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2 PURPOSE AND CHARACTERISTICS
The Cobra4 Sensor-Unit Acceleration contains a sensing el-
ement with three capacitive acceleration sensors that are ar-
ranged perpendicular to each other. An acceleration that acts
upon the sensors leads to the bending of freely movable lam-
inas within the sensors and thereby causes a change in ca-
pacity. The capacity is converted to a voltage signal:
The Cobra4 Sensor-Unit Acceleration can be connected to
one of the following measured data recording instruments, as
appropriate for the type of application, and transfer the
measured data to it:
a Cobra4 Wireless/USB-Link (12601-10) for tethered or
wireless data transfer to a computer or a mobile device,
a handheld Cobra4 Mobile-Link 2 instrument (12620-10),
a Cobra4 Xpert-Connect (12625-01) for synchronous
data transfer in connection with a Cobra4 Xpert-Link
(12625-99).
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
The Cobra4 Sensor-Unit Force has no manual operating el-
ements. Operation of it is carried out via a handheld Cobra4
Mobile-Link 2 or, in the case that it is connected to a Cobra4
Wireless/USB-Link or a Cobra4 Xpert-Connect, via a com-
puter or mobile device. The connection between the Sensor-
Unit and any one of the three measured data recording in-
struments is active as soon as it is made.
3.2 Functional elements
The sensors are inside the housing with their axes perpen-
dicular to each other. The sensors are built-in in such a way
that their axes run parallel to the edges of the housing. The
three axes are pictured on the top side of the unit as a Carte-
sian coordinate cross (Fig. 2).
Fig. 2: Cobra4 Sensor-Unit Acceleration, the directions of
the axes displayed
4 NOTES ON OPERATION
This Cobra4 Sensor-Unit Acceleration fulfils all of the tech-
nical requirements that are compiled in current EC guidelines
in connection with Cobra4 Wireless/USB-Link, Cobra4 Mo-
bile-Link 2 and Cobra4 Xpert-Connect. 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 rec-
ord data. To avoid failure or improper operation, please read
carefully through this section.
5.1 Putting Cobra4 Sensor-Unit Acceleration to use
Please make sure that the current version of measure is in-
stalled when collecting data with a PC. Download free of
charge via:
www.phywe.com … Downloads … Software download
Update measure-Software
Cobra4
Alternatively, the software update can be performed with the
measure DVD.
Connect the Cobra4 Sensor-Unit Acceleration to the meas-
ured data recording instrument selected from the three pos-
sible ones by means of the click-catch 15-pin plug connector.
The Sensor-Unit is then ready for use after a brief starting
phase (self-calibration), as the voltage for it is supplied by the
measured data recording instrument.
Further information on the control of measured data record-
ing instruments is to be found in their operating instructions.
5.2 Recording of acceleration data
Acceleration is measured along the three sensors in the unit
of the acceleration due to gravity gor in m/s2. The unit can be
selected on the PC, the mobile device or the hand-held
measuring instrument.
With the help of the Sensor-Unit Acceleration, acceleration is
measured in the reference system of the sensor. This is to be
taken into consideration in the interpretation of the data.
More detailed information on the recording of measured val-
ues and other functions is given in the operating instructions
for the measured data recording instruments.
