sensors by using
resistors tiedtothecontrollines(seefigureD).
Theseresistorsare installedbetweenthecontrollinesa
ndground(greenwire). Thefollowingresistanceformula
appliesfordistance 1Kohm 1 foot. Forexample
ifarangeof5'to15'isdesiredwithananalog outputof20m
Aat5',and4mAat15',thefollowingresistor valuesshoul
dbeselected 15' 15Kohm resistor tied to 4mA
control line (Red/Blue) 5'5Kohmresistortiedto20mA
controlline(Red/Yellow) The output will now
start at 5' 20mA and decrease with distance to
15' 4mA. The output can be scaled in
the oppositedirectionbyreversingthevalues 5'
5Kohm resistor tied to 4mA control line
(Red/Blue) 15' 15Kohm resistor tied to 20mA
control line (Red/Yel) The output now starts
at 5' 4mA and increases with distance to 15'
20mA. Potentiometerscanbeusedinplaceoffixedresist
orsand then the proper distances can be dialed
in. Theadvantagewiththismethod,aswiththesecondway
of calibrating, is that the tank does not need to
be filled to its highandlowlimitsduringsetup.
Inadditionthesesetpoints can be adjusted at a
later time without going to the top of the
tank. HOW TO USE THE GAIN CONTROL The
RPS-3000PVC and RPS-4000 sensors provide
the userwithgaincontrol. ThisiscontrolledbytheRed/
White wire(seefigureE). Whenthiswireisleftopen(flo
ating)the sensors are operating at their maximum
sensitivity. The sensor's gain can be reduced by
doing the following Install a 100Kohm
potentiometer or a fixed value resistor across
the gain control line (Red/White wire) and
ground (Greenwire). Withthepotentiometersetat100Ko
hm,the gain or sensitivity of the sensor is at
its maximum. When thepotentiometerissetat75Kohm,t
hesensitivityis75 offullgain. Ifthepotentiometeri
sturnedallthewaydown whichisequivalenttoshortingth
egainwiretoground,the sensor is at minimum
sensitivity. Thesensitivity/gaincontrolallowsthes
ensortobeadjusted to work best in different tanks
and on different materials. This control does not
need to be used. If the sensor
is installedandworkswellwithfullsensitivitythereis
noneed to reduce the gain. However if the sensor
is installed and itseemstobedetectingsomethingothe
rthenthedesired
Migatron Corporation - 1997
3000/4000
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Specifications Operational Range RPS-3000PVC
Adjustable 2' to 30' RPS-4000 Adjustable 2'
to 40' Power Input 20 - 30 VDC Reverse
Polarity Protected Input Current 125 Milliamps
The angle of tilt of a flat target is
plus andminus10degrees.
The Beam Spread is approximately 20 degrees.
This is equal to 4.25" per foot.
Ambient Temperature Humidity Enclosure
-20ºC to 60ºC or -5ºF to 140ºF 0 - 95
Non-Condensing RPS-3000PVC Epoxy filled
PVC housing with PVC sensing face.
20 CORRECT
20 CORRECT
RPS-4000 Epoxy filled PVC housing with Glass
Reinforced Epoxy sensing face.
Outputs
Current Sourcing Analog Output 4 - 20mA Inverted
Non-Inverted Short Circuit Protected
Transducer Frequency
RPS-3000PVC
PRS-4000
38Khz
41Khz
20
20
Transmit Time
This equals the sensors maximum distance x
10mSec. For example if the maximum
programmed distance is 10' the transmit time is
100mSec. 15 ounces
CORRECT
INCORRECT
Fig. A
Weight
RED20-30VDC GREEN GROUND RED/BLK
4-20mA RED/WHT GAIN CONTROL RED/BLU4mACONTROLLI
NE RED/YEL 20mA CONTROL LINE Fig. E
RED20-30VDC GREEN GROUND RED/BLK
4-20mA RED/WHT GAIN CONTROL RED/BLU4mACONTROLLI
NE RED/YEL 20mA CONTROL LINE Fig. D
RED20-30VDC GREEN GROUND RED/BLK
4-20mA RED/WHT GAIN CONTROL RED/BLU4mACONTROLLI
NE TAP HIGH LOW RED/YEL 20mA CONTROL
LINE Fig. B
RED20-30VDC GREEN GROUND RED/BLK
4-20mA RED/WHT GAIN CONTROL RED/BLU4mACONTROLLI
NE TIEHIGH,LOW,OROPEN RED/YEL 20mA CONTROL
LINE TIEHIGH,LOW,OROPEN Fig. C
6.625" Thread M30 x 1.5
Figure A-Installation/BeamSpread B-WiringDiag.fo
rprogrammingmethod1
1 2
5 4
6
3 1. Red-Wt. Tr 2. Red 3. Green 4. Red-Yl. Tr
C-WiringDiag.forprogrammingmethod2 D-WiringDiag.f
orprogrammingmethod3 E-WiringDiag.forgaincontrol
2.750"
5. Red-Bk. Tr 6. Red-Blu. Tr Fig. F
F-ConnectorDiagram(MaleView) G-MountingDimensions
"QD"cablesaresoldseparately.
Fig. G
PARTNUMBER RANGE DESCRIPTION
RPS-3000PVC 2'to30' PVCHousingwithPVCSensingFace
RPS-4000 2'to40' PVCHousingwithGlassReinforcedEpoxySensingFace
5000127-2 5000127-4 6'Cablewith"QD" 16'Cablewith"QD"
[phone] / FAX [phone]
Dieckman Rd., Woodstock, Il. 60098
USA http//www.migatron.com e-mail
info_at_migatron.com
Migatron Corp.
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