4-20SC-MaxSonar
®
-WR
™
Series
4-20SC-MaxSonar -WR/WRC™ Series
High Resolution, Precision, IP67 Weather Resistant, Ultrasonic Range
Finders
MB7760, MB7769, MB7780, MB7789
4
®
The 4-20SC-MaxSonar-WR sensor line is a high performance ultrasonic precision
rangefinder that provides high accuracy, high resolution ultrasonic range detection in air.
The 4-20SC-MaxSonar-WR sensor line includes an effective self-cleaning capability
designed to reduce the impact of condensation in closed or high-moisture (dew, frost, etc.)
environments and is a cost-effective solution for automation/process control applications
where precision range-finding, low-voltage operation, space saving, low cost and IP67
weather resistance is needed. This sensor component allows users of other more costly
precision rangefinders to lower the cost of their systems without sacrificing performance. The sensor output works with
existing PLC equipment and is also suitable for applications with long cable runs. The 4-20SC-MaxSonar-WR/WRC
sensor line features 1.6-mm resolution, superior rejection of outside noise sources, internal speed-of-sound temperature
compensation and optional external speed-of-sound temperature compensation. The sensors are factory calibrated to
provide stable and reliable range readings. With a maximum range of 5 meters, these ultrasonic sensors detect objects
from 5-mm and ranges to objects from 50-cm to maximum range. Objects closer than 50-cm are typically reported as 50-
cm (See Close Range Operation).
Precision Ultrasonic Range
Sensing
Easy to Use Component
•
Robust and easy to use interface
•
Excellent noise rejection
•
A fraction of the cost of other
•
Small and easy to mount
precision rangefinders
•
Factory-matched accuracy provides a
•
Stable, reliable range readings
•
Target size compensation provides
typical accuracy of 1% or better of
1
greater consistency and accuracy
distance to target
•
Auto handles acoustic noise
1,3
•
Reading-to-reading stability of
•
Calibrated sensor eliminates most
1.6-mm at 1-meter is typical
1
sensor-to-sensor variations
•
Compensation for target size
variation and operating voltage range
General Characteristics
•
Temperature compensation is
•
4-20mA with ~1.6mm resolution
standard
•
Refresh rate of ~0.60Hz
•
Additional chemical resistance
•
Determines range to largest object
available
2
(MB7769, MB7789)
Low Power Requirements
•
Determines range to first detectable
•
Average power draw of ~70mA
object (MB7760, MB7767, MB7780,
MB7787)
•
Other interfaces (non4-20mA)
available with lower current draw
•
Excellent clutter rejection
•
Flexible, low supply voltage
•
Low-cost ultrasonic rangefinder
requirements simplifies battery
•
Resolution of ~1.6-mm
powered designs
•
Distance from 50-cm to 5-meters
•
Low current draw reduces current
•
Excellent MTBF of > 200,000 hrs.
drain for battery operation
•
Superior noise rejection
4
•
Operating temperature range
from -40°C to +65°C
•
Operating voltage from 10V to 32V
•
IP67 rated
Applications & Uses
•
•
•
•
•
•
•
•
•
•
Automated process control systems
Tank level measurement
Weather station monitoring
Bin level measurement
Corn level measurement
1
Proximity zone detection
People detection
Robot ranging
Long range object detection
Environments with acoustic and
electric noise
•
Height monitors
•
Auto sizing
•
Box dimensions
Notes
Users to evaluate the sensor performance
F-Option provides added protection from hazardous
chemical environments
3
By design
4
Please reference page 12 for part number key
2
1
Close Range Operation
Applications requiring 100% reading-to-reading reliability should not use MaxSonar sensors at a distance closer than
50cm. Although most users find MaxSonar sensors to work reliably from 0 to 50cm for detecting objects in many
applications, MaxBotix
®
Inc. does not guarantee operational reliability for objects closer than the minimum reported
distance. Because of ultrasonic physics, these sensors are unable to achieve 100% reliability at close distances.
_______________________________________________________________________________________________________________________________________
Warning: Personal Safety Applications
We do not recommend or endorse this product be used as a component in any personal safety applications. This product is
not designed, intended or authorized for such use. These sensors and controls do not include the self-checking redundant
circuitry needed for such use. Such unauthorized use may create a failure of the MaxBotix
®
Inc. product which may result
in personal injury or death. MaxBotix
®
Inc. will not be held liable for unauthorized use of this component.
MaxBotix
®
Inc.
Copyright 2005 - 2014 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA.
Page 1
Web:
www.maxbotix.com
PD13441d
4-20SC-MaxSonar
®
-WR
™
Series
4-20SC-MaxSonar-WR/WRC General Operation
The 4-20SC-MaxSonar-WR ultrasonic sensors are in-air, non-contact, object detection and ranging sensors that detect
objects within an area. These sensors are not affected by the color or other visual characteristics of the detected object.
Ultrasonic sensors use high frequency sound to detect and localize objects in a variety of environments. Ultrasonic sensors
measure the time of flight for sound that has been transmitted to and reflected back from nearby objects. Based on the
time of flight, the sensor outputs a distance value.
4-20 Sensor Connection Pin Out
Pin 6 —
Ground return for the DC power supply.
The black wire will be for the cable attach.
Pin 5 —
4-20mA signal output, the analog current output has a resolution of ~1.6mm.
The brown wire will be for the cable attach.
Pin 4 —
Vcc input. This sensor has an operational input voltage of 10V to 32V DC. This
sensor has a nominal current draw of less than 40mA.
The red wire will be for the cable attach.
Pin 1
Temperature Sensor Connections
Pin 3
— Temperature sensor V+ source. This is the red connection wire on the HR-MaxTemp sensors.
Pin 2
— Temperature sensor input. This is the white connection wire on the HR-MaxTemp sensors.
Pin 1
— Temperature sensor shield.
_______________________________________________________________________________________________________________________________________
Output Conversion Equations
Formulas to convert the sensor output are to distance provided below for convenience.
Using I (mA) as the output current and d (mm) as the distance.
Distance
MB776X
MB778X
d = (((I - 4) * 4500) / 16) + 500
d = 5000 - (((I - 4) * 4500) / 16)
Current
I = (((d - 500) * 16) / 4500) + 4
I = (((5000 - d) * 16) / 4500) + 4
_______________________________________________________________________________________________________________________________________
Scaling the 4-20mA to a 5V or 10V Analog Voltage
The 4-20SC-MaxSonar-WR sensor output can be easily scaled at the user end to match
the voltage range of an existing PLC or microcontroller system equipped with an
analog to digital converter by using the schematic shown to the right.
For 5V data use a resistor value of 250 ohms 0.1% — when using this resistor value
the sensor requires a minimum of 15VDC for proper operation and runs with a voltage
range of 1V to 5V.
For 10V data use a resistor value of 500 ohms 0.1% — when using this resistor value
the sensor
requires a minimum of 19VDC
for proper operation and runs with a
voltage range of 2V to 10V.
Custom products with analog voltage outputs are also available from MaxBotix Inc.
Formulas to convert the sensor output to distance are provided below for convenience.
Using V (volts) as the output voltage and d (mm) as the distance.
Distance
5V
5V
MB776X
MB778X
d = (((V - 1) * 4500) / 4) + 500
d = 5000 - (((V - 1) * 4500) / 4)
d = (((V - 2) * 4500) / 8) + 500
d = 5000 - (((V - 2) * 4500) / 8)
Voltage
V = (((d - 500) * 4) / 4500) + 1
V = (((5000 - d) * 4) / 4500) + 1
V = (((d - 500) * 8) / 4500) + 2
V = (((5000 - d) * 8) / 4500) + 2
Page 2
Web:
www.maxbotix.com
PD13441d
10V MB776X
10V MB778X
MaxBotix
®
Inc.
Copyright 2005 - 2014 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA.
4-20SC-MaxSonar
®
-WR
™
Series
About Ultrasonic Sensors
The 4-20SC-MaxSonar-WR ultrasonic sensors are in-air, non-contact object detection and ranging sensors that detect
objects within an area. These sensors are not affected by the color or other visual characteristics of the detected object.
Ultrasonic sensors use high frequency sound to detect and localize objects in a variety of environments. Ultrasonic sensors
measure the time of flight for sound that has been transmitted to and reflected back from nearby objects. Based upon the
time of flight, the sensor outputs a range reading.
_______________________________________________________________________________________________________________________________________
Base Sensor (MB7760 & MB7780)
The MB7760 and MB7780 sensors are the base models of the 4-20SC-MaxSonar-WR sensor line. These general purpose
sensors are recommended unless specific requirements indicate other sensors may be a better fit for the application. All
other sensors in this series are based off of these sensor models. The additional features are mentioned in their respective
sections below.
_______________________________________________________________________________________________________________________________________
4-20SC-MaxSonar-WRM (MB7769 & MB7789)
The 4-20SC-MaxSonar-WRM sensors comes with the self-cleaning and most-likely filter features.
In general, the 4-20SC-MaxSonar-WRM sensors will select the largest target from its field of view and report its range.
Even so, objects up close may provide significantly greater returns over distant objects. Users are encouraged to test the
sensor in their application to verify usability.
4-20SC-MaxSonar-WRM sensors should not be used in multiple sensor operation.
MaxBotix recommends choosing the 4-20SC-MaxSonar-WRM sensors for applications that are in high-moisture
environments, or which are vulnerable to occasional condensation. These sensors are IP67 rated, so water or ice will not
damage the sensor.
_______________________________________________________________________________________________________________________________________
Self-Cleaning Description
The 4-20SC-MaxSonar-WR sensors feature a self-cleaning protocol which gently heats the face of the transducer, and
atomizes any moisture or condensation on the sensor’s transducer face. This feature allows the sensor to be used in a wide
variety of applications that may experience condensation issues. Self-cleaning is needed for many such applications due to
detection performance limitations resulting from condensation, including only reporting the minimum or maximum
reported distance.
Condensation is frequently an issue in tanks because the sensor is typically mounted at the top of the tank, above a
warmer liquid. On clear nights or cold nights, this causes the sensor hardware to be colder than its surrounding
environment, causing condensation to build up on the surface of the exposed sensor hardware. This can also occur in some
buildings, depending on climate control.
The reason that condensation affects sensors is fairly straightforward. Sensors determine distance to targets, even if that
target is on the surface of the transducer. Targets (condensation, solid particles, etc.) on the transducer face will impede
sensor operation. These targets will either be detected or cause a reduction in the sensitivity of the sensor. The self-
cleaning operation is designed to prevent and remove buildup of moisture from the surface of the transducer. For proper
self-cleaning, the sensor must remain on, and continue normal ranging operation.
The self-cleaning feature is only designed for moisture, not removal of dust or other solid particles. Multiple sensor
operation is not possible with the self-cleaning 4-20SC-MaxSonar-WR sensors.
MaxBotix
®
Inc.
Copyright 2005 - 2014 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA.
Page 3
Web:
www.maxbotix.com
PD13441d
4-20SC-MaxSonar
®
-WR
™
Series
About Package Types
The 4-20SC-MaxSonar-WR sensors are available in a variety of packages for applications with specific mounting
requirements. The full horn package provides peak accuracy and sensitivity in this sensor line. It is recommended that
testing is completed to ensure that the selected sensor will operate as desired in your application.
Package Types Currently Available
Full Horn –
3/4” NPT straight; back mounted thread
(best performance)
Compact –
3/4” NPT straight; back mounted thread
1”NPS – External thread over full sensor body (1”NPS)
1”BSPP – External thread over full sensor body (1”BSPP)
30mm1.5 – External thread over full sensor body (30mm1.5)
All package types have exposed PCB on user end for easy connection.
Users desiring a fully enclosed assembly may purchase the “Shielded
Cable Option” along with their sensor.
_______________________________________________________________________________________________________________________________________
Performance Changes when Selecting a Non-Full Horn Package
When selecting a 4-20SC-MaxSonar-WR sensor without the full horn the sensor will experience the following
performance changes:
•
•
•
•
•
The sensor will have a wider beam shape for the first meter.
The sensor may be less accurate by an additional +/- 0.5%.
The sensor may have a dead zone from 0mm
–
500mm.
The sensor may have worse performance to small or soft targets.
The sensor may experience decreased noise immunity when ranging to small, soft, angled, or distant targets.
_______________________________________________________________________________________________________________________________________
Range Zero Location
In general, the 4-20SC-MaxSonar-WR sensors report the range to the leading edge of the closest detectable object. Target
detection is characterized in the sensor beam patterns.
The 4-20SC-MaxSonar-WR reports the range to distant targets from where the threading and nut meet on the sensor
housing as shown in the diagrams below.
Range Zero
0.0 mm
The range is measured from where the housing meets the threading.
Target Face
Range Zero
0.0 mm
The range is measured from the front of the sensor.
Target Face
MaxBotix
®
Inc.
Copyright 2005 - 2014 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA.
Page 4
Web:
www.maxbotix.com
PD13441d
4-20SC-MaxSonar
®
-WR
™
Series
Mechanical Dimensions Continued
3/4” National Pipe Thread Straight
A
B
C
D
E
F
G
H
I
J
K
L
M
2.87”
72.9 mm
1.72” dia. 43.8 mm dia.
0.31”
7.9 mm
0.58”
14.4 mm
2.00”
50.7 mm
0.31”
7.9 mm
0.10”
2.54 mm
3/4” NPS
1.37” dia. 34.8 mm dia.
1.03” dia. 26.2 mm dia.
0.41”
10.3 mm
0.78”
19.81 mm dia.
0.62”
15.76 mm
weight, 1.89 oz., 53.5 grams
A
C
D
F
Pin 1
B
G
H
E
I
J
K
Pin 1
L M
values are nominal
1” National Pipe Thread Straight
A
C
Pin 1
B
E
D
A
B
C
D
E
F
G
H
I
F
1.58”
40.2 mm
1.29” dia.
33.0 mm dia.
0.27”
7.0 mm
1.30”
33.1 mm
0.10”
2.54 mm
1” NPS
0.40”
10.3 mm
0.78”
19.81 mm
0.62”
15.76 mm
weight, 1.28 oz., 36.3 grams
G
Pin 1
H I
values are nominal
1” BSPP Mechanical Dimensions
A
C
Pin 1
B
E
D
A
B
C
D
E
F
G
H
I
F
1.58”
40.2 mm
1.29” dia.
33.0 mm dia.
0.27”
7.0 mm
1.30”
33.1 mm
0.10”
2.54 mm
1” BSPP
0.40”
10.3 mm
0.78”
19.81 mm
0.62”
15.76 mm
weight, 1.26 oz., 35.6 grams
G
Pin 1
H I
values are nominal
30mm 1.5 Mechanical Dimensions
A
C
Pin 1
B
E
D
A
B
C
D
E
F
G
H
I
F
1.58”
40.2 mm
1.17” dia.
29.7 mm dia.
0.27”
7.0 mm
1.24”
31.5 mm
0.10”
2.54 mm
30mm 1.5
0.40”
10.3 mm
0.78”
19.81 mm
0.62”
15.76 mm
weight, 1.14 oz., 32.4 grams
G
Pin 1
H I
values are nominal
MaxBotix
®
Inc.
Copyright 2005 - 2014 MaxBotix Incorporated
Patent 7,679,996
MaxBotix Inc., products are engineered and assembled in the USA.
Page 5
Web:
www.maxbotix.com
PD13441d
