 SPECIAL SYSTEMS
>>
DOUBLE SHEET DETECTION
............................................................................................................................................................................................ |
|
►
Double sheet detection system |
|
 |
The Principle
is that an ultra high frequency ultrasonic transmitter fires a
sonic beam at the underside of the sheet. The beam causes the sheet to
vibrate, which in turn generates a very small sound wave on the other
side of the sheet.
This is then evaluated by the ultrasonic receiver. If there are two
sheets (a double feed), the signal is weakened to such an extent that
it instantly detects it. |
|
Ultrasonic sensors have set new standards in
automation |
|
 |
Ultrasonic sensors emit short, high-frequency sound pulses at
regular intervals. These propagate in the air at the velocity
of sound. If they strike an object, then they are reflected
back as echo signals to the sensor, which itself computes the
distance to the target based on the time-span between emitting
the signal and receiving the echo. As the distance to an
object is determined by measuring the time of flight and not
by the intensity of the sound, ultrasonic sensors are
excellent in double detection applications.
¡¡ |
Specifications.
|
Model name |
Dbk-4/CD/o/M18 E+S |
|
Transmitter-receiver spacing |
40mm ¡¾ 3mm |
|
Transmitter-receiver blind zone |
7mm in front of both transmitter and receiver |
|
Permissible angular deviation |
¡¾45¡Æ from the perpendicular to the sheet |
|
Working range |
Papers with grammages of 20-1200 g/m |
|
Residual ripple |
¡¾10% |
|
Response time, Trigger mode |
4.5 ms |
|
Response time, Free run mode |
24.5 ms |
|
Tripping delay, Trigger mode |
40 ms or state frozen until next enable |
|
Tripping delay, Free run mode |
160 ms |
|
Housing |
Nickel-plated brass sleeve |
|
Operating temperature |
+5¡ÆC to +60¡ÆC |
|
Weight |
270g |
|
|
|
 |
