1
E4A-3K Ultrasonic Reflective Sensor
Sensor with an Adjustable Sensing
Distance of 0.3 to 3 m Under Stable
Operation without Background
Interference
■Ensures a stable operating range with minimal
side-lobe areas.
■Built-in unstable operation check function allows
easy adjustment to a proper mounting direction.
■Mono-block construction with a sensor, power
supply, and terminals ensures easy wiring.
■Incorporates synchronous selector and reference
pulse I/O terminals ideal for parallel-operation use
without mutual interference.
Ordering Information
Application Examples
Detection of cellophane, glass, and
photosensitive paper
Detection of objects on conveyors or
discrimination of object heights
Sensing method Reflective
Model for AC E4A-3K
for DC E4A-3K DC12-24
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E4A-3KE4A-3K
Specifications
■Ratings/Characteristics
Note: Models operating at 12 to 24 VDC are available. Specify the supply voltage when ordering.
■Operating and Dead Ranges
An object may be detected due to multiple reflection if the object is in the dead range, in which case however, the detection of the object
will not be stable. Therefore, do not attempt to use the E4A-3K to detect an object in the dead range by making use of multiple reflection.
Note: Multiple reflection is a phenomenon caused by an ultrasonic beam reflected several times repeatedly between the sensing object
and the Sensor or nearby objects such as the ceiling.
Supply voltage 100, 110, 200, and 220 VAC ± 10% at 50/60 Hz (see note)
Power consumption Approx. 2.5 VA
Sensing distance Adjustable between 0.3 and 3 m (selectable ranges of 0.3 and 2 m or 1.3 and 3 m)
Standard sensing object 100-mm dia., 1.5-m-long metal or plastic round pipe
Minimum sensing object 50 x 50 mm flat plate
Ultrasonic oscillation frequency Approx. 40 kHz
Directional angle Half-value angle: 25°
Response time Operate time: 0.25 s; release time: 0.5 s
Control output Contact output: SPDT
3 A at 220 VAC, cos dia.=1 or 3 A at 24 VDC, cos dia.=1
Ambient temperature Operating: –20°C to 55°C (with no icing)
Ambient humidity Operating: 45% to 85%
Insulation resistance 20 MΩ min. (at 500 VDC)
Dielectric strength 1,500 VAC, 50/60 Hz for 1 min
Vibration resistance Destruction: 10 to 25 Hz, 1.5-mm double amplitude for 2 hrs each in X, Y, and Z directions
Shock resistance Destruction: 500 m/s2 (approx. 50G) 3 times each in ±X, ±Y, and ±Z directions
Life expectancy
(output relay)
Mechanical 20,000,000 operations min.
Electrical 100,000 operations min.
Enclosure rating IEC IP60
Weight Approx. 500 g without Mounting Bracket
Approx. 600 g with Mounting Bracket
1. Distance Selector Set to a Range Between 0.3 and 2 m 2. Distance Selector Set to a Range Between 1.3 and 3 m
Sensor
Reference level
A: Sensing distance
B: Sensing zone
Dead range
Operating range: 0.5 m
The distance from the reference level to the operating range (detection zone).
Sensor
Reference level
A: Sensing distance Dead range
Operating range: 1.5 m
The distance from the reference level to the operating range (detection zone).
B: Sensing zone
The sensing distance (A) is adjust-
able with the distance selector to a
range between 0.3 and 2 m.
If the sensing distance (A) is set to 2 m,
the sensing zone (B) is 1.5 to 2 m.
If the sensing distance (A) is set to 0.3 m,
the sensing zone (B) is 0 to 0.3 m.
The sensing distance (A) is adjusta-
ble with the distance selector to a
range between 1.3 and 3 m.
If the sensing distance (A) is set to 3 m,
the sensing zone (B) is 1.5 to 3 m.
If the sensing distance (A) is set to 1.3 m,
the sensing zone (B) is 0 to 1.3 m.
3
E4A-3KE4A-3K
Engineering Data
■Operating Zone (Typical Examples)
The operating zone is the sensing range of the E4A-3K at the sensing distance with the sensing object moved vertically towards the ultra-
sonic beam. The operating zone varies with the sensing distance and sensing object.
Reference
• Each of the following illustrations indicates the operating zone
with the E4A-3K mounted to the ceiling for the purpose of detect-
ing the human body. In either case, make sure that the lower limit
of the sensing range is approximately 0.5 m above the floor so
that the floor will not be detected.
Typical Example
• If more than one Unit is used within a maximum distance of 8 m,
be sure to wire the Units so that the Units will be in synchronous
operation. Refer to External Connections for details.
• If there is a door between two Units located for different operat-
ing zones as shown in the following illustration, be sure to wire
the Units so that the Units will be in synchronous operation.
Distance (cm) Distance (cm)
Distance (cm)
Sensing object :
100 dia. x 1,000 (mm)
Sensing object:
200 x 200 (mm)
flat plate
Sensing object :
25 dia. x 100 (mm)
Operating
zone (cm)
Ultrasonic
Sensor
Operating
zone (cm)
Operating
zone (cm)
Ultrasonic
Sensor
Operating
zone (cm)
Operating
zone (cm)
Ultrasonic
Sensor
Operating
zone (cm)
Sensing distance
2 m
450 mm
550 mm
600 mm
750 mm
3 m
Approx. 0.5 m
Approx. 0.5 m
Distance selector set to a range
between 1.3 and 3 m.
Sensing distance
(operating zone)
= Approx. 1.5 m
Sensing distance
(operating zone)
= Approx. 1.5 m
8 m max.
Senso
r
Door
4
E4A-3KE4A-3K
Dimensions
Note: All units are in millimeters unless otherwise indicated.
Installation
■External Connections
E4A-3K
Rubber cap
Indicator
Mounting Dimensions
Two, 6.5 dia.
6.6 dia.
24 dia.
Example of Connections of the E4A-3K in Synchronous Operation
Contact output
100/110 VAC
200/220 VAC
Contact output
100/110 VAC
200/220 VAC
Contact output
100/110 VAC
200/220 VAC
Example of Connections of the E4A-3K
in Asynchronous Operation
Note: 1. If the synchronous operation of the
E4A-3K is not required, set the
reference pulse selector to ON.
Keep terminals 7 and 8 open.
2. Use a cable with an external
diameter of 10 mm max. for wiring.
Note: 1. If the synchronous operation of the E4A-3K is required, set the reference
pulse selector of only one Unit to ON. Then connect terminal 7 of all the Units
together and do the same for terminal 8.
2. A maximum of 50 Units can be connected in synchronous operation.
3. Do not wire the lines for synchronous operation use (i.e., wires connecting to
terminals 7 and 8) alongside power lines in the same conduit.
4. Use a shielded cable with an external diameter of 10 mm max. for wiring.
5. Make sure that all the Units in synchronous operation are turned on,
otherwise none of the Units will operate.
5
E4A-3KE4A-3K
Adjustments
Reference Pulse Selector Position
If more than one Unit is used at one location, the Units will need
to be in synchronous operation to prevent mutual interference. In
that case, set the reference pulse selector of only one Unit to ON.
Set the reference pulse selector of each Unit to ON if the Units
are in asynchronous operation. Refer to External Connections for
details.
Sensing Distance Adjustments
Before adjusting the sensing distance, remove the rubber cap
from the top of the E4A-3K. Be sure to put on the rubber cap after
the sensing distance is adjusted.
1. Apply a flat-blade screwdriver to the groove of the distance
selector to set the distance selector to either a range
between 0.3 and 2 m or a range between 1.3 and 3 m
according to the desired sensing distance and operating
range.
2. To set the sensing distance, first locate a flat plate as a
sensing object that is approximately 20-by-20 cm at the
desired sensing distance. Then gradually turn the sensing
distance adjuster clockwise (i.e., in the direction increasing
the sensing distance) until the relay operates. The opera-
tion indicator will be lit when the relay operates.
Standard Sensing Distance Settings
• If the sensing object is moving vertically towards the ultrasonic
beam (i.e., the E4A-3K is in normal sensing operation), set the
sensing distance so that the sensing side of the object passes
through the center of the operating range as shown in the follow-
ing illustration.
If there is an object, such as a floor, wall, or conveyor, located
behind the sensing object, make sure that the distance between
the set sensing distance (d) and the background object is 0.1d
min. Furthermore, make sure that the set sensing distance (d) is
at least 0.1d closer to the Sensor from the maximum limit of the
operating range as shown in the following illustration.
From the above, the minimum height (h) of the sensing object is
expressed by 0.2d. If the sensing object is comparatively low in
height or if the E4A-3K is used for the delicate height discrimina-
tion of objects, it will be necessary to set the sensing distance to a
small value.
• If the sensing object is moving parallel to the ultrasonic beam for
level or height detection, the sensing distance will be the dis-
tance required for the sensing object to move.
Operation Check
After adjusting the sensing distance, check that the E4A-3K oper-
ates properly by locating the sensing object within the operating
range. Then remove the sensing object and check that the opera-
tion indicator is not lit. The operating indicator may be still be lit or
flashing after the sensing object is removed. In that case, the
E4A-3K may be malfunctioning due to beam reflection from
objects outside the operating range or affected by ambient wind
or temperature, in which case, eliminate the cause or change the
mounting position or direction of the Sensor.
If the mounting position or direction of the Sensor is changed, be
sure to check the sensing distance and the operation of the E4A-
3K.
Operation indicator
Sensing distance adjuster
Distance selector
Reference pulse selector
Sensing distance
Operating range
Sensing side
d
l
Sensing distance
Operating
range
Sensing side
0.1 d min.
0.1 d min.
d
l
Sensing distance
Operating range
d
Operation indicator flashing Operation indicator not li
t
6
E4A-3KE4A-3K
Precautions
■Correct Use
Sensor Mounting Angle
If the E4A-3K is in level control or distance control of sensing
objects, the stability of signal detection will depend on the sensing
surface condition of the objects. Considering the repose angle of
the objects, mount the E4A-3K so that the ultrasonic beam and
the sensing surface of each object meet at right angles to each
other.
Surrounding Objects
Make sure that the Sensor is free from surrounding objects that
reflect the ultrasonic beam diffusion, otherwise the Sensor may
malfunction. In particular, pay the utmost attention so that no side
lobe of the ultrasonic beam will be reflected by such objects.
Mounting
Securely mount the E4A-3K by using the nuts provided with the
E4A-3K or the mounting holes of the E4A-3K. Refer to Dimen-
sions for details.
Do not strike the Sensor with any hammer or other object, other-
wise the E4A-3K will no longer be water-resistant.
If the E4A-3K is not mounted securely, the E4A-3K may be dam-
aged by vibration or may not detect sensing objects accurately
due to a possible change in the mounting position.
Environmental Conditions
Do not use the E4A-3K at a temperature exceeding the rated
range or outdoors, otherwise the reliability and life of the E4A-3K
will decrease.
The Ultrasonic Reflective Sensor utilizes the air as a beam trans-
mission media. Do not use the E4A-3K in places with radical con-
vection or extreme local temperature changes. For example, if
there is a hot air curtain that causes turbulence within the sensing
area, the E4A-3K may malfunction.
The jetting sound of air nozzles includes noise of a wide fre-
quency range, which will affect the operation of the E4A-3K. Do
not use an air nozzle near the E4A-3K.
The sensing distance of the E4A-3K will decrease if there is any
water drops on the surface of the emitter or receiver.
The reflective model may not detect any objects if there is any
object absorbing sound, such as powder and cotton, on the sur-
face of the emitter or receiver.
Turbulence Air curtain
E4A-3K
7
E4A-3KE4A-3K
E4A-3KE4A-3K
In the interest of product improvement, specifications are subject to change without notice.
ALL DIMENSIONS SHOWN ARE IN MILLIMETERS.
To convert millimeters into inches, multiply by 0.03937. To convert grams into ounces, multiply by 0.03527.
CSM_E4A-3K_DS_E_3_1
D064-E1
OMRON Corporation
Industrial Automation Company
Sensing Devices Division H.Q.
Application Sensors Division
Shiokoji Horikawa, Shimogyo-ku,
Kyoto, 600-8530 Japan
Tel: (81)75-344-7068/Fax: (81)75-344-7107
Read and Understand This Catalog
Please read and understand this catalog before purchasing the products. Please consult your OMRON representative if you have any questions or
comments.
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WARRANTY
OMRON's exclusive warranty is that the products are free from defects in materials and workmanship for a period of one year (or other period if specified)
from date of sale by OMRON.
OMRON MAKES NO WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED, REGARDING NON-INFRINGEMENT, MERCHANTABILITY, OR
FITNESS FOR PARTICULAR PURPOSE OF THE PRODUCTS. ANY BUYER OR USER ACKNOWLEDGES THAT THE BUYER OR USER ALONE HAS
DETERMINED THAT THE PRODUCTS WILL SUITABLY MEET THE REQUIREMENTS OF THEIR INTENDED USE. OMRON DISCLAIMS ALL OTHER
WARRANTIES, EXPRESS OR IMPLIED.
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OMRON SHALL NOT BE RESPONSIBLE FOR SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES, LOSS OF PROFITS OR COMMERCIAL LOSS
IN ANY WAY CONNECTED WITH THE PRODUCTS, WHETHER SUCH CLAIM IS BASED ON CONTRACT, WARRANTY, NEGLIGENCE, OR STRICT
LIABILITY.
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IN NO EVENT SHALL OMRON BE RESPONSIBLE FOR WARRANTY, REPAIR, OR OTHER CLAIMS REGARDING THE PRODUCTS UNLESS
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SUBJECT TO CONTAMINATION, ABUSE, MISUSE, OR INAPPROPRIATE MODIFICATION OR REPAIR.
Application Considerations
SUITABILITY FOR USE
OMRON shall not be responsible for conformity with any standards, codes, or regulations that apply to the combination of products in the customer's
application or use of the products.
At the customer's request, OMRON will provide applicable third party certification documents identifying ratings and limitations of use that apply to the
products. This information by itself is not sufficient for a complete determination of the suitability of the products in combination with the end product,
machine, system, or other application or use.
The following are some examples of applications for which particular attention must be given. This is not intended to be an exhaustive list of all possible
uses of the products, nor is it intended to imply that the uses listed may be suitable for the products:
Outdoor use, uses involving potential chemical contamination or electrical interference, or conditions or uses not described in this catalog.
Nuclear energy control systems, combustion systems, railroad systems, aviation systems, medical equipment, amusement machines, vehicles,
safety equipment, and installations subject to separate industry or government regulations.
Systems, machines, and equipment that could present a risk to life or property.
Please know and observe all prohibitions of use applicable to the products.
NEVER USE THE PRODUCTS FOR AN APPLICATION INVOLVING SERIOUS RISK TO LIFE OR PROPERTY WITHOUT ENSURING THAT THE
SYSTEM AS A WHOLE HAS BEEN DESIGNED TO ADDRESS THE RISKS, AND THAT THE OMRON PRODUCTS ARE PROPERLY RATED AND
INSTALLED FOR THE INTENDED USE WITHIN THE OVERALL EQUIPMENT OR SYSTEM.
PROGRAMMABLE PRODUCTS
OMRON shall not be responsible for the user's programming of a programmable product, or any consequence thereof.
Disclaimers
CHANGE IN SPECIFICATIONS
Product specifications and accessories may be changed at any time based on improvements and other reasons.
It is our practice to change model numbers when published ratings or features are changed, or when significant construction changes are made.
However, some specifications of the products may be changed without any notice. When in doubt, special model numbers may be assigned to fix or
establish key specifications for your application on your request. Please consult with your OMRON representative at any time to confirm actual
specifications of purchased products.
DIMENSIONS AND WEIGHTS
Dimensions and weights are nominal and are not to be used for manufacturing purposes, even when tolerances are shown.
PERFORMANCE DATA
Performance data given in this catalog is provided as a guide for the user in determining suitability and does not constitute a warranty. It may represent the
result of OMRON’s test conditions, and the users must correlate it to actual application requirements. Actual performance is subject to the OMRON
Warranty and Limitations of Liability.
ERRORS AND OMISSIONS
The information in this document has been carefully checked and is believed to be accurate; however, no responsibility is assumed for clerical,
typographical, or proofreading errors, or omissions.
2011.9
In the interest of product improvement, specifications are subject to change without notice.
OMRON Corporation
Industrial Automation Company
http://www.ia.omron.com/
(c)Copyright OMRON Corporation 2011 All Right Reserved.
