OLS CASY TT Manual

CASY TT
CASY TT
CELL COUNTER & ANALYZER | Operators Guide
For life science research only. | Not for use in diagnostic procedures.

3
Table of Contents
Prologue 
I. Revision History.......................................................................................................................................5
II. Contact Addresses...................................................................................................................................5
III. Declaration of Conformity....................................................................................................................6
IV. Warranty .....................................................................................................................................................6
V. Trademarks ................................................................................................................................................6
VI. Intended Use.............................................................................................................................................6
VII. Conventions Used in this Operator’s Guide....................................................................................7
VIII. Handling Requirements.........................................................................................................................8
IX. Disposal of the Instrument ..................................................................................................................9
. Introduction 
. Functionality............................................................................................................................................10
. Measuring Principle..............................................................................................................................11
1.2.1 Digital Pulse Processing.........................................................................................................................11
1.2.2 Pulse Area Analysis.................................................................................................................................12
1.2.3 Measuring Range Dynamics.................................................................................................................13
.
Viability Determination using Electrical Current Exclusion.......................................................14
. Aggregation Correction .......................................................................................................................15
. CASY TT .....................................................................................................................................................15
. Device conguration 
. Measuring Unit.......................................................................................................................................18
. Measuring Capillary and External Electrode.................................................................................19
. Pressure System and Power Supply.................................................................................................20
. Control Panel...........................................................................................................................................20
3. Startup 22
. Choosing the Location .........................................................................................................................22
. Cabling ......................................................................................................................................................22
. Switch-On/-O.......................................................................................................................................23
. Preparing for Measurement...............................................................................................................24
. Maintenance and Care 
. Weekly Cleaning Routine ....................................................................................................................26
. Cleaning the Cylinders and the Sampling Chamber...................................................................27
. How to take the CASY Instrument Out of Operation.................................................................27

4CASY TT
Table of Contents
. Operation of CASY TT 
. General......................................................................................................................................................28
. Menu Control – MAIN MENU ............................................................................................................28
. MAIN MENU – Select Setup ...............................................................................................................29
. MAIN MENU – Edit Setup ...................................................................................................................30
. MAIN MENU – Select Capillary .........................................................................................................35
. MAIN MENU – Set Date and Time ...................................................................................................35
. MAIN MENU – System Settings........................................................................................................36
. MAIN MENU – Service Menu.............................................................................................................37
. Performing and Evaluating Measurements 
. Preparing Samples.................................................................................................................................38
. Measuring Samples and Displaying the Measuring Results....................................................39
. Numerical Measuring Results............................................................................................................40
. Points to be Observed when Performing Measurements ........................................................42
. Setting the Measuring Range and the Cursor Positions...........................................................46
.
Manual Cursor Control using Control Panel Keys.................................................................................. 48
. Outputting the Results.........................................................................................................................48
. Troubleshooting 
. Error Messages .......................................................................................................................................50
. Background too High............................................................................................................................51
7.3 Message “Concentration too high”.....................................................................................................52
. Message “Measuring Timeout! – Capillary is possibly blocked” ...........................................52
. Message “Large Air Bubble detected”............................................................................................53
. Error Message PR- or PR-................................................................................................................54
. Error Message PR-a, PR-b, PR-a, or PR-b ...............................................................................54
. Control Panel Display Dark or Light.................................................................................................55
. Calibration Defective or Lost .............................................................................................................55
. Error Message HW-a...........................................................................................................................55
. Poor Result Reproducibility................................................................................................................56
. Amount of Cells Higher than the Count in the Hemocytometer ...........................................57
. Data Output Using CASY excell.........................................................................................................58
7.13.1 Macros not Activated .............................................................................................................................58
7.13.2 Data is not Transferred...........................................................................................................................58
7.13.3
Using a Computer with a Multi-Core-Processor......................................................................................58
. Appendix 
. Data Output via the Serial Interface ...............................................................................................59
. Technical Data on CASY TT .................................................................................................................61

5
Prologue
PROLOGUE
I. Revision History
Version Revision Date
2.4 March 2010
2.5 May 2010
2.6 June 2015
© Copyright 2015, OLS OMNI Life Science GmbH & Co KG. All rights reserved.
Information in this document is subject to change without notice. No part of this document may be
reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose,
without the express written permission of OLS OMNI Life Science.
Questions or comments regarding the contents of this manual can be directed to the address below.
OLS OMNI Life Science GmbH & Co. KG
Karl-Ferdinand-Braun-Str. 2
28359 Bremen
Telefon: 0421 | 27 61 69-0
e-mail: [e-mail]
Online Support
CASY online support is available on www.cellcounting.de.
direct online contact
 manuals, literature & setup les
video manuals
tips & tricks
trouble-shooting
Every eort has been made to ensure that all the information contained in the CASY TT Operators
Guide is correct at the time of printing.
However, OLS OMNI Life Science GmbH & Co KG reserves the right to make any changes necessary
without notice as part of ongoing product development.
II. Contact Addresses
Manufacturer OLS OMNI Life Science GmbH & Co. KG
Karl-Ferdinand-Braun-Str. 2
28359 Bremen
Phone: +49-421 | 27 61 69-0
e-mail: [e-mail]
www.cellcounting.de
www.ols-bio.de
Distribution Please nd a list of international distribution
partners on www.cellcounting.de
Revision History

6CASY TT
III. Declaration of Conformity
The instrument meets the requirements laid down in Council Directive 2004/108/EC
relating to “Electromagnetic Compatibility” and Council Directive 2006/95/EC relating
to “Low Voltage Equipment”. The following standards were applied: IEC/EN 61326-1
(EMC) and IEC/EN 61010-1 (Safety).
IV. Warranty
The warranty conditions are specied in the sales contract. Contact your OLS representative for
further information. Any unauthorized modication of the instrument invalidates the guarantee
and service contract.
V. Trademarks
CASY is a trademarks of OMNI Life Science GmbH & Co KG.
Other brands or product names are trademarks of their respective holders.
VI. Intended Use
The CASY TT is intended for highly standardized cell counting and accurate measurement of cell vi-
ability, cell aggregation and cell volume. The technology of the CASY TT combines a proven particle
measurement technique, referred to as the electrical sensing zone technique (ISO 13319), with a
modern method of signal evaluation, pulse area analysis. The CASY TT is intended for life science
research and must be used exclusively by laboratory professionals who are trained in laboratory
techniques and have studied the instructions for use of this instrument. The CASY TT is not in-
tended for use in diagnostic procedures.
Declaration of Conformity

7
Prologue
VII. Conventions Used in this Operator’s Guide
Text Conventions
To impart information that is consistent and memorable, the following text conventions are used in
this Operator’s Guide:
Numbered Listing Describes the steps in a procedure that must be performed in the order
listed.
Italic type Important notes and information notes are shown in italic type.
Orange italic type Refers to a dierent section in this Operator’s Guide.
Symbols
In this Operator’s Guide symbols are used as a visual signal to highlight important points.
Symbol Heading Description
WARNING This symbol is used to indicate that noncompliance with
instructions or procedures could lead to physical injury or even
death or could cause damage to the instrument.
BIOHAZARD This symbol indicates that certain precautions must be taken
when working with potentially infectious sample material.
IMPORTANT NOTE Information critical to the success of the procedure or use of
the product.
INFORMATION NOTE Additional information about the current topic or procedure.
➞Table continued on next page.
End of table.
The following symbols appear on the instrument:
Symbol Heading Description
WEEE Electrical and electronic equipment marked with this symbol are
covered by the European Directive WEEE.
The symbol denotes that the equipment must not be disposed
o in the municipal waste system.
Conventions Used in this Operator’s Guide

8CASY TT
VIII. Handling Requirements
It is important to observe the following safety instructions and guidelines to ensure safe and reliable
operation of CASY TT:
Place the instrument on a solid, dry work table that is exposed to neither strong mechanical
vibrations nor high-volume noises (e.g., ultrasonic baths).
Choose the installation site so that CASY TT is protected from mechanical damage and water and
solvent spillage.
Choose a room that is as smoke- and dust-free as possible and that has a constant room
temperature of between +15°C and +32°C.
This instrument has been designed and tested to CISPR 11 Class A. In a domestic environment
it may cause radio interference, in which case, you may need to take measures to mitigate the
interference.
The electromagnetic environment should be evaluated prior to operation of the device.
Concerning immunity test requirements, the instrument has been designed and tested for
use in controlled electromagnetic environment.
 Do not operate this instrument in close proximity to sources of strong electromagnetic elds
(e.g., unshielded intentional RF sources such as mobile telephones), as these may interfere
with the proper operation.
For further protection an Uninterruptible Power Supplies (UPS) is recommended, depending
upon the quality of electrical grounding of the local electrical power supply.
Use the protection shield for every measurement!
Only trained personnel in a controlled laboratory environment should operate the CASY Instru-
ment.
All services and repairs should be performed by authorized service technicians only.
 Always ensure that there is sucient CASY ton in the CASY ton storage container.
Clean the containers before reusing them.
Always observe the safety regulations when handling CASY ton and CASY clean.
Waste contaminated with tissue or cells, e.g., waste container, CASY cups, pipette tips, etc., must
be disposed of according to the recommended rules for handling biohazardous materials.
Any leaks in the liquid management system must be repaired immediately. Contact your
distributor or authorized service technician.
 When the CASY TT uid system contains CASY ton, always ensure that it does not dry out, to
prevent malfunction or damage to the uid system and valves caused by salt crystals.
Always wear protective clothing, particularly gloves, when handling samples with any risk of
biohazard.
Dirt or dust particles should not gain access into the device.
Ensure that all equipment required for sample preparation, e.g., CASY cups, pipette tips, etc.,
are stored in a dust-free environment and are free of any grease or oil. Even minor amounts of
grease or oil my cause high background readings especially with the 60 μm and the 45 μm capil-
lary!
For your own safety, please consider all biological material as potentially infectious. Handling and
disposal of such material should be performed according to local
safety guidelines. Spills
should be immediately disinfected with an appropriate disinfectant solution to avoid
spread-
ing infection to, and contamination of, laboratory personnel or equipment. When working with
potentially infectious material, always use protective gloves (powder-free).
 Please see chapter Maintenance and Care for instructions on cleaning the CASY TT.
Warnings and Precautions

9
Prologue
General Precautions
Make sure that the main switch can be reached easily. Inappropriate location of the instru-
ment can cause incorrect results and damage to the equipment parts.
Keep all potentially inammable or explosive material (e.g., anesthetic gas) away from the
instrument. Spraying liquid on electrical parts can cause a short circuit and result in re.
During reghting operations, disconnect the power line of the CASY TT.
Electrical Safety
The CASY TT is designed in accordance with Protection Class I (IEC). The chassis/housing
of the instrument is grounded to protection earth (PE) by means of a cord. For protection
against electrical shock hazards, the instrument must be directly connected to an approved
power source such as a three-wire grounded receptacle for the 110 V or 230 V line. Do not
use an ungrounded receptacle; have a qualied electrician replace the ungrounded recepta-
cle with a properly (PE) grounded receptacle in accordance with the local electrical code. Do
not use an extension cord. Any break in the electrical ground path, whether inside or outside
the instrument, could be hazardous.
Under no circumstances should the user attempt to modify or deliberately defeat the safety
features of this instrument. If the power cord becomes cracked, frayed, broken, or otherwise
damaged, replace it immediately with the equivalent part from OLS.
IX. Disposal of the Instrument
All electrical and electronic products should be disposed of separately from the municipal waste
system. Proper disposal of your old appliance prevents potential negative consequences for the
environment and human health.
The instrument must be treated as biologically contaminated hazardous waste. Final disposal
must not endanger waste handlers. As a rule, such equipment must be sterile before it is
passed on for nal disposal. For more information contact your local OLS Support person-
nel. The instrument should also be decontaminated prior to shipping it for outside service or
repairs.
Components of your CASY TT which are marked with the crossed-out wheeled bin symbol are
covered by the European Directive 2002/96/EC (WEEE).
These items must be disposed of via designated collection facilities appointed by government
or local authorities. For more information about disposal of your old product, please contact
your city oce, waste disposal service or your local OLS Support personnel.
It is left to the discretion of the responsible laboratory organization to determine whether the CASY
TT Instrument and the Control Panel are contaminated or not. If contaminated, treat the Control
Panel in the same way as described for the cylinders and the sample chamber (see chapter Main-
tenance and Care).
Warnings and Precautions

10 CASY TT Operator‘s Guide
. INTRODUCTION
The CASY System is a development based on extensive experience gained in analytical working
methods in the elds of cytobiology, microbiology, biochemistry, and physics. Its ergonomic and
easy operation were developed specically for day-to-day, routine use. Standardized cell counting
methods and accurate measurement of cell viability, cell aggregation, and cell volume with high
measuring range dynamics make the CASY Cell Counter and Analyzer an indispensable tool for the
qualitative and quantitative assessment of cell cultures.
. Functionality
The features of the CASY Cell Counter and Analyzer are cell counting and cell analyzing. The
analyzing function additionally determines parameters which are important for the quality control
of cell cultures. These include:
High-resolution size distribution
The size distribution of a cell culture is a typical characteristic and serves as a ngerprint of the
status of the cells.
Cell volume
The cell volume is precisely measured by the CASY Cell Counter and Analyzer. Based on the cell
volume, the corresponding cell diameter is calculated.
Aggregation correction
Determination of the mean degree of cell aggregation. The aggregation factor is used to calculate
the total number of single cells, including cells in cell clusters (aggregation correction).
Viability determination
Viability of mammalian cell lines and primary cells, when analyzed in monoculture, is measured
by a non-invasive method, the electrical current exclusion method. However, there can be situa-
tions where viability determination using electrical current exclusion is not possible (see section
Viability Determination using Electrical Current Exclusion).
Debris
Small debris particles originating from cell destruction or extracellular matrix (cell debris) can be
recognized and quantied beside the cell populations by the CASY Cell Counter and Analyzer.
The contamination by cell debris is used as an additional parameter for the quality control of the
cell culture.
The calibration of the CASY Cell Counter and Analyzer is factory certied and non-changeable by the
user, oering a very high level of standardization. This guarantees that the results can be compared
from user-to-user, from lab-to-lab, from day to day and from instrument-to-instrument.
Functionality

11
Introduction
. Measuring Principle
The technology of CASY Systems combines a proven particle measurement technique, referred to
as the
“Electrical Sensing Zone” technique (ISO 13319), with a modern method of signal evaluation, the
“Pulse Area Analysis”.
.. Digital Pulse Processing
Pulse Area Analysis was developed in 1987 on the basis of Digital Pulse Processing (DPP), a tech-
nique developed for the digital recording of electrical signals more than 40 years ago. For cell
analysis, DPP is combined with a high scanning rate and a highly-standardized method of analyzing
cell signals. This combination facilitates unprecedented measuring range dynamics and guarantees
maximum resolution and excellent reproducibility for all measuring parameters.
Lift tube
Start
400 µl
200 µl
Measuring
pore
Electrodes
Measuring
capillary
Electrolyte solution (CASY ton)
with cells in suspension
Figure 1: Measurement principle of the CASY Cell Counter and Analyzer.
As shown in Figure 1, cells are suspended in CASY ton, an electrolyte developed specically for cell
counting. For the measurement, the cells are aspirated through a precision measuring pore of de-
ned geometry at a constant ow speed.
Signal Generation
The precision measuring pore is designed as a hole within an articial precious stone, which is
cast inside the capillary body. The electrolyte-lled measuring pore represents a dened electrical
resistance (constant current). During their passage through the measuring pore, the cells displace
electrolyte and thereby generate electrical pulses. Each generated electrical pulse is recorded as a
cell count and the size of each pulse is equivalent to the cell volume because every cell displaces
exactly the quantity of electrolyte corresponding to its cell volume. The changes in voltage when a
cell or particle is passing the pore are sampled with a frequency of 1 MHz.
Measuring Volume
For calculation of the cell concentration it is essential to know the exact volume of the cell suspension
passing the measuring pore. This volume (measuring volume) can be dened by the user and is pre-
cisely determined by the CASY System using a lift tube, which is calibrated in volume.
Measuring Principle
Digital Pulse Processing

12 CASY TT Operator‘s Guide
.. Pulse Area Analysis
The measuring signal, for example the electrical pulse generated by a cell when passing the
measuring pore, is scanned by the CASY Cell Counter and Analyzer at high frequency (1 MHz). As
well as the amplitude of the measuring signal, it also records the shape and time course of the signal
as a whole (Figure 2).
The CASY Cell Counter and Analyzer calculates the integral of the measuring signal from the individ-
ual readings. The calculated signal areas are evaluated by a standardized method and accumulated
in a multi-channel analyzer. From the original volume-linear size distribution with a resolution of
524,288 measuring channels nally a diameter-linear size distribution with a resolution of 400
display channels is calculated.
Electrodes
Measuring pore 1 million measures/sec.
Assigned in 512.00 channels
⇒ Signal analysis in area,
height, width and course
of time
Signal Analysis
Figure 2: Pulse Area Analysis.
Measuring Principle
Pulse Area Analysis

13
Introduction
.. Measuring Range Dynamics
The signal amplier technology, developed specically for the CASY Cell Counter and Analyzers,
guarantees excellent measuring range dynamics (>1:70,000 in terms of volume and >1:40 in terms
of diameter respectively).
Measuring range dynamics is described as the ratio of the smallest to the largest particles that can
be analyzed simultaneously. This guarantees that the entire physical measuring range of the mea-
suring capillaries used, from approximately 2% to approximately 80% of the measuring pore diam-
eter, is always in view. As an example, the entire physical measuring range of the 150 μm capillary
ranges from 3.2 μm (2% of 150 μm) to 120 μm (80% of 150 μm).
Due to the huge dynamic measuring range with 1:40, in terms of the diameter oered by the
CASY Cell Counter and Analyzer, objects with a size of 3.2 μm and approximately 40-times
bigger objects, for example, objects with a size of 120 μm, can be measured in one measurement
using the 150 µm capillary. When analyzing cell cultures, this means that you can analyze everything
from very small debris particles up to very large cell aggregates simultaneously. Figure 3 below shows
a typical size distribution of an animal cell line generated by the CASY Cell Counter and Analyzer.
Based on the precisely determined cell volumes, the CASY Cell Counter and Analyzer calculates the
corresponding cell diameters, which are displayed together with their associated absolute counts,
resulting in the typical high-resolution size distribution:
Figure 3: Typical CASY Cell Counter and Analyzer size distribution on an animal cell line
Capillary Sizes
In order to cover dierent size ranges for specic applications, capillaries with dierent pore sizes
are available covering dierent measuring ranges. In addition to the 150 μm capillary, the 45 μm
capillary (pore size 45 μm) and the 60 μm capillary (pore size 60 μm) are oered.
A CASY TT can be equipped with either the 150 μm capillary only or with all three capillaries (150
μm, 60 μm and 45 μm). The 45 μm capillary detects objects starting from 0.7 μm and therefore is
used, for example, to analyze bacteria or small fungi, whereas the 60 μm capillary detects objects
starting from 1.2 μm and is used, for example, for analyzing yeast cells, platelets, sperms, algae,
plankton, etc.
Based on the measurement principle and dierent available capillary sizes, a broad range of objects
can be quantied by the CASY Cell Counter and Analyzer, as for example, all types of mammalian
cells (cell lines and primary cultures), blood cells, algae cells, yeast cells, bacteria, sperm, pollen,
worm eggs, particles, etc.
Measuring Principle
Measuring Range Dynamics

14 CASY TT Operator‘s Guide
. Viability Determination using Electrical Current Exclusion
The CASY Systems use a label-free, non-invasive method, called the Electrical Current Exclusion
method, for measuring cell viability of mammalian cell lines. Viability determination may also be
possible with, for example, algae.
Like with well known dye-based assays this viability determination depends on the membrane
integrity of the cells. Since intact cells have intact cell membranes, they can generally be considered
as electrical isolators and an increased level of resistance is achieved over the measuring pore.
This increase in resistance is a dimension for the volume of the cells. They are measured with their
true cell volume. In contrast, dead cells whose membranes no longer act as an electrical barrier are
recorded mainly by the size of their cell nucleus (see Figure 4). In order to guarantee the ability for
viability determination, it is important that the cells pass through the pore individually.
Figure 4: Viability determination of an animal cell line using the electrical current exclusion method.
Normalization and Evaluation Cursors
Since the volume of the cell nucleus is signicantly smaller than the volume of the entire cell, the
populations “debris”, “dead cells”, and “viable cells” can be clearly distinguished in the high-resolu-
tion size distribution. For calculating the viability in the analyzed suspension, two pairs of cursors
are available to dene specic size ranges and to calculate the percentage of viable cells.
 The counts in the size range of the normalization cursors dene the total cell number and are
normalized to represent 100%.
 The counts in the evaluation cursor range dene a part of the total cell number used to calculate
a percentage.
Therefore, viability is calculated by setting the normalization cursor range such that it includes the
dead and viable population, whereas the evaluation cursor range includes the viable population
only. Based on these settings the, CASY Cell Counter and Analyzer calculates the viability in %.
If objects with the same volume as dead cells are additionally present in the suspension to be ana-
lyzed, they are recorded in the size range of dead cells as well, and therefore viability determination
is not possible. The reason is that these objects would further increase the number of total cells,
which would incorrectly lower the viability.
For more information on using the normalization and evaluation cursors, see section
Setting the Measuring Range and the Cursor Positions and as well as videos and guides on www.cell-
counting.de.
Viability Determination using Electrical Current Exclusion

15
Introduction
Aggregation Correction
The CASY Cell Counter and Analyzer oers a method to analyze even clumpy cell suspensions with
its integrated aggregation correction. By analyzing the size distribution, the CASY Cell Counter and
Analyzer determines the statistically most occurring cell size, the volume of the statistically “repre-
sentative single cell”. The typical single cell volume is displayed in the analysis protocol as the peak
volume. The total volume of all measured events in the size range of single cells plus aggregates is
divided by the volume of the representative single cell to calculate the total number of single cells.
Cell aggregates thereby are classied into their single cells, thus making it possible to determine
the single cell count including the number of single cells in aggregates. The CASY Cell Counter and
Analyzer represents this correction in the form of an aggregation factor. The mean aggregation fac-
tor is used to record the aggregation correction. This parameter also can be used as a further quality
control parameter for the characterization of cell cultures.
For more information on using aggregation correction and determining the aggregation factor,
please visit www.cellcounting.de.
. CASY TT
The CASY TT combines a high degree of ergonomics with functionality. At the push of a button, the
electronics:
 Control the measuring stand
 Record the measuring data
 Evaluate the measuring data via a multi-channel analyzer
 Calculate and display the measuring results on the CASY Control Panel
All measuring parameters can be set up with a minimum of steps. For each measuring capillary, up
to 20 settings can be permanently stored for various cell types or various applications and remain
available the next time the device is switched on.
To output the data, a printer (at least PCL 3) can be directly connected to the device. For more
convenient display, storage and further evaluations, the measurement data can also be exported to
Microsoft Excel through a fully automated process using the CASY excell Software which is delivered
together with each system. For more information on CASY excell see the installation instruction for
CASY excell or visit www.cellcounting.de.
Aggregation Correction

16 CASY TT Operator‘s Guide
. DEVICE CONFIGURATION
CASY TT comprises the following functional units:
Measuring stand consisting of measuring unit, pressure systems and main power supply (see
Figure 5).
Measuring capillaries (see Figure 5); the 150 µm capillary is installed on delivery, depending
on your CASY TT version the 60 µm and 45 µm capillaries are delivered in their storage cups
included in the accessory box.
Protection shield (delivered with cable in the accessory box)
Control panel with graphic display and 13 control keys (see Figure 6).
Measuring unit, pressure system and mains power supply are housed in three separate metal
cylinders, guaranteeing maximum protection for the highly-sensitive measuring electronics, and
shielding against interference. The additional use of a protection shield, positioned around the cap-
illary during the measurements completely avoids external interference.
Consumables such as CASY ton, CASY clean, CASY cup, CASY blue, as well as accessories such as the
CASY rack and dispenser can be ordered separately.

17
Device conguration
Calibrated Vertical Tube
Pressure System
(concealed)
Light-Emitting Diodes
Measuring Unit
External electrode
Protection Shield
Cable (connecting
Protection Shield and
the Measuring Unit)
Storage Container
Sample platform
Precision Measuring Capillary
Waste Container
Base
Power Supply
Data Socket (DB9)
Parallel port (DB25)
Serial port,
RS232 (DB9)
Power Switch
Power input
socket
Voltage selector
Frontal view:
Rear view:
Figure 5: Schematic of CASY TT, frontal and rear view

18 CASY TT Operator‘s Guide
. Measuring Unit
The measuring unit (see Figure 5) contains the measuring electronics, the uid system and the
valves required to control the measuring process. The close monitoring of the measuring volume
(200 or 400 µl) required to determine the concentration is carried out by a light-barrier monitored,
calibrated precision vertical tube. The CASY System handles larger measuring volumes (maximum
4 ml), employing a multiple measurement system. The results of the individual measurements are
accumulated. The CASY System operates almost dead-volume free, i.e., the required sample quan-
tity is only slightly larger than the measuring volume. The control and monitoring of the measuring
process are designed to exhibit maximum protection against interference. Any faults that do occur
are automatically detected by the CASY System and the user is notied.
The sampling chamber accommodates the following elements:
Measuring capillary
External electrode
Sample platform
Waste container (left)
Storage container (right)
The measuring unit is controlled by the control panel (see Chapter 2.4 and Figure 6). An inspection
window, which also enables the vertical tube to be monitored visually, is situated above the sam-
pling chamber. The inspection window accommodates three light-emitting diodes, which indicate
the lling level of the vertical tube. The green light-emitting diode indicates the start of a measure-
ment, the lower red light-emitting diode indicates when the 200 µl level is reached and the upper
red light-emitting diode indicates when the 400 µl level has been reached.
Before the start of each measurement, the contents of the measuring capillary are emptied into
the waste container. The sample volume is then aspirated through the measuring capillary under
constant low pressure. The progress of the meniscus can be tracked in the inspection window. The
time required to reach the light barriers depends on the diameter of the used measuring capillary
and is precisely monitored by the CASY System. This process enables potential faults resulting from
measuring capillary blockages to be automatically detected. During the measurement process, the
vertical tube is also monitored for disturbances caused by air bubbles.
Blockages are removed by running a clean cycle, which, in addition to relling the internal uid sys-
tem, actively counter-ushes the measuring pore (see Chapter 6.4). The required CASY ton is sucked
in from the storage container and then emptied into the waste container. The entire volume of the
internal uid system is approx. 2 ml.
Measuring Unit

19
Device conguration
. Measuring Capillary and External Electrode
The external electrode (see Figure 5) is made of platinum, arranged before the measuring capillary,
so that it rotate freely and be pulled downwards when necessary.
The measuring capillary (see Figure 5) is made of highly resistant plastic. It is secured to the
sampling chamber cover by a cap nut. At the lower end of the capillary body, an articial precious
stone is cast with the precision measuring pore. The measuring pore has a cylindrical geometry with
a diameter to length ratio of 1:1. The axial arrangement of the hole minimizes the risk of blockage
and prevents impurities from accumulating inside the capillary body.
To change the measuring capillary, rst carefully rotate the external electrode forwards. Then re-
lease the cap nut and remove it with the measuring capillary by pulling downwards. To prevent the
measuring capillary becoming contaminated with grease and dust, avoid touching its lower end,
which is immersed in the sample.
To re-assemble, screw in the cap nut manually and do not use a tool! Ensure that the tube extending
inside the measuring capillary is not buckled or pinched during assembly. Carefully rotate the exter-
nal electrode, without bending, and return it to its original position. Ensure that the background is
monitored before commencing the measurement (see Chapter 3.4).
If you nd it necessary to change the measuring capillaries several times in one day, store the un-
used ones in particle-free CASY ton.
Unused measuring capillaries must always be cleaned thoroughly before being stored. Dried resi-
dues in the measuring pore can result in subsequent blockages. This can be prevented by placing
the measuring capillaries in CASY clean and leaving overnight. The following day, ush the mea-
suring capillaries carefully using CASY clean and then ush repeatedly with distilled water. Blow
the uid from the measuring capillaries and store in a clean place.
The measuring capillaries should be cleaned using only the CASY clean agent specied by OLS
OMNI Life Science. Other agents may destroy the measuring capillaries. OLS OMNI Life Sci-
ence is not liable for any damage caused by using alternative cleaning agents.
Measuring Capillary and External Electrode

20 CASY TT Operator‘s Guide
. Pressure System and Power Supply
The pressure system is accommodated in its own cylinder situated behind the measuring unit (not
visible in Figure 5). A no-maintenance vacuum pump, combined with the latest pressure sensors,
guarantees that the vacuum required to aspirate the sample remains constant, irrespective of exter-
nal pressure. The pressure system also interacts with the valves on the measuring unit to control all
uid movements required to empty the vertical tube, replenish the uid system and counter-ush
the measuring capillary.
The power supply for the measuring electronics of the CASY System is housed in the cylinder
arranged outside to the right (see Figure 5). Special lters ensure that the mains power supply is
aorded maximum interference protection.
. Control Panel
The control panel (see Figure 6) consists of a graphic display and a membrane keyboard exhibiting
13 keys. In measuring mode, the graphic display shows the size distribution and indicates the mea-
suring results. All measuring and output parameters can be displayed and adjusted through the
menu control.
The keyboard is divided into three functional areas. The top right-hand area accommodates the keys
used to enter the measuring and output parameters. The bottom right-hand area accommodates
the keys used to control the measuring unit and output the results to the printer. On the left are the
keys used to position the evaluation and the normalization cursors. All keys have a clearly dened
pressure point.
Pressure System and Power Supply