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2 PURPOSE AND CHARACTERISTICS
The Cobra4 Sensor-Unit Motion measures with the help of
ultrasound signals the distance, velocity and acceleration of
an object.
According to the type of application, Cobra4 Sensor-Unit Mo-
tion can be connected to one of the following measured data
recording instruments and the current/voltage data be passed
to it.
•Cobra4 Wireless-Link (12601-00) for data transfer to a
computer by wireless,
•Cobra4 Junior-Link (12615-00) for student experiments,
data transfer via USB-cable,
•Cobra4 USB-Link (12610-00) for data transfer to a com-
puter via a USB-cable,
•handheld Cobra4 Mobile-Link instrument (12620-00).
The interface to measured data recording instruments is on
the front side of the Sensor-unit, whereby mechanically se-
cure engagement is ensured by a locking mushroom and a
hole.
3 FUNCTIONAL AND OPERATING ELEMENTS
3.1 Operating elements
Cobra4 Sensor-Unit Motion has no manual operating ele-
ments. Operation of it is carried out via a handheld Cobra4
Mobile-Link or, in the case that it is connected to a Cobra4
USB-Link or a Cobra4 Wireless-Link, via a computer. The
connection between the Sensor-Unit and any one of the three
measured data recording instruments is active as soon as it
is made.
3.2 Measurement inputs
On the front side of the Sensor-unit is located the opening to
send and receive the ultrasound signals.
4 NOTES ON OPERATION
This Cobra 4 Sensor-Unit Motion fulfils all of the technical
requirements that are compiled in current EC guidelines. The
characteristics of this product qualify it for the CE mark.
This instrument is only to be put into operation under special-
ist supervision in a controlled electromagnetic environment in
research, educational and training facilities (schools, universi-
ties, institutes and laboratories).
This means that in such an environment, no mobile phones
etc. are to be used in the immediate vicinity. The individual
connecting leads are each not to be longer than 2 m.
The instrument can be so influenced by electrostatic charges
and other electromagnetic phenomena (HF, bursts, indirect
lightning discharges) that it no longer works within the given
specifications. Carry out the following measures to reduce or
eliminate the effect of such disturbance: Ensure potential
equalization at the PC (especially with Laptops). Use screen-
ing. Do not operate high frequency emitters (e.g. radio
equipment or mobile radiotelephones) in the immediate vicini-
ty. When a total failure of the instrument occurs, unplug it and
plug it back in again for a reset.
5 HANDLING
This section describes how to use the Sensor-Unit and
record force data. To avoid failure or improper operation,
please read carefully through this section.
5.1 Putting Cobra4 Sensor-Unit Electricity to use
Please make sure that the current version of measure is in-
stalled on your PC.
Download free of charge via:
www.phywe.com … service … downloads … software …
measure
measure main program
measure module Cobra4
Alternatively, the software update can be performed with the
measure DVD.
Connect Cobra4 Sensor-Unit Electricity to one of the three
measured value recording instruments suitable for it via the
engaging 15-pin plug connector; The Sensor-unit is ready for
use after a brief starting phase (self-calibration), as the vol-
tage is supplied via the measured data recording instrument.
More detailed information on the control of the measured da-
ta recording instruments is given in their operating instruc-
tions.
Measuring principle
The sensor emits ultrasound signals that are reflected by the
object that is to be analysed. Based on this, the sensor then
calculates the distance between the sensor and the object
and, based on the change in distance, the velocity and acce-
leration. The unit for the transmission and reception of the
ultrasound signals is located at the front of the sensor.
Measurement
Ensure that the reflecting object is aligned absolutely parallel
with regard to the front of the sensor. In the measuring range
up to approximately 1 m, objects with a surface of 4 cm² can
be detected. The greater the distance is, the bigger the object
should be. Obstacles in the direct vicinity of the ultrasound
transmitter should be removed, if possible, in order to avoid
interference reflections.
6 TECHNICAL SPECIFICATIONS
(Typical for 25°C)
Operating temperature range 5... 40°C
Relative humidity < 80%
The Sensor-unit has 2 measurement modes:
Velocity
Acceleration
Maximum data rate
Resolution (distance)
0,25 ... 10 m
± 10 m/s
± 100 m/s²
10 Hz
5 mm
Velocity
Acceleration
Maximum data rate
Resolution (distance)
0,15 ... 2 m
± 10 m/s
± 100 m/s²
50 Hz
1 mm
