Selection of ultrasonic sensors, instruments and systems for industrial applications
Selection of ultrasonic sensors, instruments and systems for industrial applications
OP - US 1
Airborne
sound based distance meter.
Precision distance measurements, contact-free, in industrial environment. Thickness measurements using reference points. Operation principle: The distance is measured by the time-of-flight of airborne ultrasound pulses (frequency 100 kHz). Transmitter and receiver is the external sensor OP-US 1. The thickness is determined by the difference between the reference value (distance to the object´s support) and the measured value (distance to the object surface). The repetition rate is 50 Hz.
Highlights:
- contact-free from front face
- high precision (1/10 mm or better)
- suitable for process control
- filters, noise suppression
- easy set up and easy control, PC based
more information:- sensor -interface -algorithms -software -accessories
Sensor OP-US S1
- used for thickness
and distance measurements
- internal reference reflector
- measuring range starts from front face
Accessories
Sometimes measuring tasks can only be solved using specific additional means.
Mostly these are software changes, but sometimes mechanical accessories are
needed. In the following some accessories are listet and described. The following
describes some accessories:
The focussing paraboloid OP-US FS can be mounted directly on the sensor. The
measuring spot has a diameter of approximatly 2 mm, but its range is limited
by only a few mm. The applications for focused sensors are the measurement of
small objects such as wires, ropes or strongly curved or declined surfaces.
With the deviation mirror the ultrasound beam can be deflected to the opposite
direction. (for transmission and reception). Due to this, the sensor can be
turned down, while measuring in the upward direction. With this device the sensor
is protected from larger particles, which could fall down and damage the sensor.
. The deviation mirror is directly mounted on the sensor.
Precision measurements need a controlled medium between the sensor and the object
to be measured. The best way to manage this is to superimpose a strong and constant
airflow at right angles to the measuring ultrasound beam. Small variations and
striae in the air are thus suppressed. This is important if hot surfaces are
present.
Interface Display: Number of digits .......................................5
Analog out: Current interface ..........................4..20 mA (resolution 12 bit)
Optional: voltage interface ............... 0 ..5 V
Switch contact: Relay .............................................. max. 1A
Digital interface: Seriel RS-232 ............................ 9 pin Sub D (4800 baud)
Control inputs: programmable push button and up/down switch.
optional:external synchronisation (1 LS/TTL).
-back
Evaluation algorithms in data processing:
- adjustable gates to exclude reflectors
- automatic tolerance bands for noise suppression
- filtering, averaging
- automatic gain control
Algorithms for stabilization:
- internal temperature compensation
- object slope compensation (pat.pend.)
- automatic reference measurements are taken, if the object has left the measuring area.
- Timing control to exclude entrance and exit effects in periodic measurements.
Software
The measured results are available at the RS232 interface and can be processed by different sofware programs. A special windows program is availabel, which can be controled in seperate windows and which transfers the values on-line in the first column of an EXEL worksheet.
Application
Field: Precision thickness measurements, contact-free, in industrial
environment. Process control and quality control.
Operation principle: The thickness is measured by the time-of-flight of airborne ultrasound pulses (frequency 100 kHz) to both sides of the test object. Transmitter and receiver is the external sensor OP-US 1. The thickness is determined by the difference between the fixed distance of the two sensors and the sum of the two distance measurements.
Highlights:
- contact-free from front face
- high precision (1/10 mm or better)
- suitable for process control
- filters, noise suppression
- easy set up and easy control, PC based
more information:-
sensor -interface -algorithms
-software -accessories
-back
Standard shapes
The achievable accuracy of thickness measurements with airborn ultrasound depends
on the length of the free air gap between the sensors and the object to be measured.
A larger gap gives more space for the measured object and more place for the
operator, but decreases the accuracy. Three standard shapes are available, each
of them left- or right handed (type L or R, type L in the picture). A larger
width can be customized with aluminium profiles. Deviation mirrors and fans
can be mounted.
OP-US 2 for continuous production processes:
Especially designed for continously produced products, where no reference measurements can be done, an automatic zero measuring scanner is available. Periodically the thickness meter is removed from the product line and a reference measurement is made. The software updates the internal value automatically for the distance of the sensors. The achievable accuracy (depending of course on the individual problems) is about +/- 0,01 mm. By averaging higher accuracies up to 0.001mm are feasable. The exact shape should be matched to the measuring task. For measuring ranges up to 3 mm, the distance of the sensors should be about 20 mm, to give a high accuracy. The standard range for scanning, that is the maximum distance of the measuring point from the border of the product, is 320 mm. The instrument is oprated with 110/220 V A.c. It should be mounted on a stable and independent rack.
OP - US S2 / S3
The sensors OP-US S2 and the
microfone OP-US S3 differ in the electronic design, in the evaluation
algorithms and in the application.
Housing: aluminum cylinder 60 mm diameter, 48 mm length.
Fastening and electrical connection via a threaded bolt M24 x 1.5 and mains
lead cleat. Total length 84 mm. Two holes in the cover: operation of the potentiometer
and two color LED.
Electrical connection: 12..30V, DC, 50 mA. 3-wire cable. After power-on the LED displays red during the setup time.
Distance sensor OP-US S2
Application:The sensor is an ultrasonic distance meter which can be used to control a niveau within two limits or related application. By selection of a small hysteresis the sensor can be used to switch at a threshold distance.
Operation: The only parameter which can be controled locally by screw
driver adjustment is the switching distance. Internal parameters as averaging,
noise supression, limits, gates, hystereses are factory programed.
The LED is green, if the switch is on and the sensor detects an echo in the
acceptance range. If the distance is larger than the adjusted threshold, the
switch turns off and the LED turns red. This remains up to the case, that the
distance becomes smaller than the acceptance range.
Options: analog out, laser pointer, external trigger input.
Airborn sound microfone OP-US S3
Application: The sensor OP-US S3 is used to monitor the integrity of
high pressure systems or related applications by evaluation of the frequency
content of the environmental noise. The sensor scans the frequency content of
the airborne sound and activates the alarm output if repeatly ultrasonic waves
are detected. A leakage in a high pressure system is an excelent source for
airborne sound.
Operation: The only parameter which can be controled locally by screw
driver adjustment is the noise level. Internal parameters as averaging, noise
supression, limits, gates, hystereses are factory programed.
The LED is green, if the switch is on and the sensor detects an echo in the
acceptance range. If the sound amplitude is larger than the adjusted threshold,
the switch turns off and the LED turns red. This remains up to the case, that
the noise level becomes smaller than the acceptance range.
Option : Front side LEDs.
Accessories: Test transmitter with variable output to check the sensor
performance.
O
Application:
The US-TESTER is made for tribological investigations and characterization of surface and surface layer under the influence of ultrasonic vibrations.
The test setup constists of a controllable oscillator (amplitude, frequency
and duration) and an adapted amplifier. The parameters are controlled by the
internal computer or by an external PC.
This instruments operates the ultrasonic probe, which can be attached to the
test specimen with various interfaces and various loads.
The impact on the surface ist evaluated by a microscope.
Options: different resonance frequencies
of the probe or different vibration directions of the tip.
Examples of systems in poduction and quality control.
Quality control in wood production. The task is to measure the thickness and the curvature of the plates along two tracks on the wood plate passing the measuring frame.
3-dimensional scanner
Scanner for plastic foils. The thickness distribution over the area of the plastic sheet is automatically measured and displayed. The forward feed of the foil is syncronized with the transverse scan. The handling is similar to a copy machine.
4-dimensional scanner
Shape determination of rotationally symmetrical steel objects. Determination of diameters, ovalities. height of connection lines. The object is scanned with a focused sensor.
Axes: - turntable - x-axes of the scanner - y-axes - angle of sensor versus the surface
