PHYWE Cobra4 User manual

1
www.phywe.de, © All rights reserved 12636-00 / 4616
Operating instructions
Cobra4 Drop Counter
12636-00
PHYWE Systeme GmbH & Co. KG
Robert-Bosch-Breite 10
D-37079 Göttingen
Telefon [phone]
Fax [phone]
E-mail [email protected]
Internet www.phywe.com
Fig. 1: 12636-00 Cobra4 Drop Counter
The unit complies with
the corresponding EU
guidelines.
TABLE OF CONTENTS
1SAFETY INSTRUCTIONS
2PURPOSE AND CHARACTERISTICS
3FUNCTIONAL AND OPERATING ELEMENTS
3.1 Operating elements
3.2 Functional elements
4OPERATING NOTES
5OPERATION
5.1 Start-up of the Cobra4 drop counter
5.2 Recording of measurement data
6 TECHNICAL DATA
7DISPOSAL
1 SAFETY INSTRUCTIONS
Read the operating instructions thoroughly and com-
pletely prior to starting the unit. This is important for your
own protection and for avoiding damage to the unit.
Use the unit solely for its intended purpose.
The unit is intended for use in dry rooms where there is
no risk of explosion.
Protect the Cobra4 drop counter against dust, humidity,
and vapours. Clean the unit with a slightly moist, lint-free
cloth. Do not use any aggressive cleaning agents or sol-
vents.
Ensure that no liquids penetrate the unit through its
openings, since otherwise the Cobra4 drop counter
would be damaged.
If you use the unit outdoors, ensure that no rain or splash
water penetrates the housing.
Use the experiment set-up solely for the intended pur-
pose.
Do not open the unit.
Connect the data output of the Cobra4 drop counter
solely to the intended measurement data recording de-
vices.
The optical path is composed of non-visible infrared ra-
diation. Do not look into the emitter (optical path).
Based on today’s state of software development, it is
impossible to guarantee that a product is absolutely free
from errors. This is why PHYWE Systeme GmbH & Co.
KG assumes no liability for damage resulting from the
installation or use of this unit.

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2 PURPOSE AND CHARACTERISTICS
The Cobra4 drop counter is used for counting the number of
drops dripping from a burette and, thereby, for the quantita-
tive determination of the volume of the dispensed liquid.
Depending on the type of application, the Cobra4 drop coun-
ter can be connected to the following measurement data re-
cording devices for transferring the measured values:
-to Cobra4 Wireless-Link (2) (12601-00 / -10) for wireless
transmission to a computer, smartphone or tablet,
-to Cobra4 USB-Link (2) (12610-00 / -10) for data trans-
mittance to a computer via a USB-cable,
-to the hand-held measuring instrument Cobra4 Mobile-
Link (2) (12620-00 / -10),
-Cobra4 Junior-Link (12615-00) for the data transfer to a
computer via a USB cable
3 FUNCTIONAL AND OPERATING ELEMENTS
3.1 Operating elements
The Cobra4 drop counter has no manual operating elements.
Its operation is controlled by the software via a Cobra4 USB-
Link, Cobra4 Junior-Link, or Cobra4 Wireless-Link as soon as
the connection between the sensor unit and one of these four
measurement data recording devices is set up.
3.2 Functional elements
The liquid drops are counted with the aid of a light barrier that
is located in the oblong hole in the middle of the housing. The
drop counter can be attached to support rods via its handle
and a bosshead. A red LED on top of the drop counter lights
up whenever the device has detected a drop.
4 OPERATING NOTES
In combination with the Cobra4 Wireless-Link, Cobra4 Junior-
Link, Cobra4 Mobile-Link and Cobra4 USB-Link, the Cobra4
drop counter fulfils the technical requirements that are sum-
marised in the current guidelines of the European Communi-
ty. The characteristics of the product entitle it to bear the CE
mark.
The unit must be used under the supervision of an expert and
in the electromagnetically controlled environment at research,
teaching, and training facilities (schools, universities, insti-
tutes, and laboratories).
This means that, in such an environment, radio transmission
devices, e.g. mobile phones, should not be used in the direct
vicinity of the unit. The connected cables must not be longer
than 2 m. Electrostatic charges or similar electromagnetic
phenomena (HF, bursts, indirect lightning discharge, etc.)
may affect the unit so that it will not work within the specified
data range.
The following measures reduce or eliminate potential inter-
ferences: avoid carpets; provide equipotential bonding; per-
form the experiments on a conductive, earthed surface; use
shields and shielded cables. Do not use radiofrequency
transmitters (radio sets, mobile phones) in the direct vicinity
of the unit.
5 OPERATION
This section describes the start-up of the sensor unit and the
recording of measurement data. Please read this section
carefully in order to avoid problems or malfunctions.
5.1 Start-up of the Cobra4 drop counter
Ensure that the current versions of the “measure” software
package and of the Cobra4 modules are installed.
Free software update at:
www.phywe.com
Service Downloads Software measure
“measure” main program
“measure” Cobra4 module
A free software update is also possible via the “measure”
DVD.
Connect the Cobra4 drop counter to one of the three possible
measurement data recording devices via the 15-pin connect-
or. The Cobra4 drop counter is immediately ready for use,
since its power supply is ensured via the measurement data
recording devices. More information concerning the control of
the measurement data recording process can be found in the
operating instructions of the measurement data recording de-
vices USB-Link, Junior-Link, Mobile-Link and Wireless-Link.
5.2 Recording of measurement data
Connect the drop counter to the transfer devices (see above).
Measurement principle:
The oblong hole in the middle of the drop counter includes an
infrared LED at one end. The radiation of this LED is detect-
ed by an infrared sensor that is located at the other end of
the oblong hole. Liquid drops that fall through the hole trigger
a signal in this light barrier arrangement. The drop counter
detects these signals and transfers them to the transfer de-
vice that is connected to the sensor unit for further pro-
cessing.
Measurement:
The drop counter is mounted above the titration vessel so
that the drops that are dispensed by the burette fall through
the oblong hole of the drop counter directly into the vessel.
The drop counter should be aligned as horizontally as possi-
ble in order to ensure that the drops fall through the oblong
hole without touching the side walls. Sensors for measuring
the changes of the solution to be titrated can be fastened in
the two holes on the right and left of the oblong hole with the
aid of knurled screws so that they dip into the solution.
The burette must be mounted so that its dropping tip is locat-
ed above the middle between the two side walls of the oblong
hole. The end of the dropping tip should be above the oblong
hole resulting in a certain distance between the dropping tip
and the light barrier so that the latter can count the drops in-
dividually.

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To ensure thorough mixing, the solution that is to be titrated
should be agitated with a magnetic stirrer or similar during
the measurement. In order to start the titration, open the bu-
rette slowly and gradually until it slowly dispenses drops. If
possible, only 1 drop per second should fall through the drop
counter into the solution, since otherwise the thorough mixing
of the solution cannot be guaranteed and the change in the
solution that is measured by the sensors would not be in line
with the added and measured volume of the added reagent.
A quantitative recording of a titration can be realised by dis-
pensing, for instance, 100 drops during a preliminary experi-
ment and by reading the dispensed volume off the burette.
Then, the number of drops and the read-off volume are used
to calculate the volume per drop. After the measurement, this
value can be used to convert the number of drops into a vol-
umetric value. To do so, convert the measuring channel that
has counted the number of drops in the “measure” main pro-
gram with the aid of the “Cannel modification” function into a
volume and then select this channel as the x-axis for the
measurement with the aid of the function “Cannel manager”.
6 TECHNICAL DATA
(typical values for 25°C)
Operating temperature range: 5... 40°C
Rel. humidity < 80%
Length: 200 mm
Width: 55 mm
Height: 20 mm
Length of the support rod: 90 mm
Diameter of the support rod: 10 mm
Diameter of the 2 electrode holders: 13 mm
Dimensions of the oblong hole: 25 mm x 15 mm
Length of the connecting cable: 90 cm
Maximum counting rate 5/s
Mass: 270 g
7 DISPOSAL
The packaging mainly consists of environmentally-friendly
materials that should be returned to local recycling stations.
Do not dispose of this product with normal
household waste. If this unit needs to be
disposed of, please return it to the address
that is stated below for proper disposal.
PHYWE Systeme GmbH & Co. KG
Customer Service
Robert-Bosch-Breite 10
D-37079 Göttingen
Germany
Tel. [phone]
Fax [phone]