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ActiveTwo User Manual Version:2.4 Date: BioSemi WG-Plein 129 1054SC Amsterdam Voice : +31 20 330 2957/2958 Fax : +31 20 330 2959 ABN-AMRO : 52.29.81.143 KvK Amsterdam : 33.267.855 VAT number : NL.8079.41.116.B.01 |
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Part 1: Hardware
Index: 1. General
1.1 About
this manual
1.2
Markings on components
1.3
Certification
1.4
Intended purpose
1.5
System layout
1.6 Safe
use
1.7
Specifications
2. System components
2.1
Active Electrodes
2.2
AD-box
2.3
Battery-box
2.4
Charger
2.5
Receiver
3. Maintenance
3.1
General maintenance
3.2 Electrodes
handling
1.1 About this Manual |
This manual describes the
use and maintenance of the BioSemi ActiveTwo biopotential measurement system.
Read this manual completely before putting the system into service. The
following icons are used in this manual:
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Safety
warning Failure
to follow these instructions may cause harm to subjects or operators. |
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Important note Failure
to follow these instructions may lead to unexpected operation or defects of
the system. |
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Background information This
information does not immediately concern the basic use of the system, but is
useful for understanding the designs philosophy and scientific opportunities
offered by the system. |
Additional information is
available on the BioSemi website at www.biosemi.com.
In many places inside this manual, there are links to additional comments on
our website. The extra comments on our website are regularly updated according
to user feedback, and may therefore cover extra information and user
suggestions not yet available at the time of creating this manual.
For questions, please contact
BioSemi at: Tel: +31 20 3302956
Fax: +31 20
3302959
Email: info@biosemi.com
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1.2 Markings on components |
The following icons are
used on ActiveTwo components:
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Attention, consult accompanying documents (IEC 348) This manual and the
relevant sections on the BioSemi Website (see references in this manual)
should be read before operating components showing this icon. |
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Type BF equipment (IEC 878-02-03) Components showing this
icon, are equipped with a Body Floating (BF) type Applied Part as defined in
international standard EN60601-1, clause 2.2.25. For more information, see
section 1.5 of this manual. |
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Conformité European This mark is a
declaration by the manufacturer that the respective component complies with
the relevant directives and standards as issued by the European Union. For more
information, see section 1.3 of these manual. |
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1.3 Certification |
The ActiveTwo system bears
the CE mark as a declaration of the manufacturer that the system meets the
applicable standard for electromagnetic compatibility (EU directive 89/336/EEC)
and electrical safety for the intended use as a biopotential measurement system
in research applications. The following standards apply:
EMC compatibility: EN61326 (1997) + A1 (1998) + A2 (2001)
Electrical Safety: EN 60601-1 (1990) + A1 (1993) + A2
(1993) + A13 (1996)
A declaration of conformity
is supplied with each ActiveTwo system
The conformity with the
standards was examined by an external test house (D.A.R.E consultancy,
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The
CE mark on the ActiveTwo system is not equivalent with the medical CE mark
found on Medical Devices (medical CE marks can be recognized by the
identification number of the responsible Notified Body). Although the
ActiveTwo system does comply with the demands for electrical safety used in
the Medical Device directive, the system does not comply with several other
requirements of the Medical Device directive 93/42/EEC. |
1.4 Intended purpose |
The BioSemi ActiveTwo
measurement system is designed to measure potential differences on the human or
animal body surface. The system is successfully used to record signals
originating from the brain (electroencephalography, EEG), the hart
(electrocardiography, ECG), and the muscles (electromyography, EMG) for research
purposes. The ActiveTwo system can be adapted to these different applications
by using different versions of the (active) electrodes. Besides body surface
potentials, the ActiveTwo system can acquire signals from a wide range of
additional sensors, in order to measure variables like body temperature, muscle
force, etc.
The ActiveTwo is designed,
and intended to be used as an instrument for scientific research only.
The electrophysiological data acquired with the ActiveTwo is meant to be used
within the framework of scientific research. The system is not intended for
medical applications. The system is not approved and allowed to be used for diagnosis of diseases or
treatment of disease, and the measured data shall not be used as a basis for
any medical action. The system is not certified as a Medical Device as defined
in EU directive 93/42/EEC, Article 1, Sec 2 (a) (European Union), or as defined
in the Federal Food Drug & Cosmetic (FD&C) Act, Chapter II, Sec 201 (h)
(
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The
BioSemi ActiveTwo system is not designed to be used for diagnosis or
treatment of disease. The intended use of the ActiveTwo is limited to
scientific research. Using the ActiveTwo system as a tool for diagnosis
or treatment may harm subjects |
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Because the ActiveTwo is designed as an instrument for
research, it offers a flexibility that cannot be offered in a system designed
for patient treatment. For example, the hardware configuration and the open-source
software are highly configurable to adapt the system to various demands of different
research applications. This flexibility, however, also allows the user to
choose configurations and/or software modifications that lead to corrupted
data being measured. This is the mains reason that the system shall not be
used for diagnosis or treatment of patients. Moreover, the system is meant to
be used only by skilled professionals. |
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1.5 System layout |
The ActiveTwo system is
based on the concept of optimal galvanic isolation between a front-end
connected to the subject, and a back-end consisting of further signal
processing hardware. For a diagram of the principle please see www.biosemi.com/pics/zero_ref1_big.gif.
Front-end: Section of the system consisting of Active Electrodes (2.1), AD-box
(2.2) and Battery-box (2.3). The
front-end is galvanically connected to the subject; the front-end is
galvanically isolated from the environment (other equipment, mains power supply
and safety earth).
Back-end: Section of the system consisting of Charger (2.4, Receiver
(2.5), and Personal Computer with
data-acquisition software (Part 2 of the manual). The back-end is galvanically
isolated from the subject; the back-end is not galvanically isolated from the
mains supply and the safety earth.
The ActiveTwo front-end is
designed to digitize the signals from 8 up to 256 active electrodes and other
sensors. The back-end processes the data: signals are displayed on a monitor
and saved to hard disk, and optionally further processed online. The digitized
data is transmitted from front-end to back-end via an optical fiber data link.
The optical fiber (glasfiber core, plastic sheath, good isolator) is the only
connection between the two sections of the system.
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The setup of the ActiveTwo, with battery power supply of
the front-ends, and fiber optic data transfer from front-end to computer,
ensures the lowest possible capacitance of the isolation barrier between the
isolated (floating) and non-isolated (connected to the safety earth) sections. The resulting isolation capacitance
is magnitudes lower than can be achieved with alternative designs, based on
optocouplers (data transfer) and DC-DC converters and/or isolation
transformers (power supply). The isolation capacitance determines the amount
of leakage current in both normal operation, and during several fault
conditions. Minimal leakage current during normal operation is essential for
the rejection of interference. Minimal leakage current in case of accidental
contact between the subject and mains supply voltages is an important safety
issue (http://www.biosemi.com/publications.htm). |
The setup of the ActiveTwo
system provides a BF (Body Floating) type isolation of the front-end, as
defined in standard EN 60601-1. This feature is indicated by the appropriate
symbol on the AD-box front-panel, please refer to section 1.3.
1.6 Safe use |
The safe use of the
ActiveTwo system is based on the galvanic isolation between the (battery
powered) front-end, and (mains powered) back-end. During the use of the system,
it is essential that this isolation barrier is not jeopardized by
modifications, connection of additional equipment, or any other form of misuse.
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Never short-circuit the galvanic isolation provided by the
optical fiber connection Do not
connect any mains powered equipment to the front-end. Do not connect the
front-end to the safety earth. Ensure that the subject cannot touch any part
of the back-end: keep back-end at least 1.5 meters removed from the subject. Use
only the original Battery-box as a power supply for the AD-box, do not
attempt to use alternative power supplies. |
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Consult BioSemi before making additional connections to
the AD-Box For all additional signal
sources interfacing with the ActiveTwo system, it is always necessary to
assure that the additional connection does not compromise the isolation of
the front-end. Therefore, all sensors connected to AD-box should be floating:
they should be powered by the AD-box or extra dedicated battery power supply,
and there should be no connection with any other (mains powered)
equipment. Signals sources that are
not isolated from the mains-supply, should interface with the trigger ports
on the ActiveTwo receiver, or with the additional Analog Input Box (AIB). |
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Do not treat the skin to attempt reducing the electrode impedance The active electrodes
used in the ActiveTwo system ensure that high quality measurements are
possible with high electrode impedances. Procedures such as scrubbing of the
skin, as is required with conventional electrodes, can therefore be skipped.
We strongly advise against skin scrubbing because it increases the danger of
infections. |
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The electrical safety of
the ActiveTwo system is based on the following principles: |
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Complete Front-end is
Body Floating (BF type isolation) Galvanic isolation
between Front-end (electrodes, AD-box and battery), and back-end (receiver
and PC). The Front-end is battery-powered, and the optical fiber for data
transfer is the only connection between Front-end and Back-end. The Back-end
is not located in the subject area (at least 1.5 meter away from the
subject). No part of the Front-end should ever be connected to the Safety Earth,
or to a mains powered system (battery connector design makes simultaneous
connection to AD-box and charger impossible) One-way communication
front-end to Back-end By single fiber
connection, the data stream only conducts from the Front-end to PC. The Front-end
runs independently from the PC, no sequential logic is implemented in the Front-end. CMS/DRL circuit for
subject grounding DRL is the only
low-impedance connection between the front-end (BF type applied part) and the subject, the current is limited by safety
resistors (current via the subject limited to 40 uA under Single Fault Condition),
all active electrode inputs have a high input resistance (> 1 GOhm) during
normal operation. Protection switch in
power supply to active electrodes The CMS/DRL circuit
detects when the currents flow via the subject is out of the normal operation
range (and always limits the current to 40 μA). In case of a problem,
the operator is warned (blue indicator LED off), and the power-supply to all active
electrodes is automatically switched off. Guard circuit driving all
accessible parts on front-end All accessible conductive
parts on the front-end are connected to a Guard circuit. The output current
of the Guard circuit is limited by safety resistors (the patient auxiliary
current is limited to less than 10 μA when subject touches any
accessible part of the front-end). Protection circuit senses voltage on accessible parts The AD-box shuts down
completely when the voltage on any accessible part is out of the normal
operation range. This shutdown protects the subject for current flow when a
defect AD-box would be touched. Examples of defects that will trigger the
shutdown circuit are: loose power wire contacting the internal shield, and a short
circuit between the shield and AD-box circuitry. |
1.7 Specifications |
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Sample-rate
options: (sample rate is adjustable by user) |
2048 Hz |
4096 Hz |
8192 Hz |
16,384 Hz |
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Max.
number of channels @ selected sample rate:
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256 |
128 |
64 |
32 |
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Bandwidth
(-3dB): |
DC - 400 Hz |
DC - 800 Hz |
DC - 1600 Hz |
DC - 3200 Hz |
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Low-pass
response |
5th order sinc digital
filter |
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High-pass
response |
fully DC coupled |
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Digitalization: |
24 bit, 4th order
Delta-Sigma modulator with 64x over sampling, |
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Sampling
skew: |
< 10 ps |
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Absolute
sample rate accuracy (over temp range: 0-70 C) |
0.1 Hz |
0.2 Hz |
0.4 Hz |
0.8 Hz |
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Relative
sample rate accuracy (jitter) |
< 200 ps |
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Quantization-resolution |
LSB = 31.25 nV, guaranteed no
missing codes |
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Gain
accuracy: |
1 % |
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Anti
aliasing filter |
fixed first order analog filter,
-3dB at 3.6 kHz |
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Total
input noise (Ze < 10 kOhm):, full bandwidth |
0.8 uVRMS |
1.0 uVRMS |
1.4 uVRMS |
2.0 uVRMS |
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1/f noise
(Ze < 1 MOhm): |
1 uVpk-pk @ 0.1..10Hz |
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Amplifier
current noise: |
< 30 fArms |
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Input bias
current: |
< 10 pA per channel |
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Input
impedance Active Electrode |
300 MOhm @ 50 Hz (1012 Ohm
// 11 pF) |
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DC offset: |
< 0.5 mV |
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DC drift |
< 0.5 uV per degree Celsius |
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Input
range |
+262 mV to -262 mV |
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Distortion |
< 0.1 % |
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Channel
separation |
> 100 dB |
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Common
Mode Rejection Ratio |
> 80 dB @ 50 Hz |
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Isolation
Mode Rejection Ratio |
> 160 dB @ 50 Hz |
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Power
Consumption |
4 Watt @ 256 channels |
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25 Watt-hour, 3 cell sealed
lead-acid |
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> 5 hours @ 256 channels |
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< 3.5 hours for a 100% charge |
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Leakage
current, normal operation: |
< 1 uA rms. |
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Leakage
current, single fault |
< 50 uArms |
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Trigger
inputs: |
16 inputs on optical receiver
(isolated from subject section) , TTL level |
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Trigger
outputs: |
15 outputs on optical receiver
(isolated from subject section) , TTL level |
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PC
interface: |
USB2.0 |
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Size of
front-end, including battery-box (H x W x D) |
120 x 150 x 190 mm |
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Weight of
front-end, including battery-box |
1.1 kg |
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Environment: |
Indoor use: Temperature: +10°C to
+40°C Humidity: 30 to 75%
Pressure: 700 hPa to 1060 hPa |
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Warranty |
3 years (1 year on electrodes and
batteries) |
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2.1 Active Electrodes |
The active electrodes
contain a Ag‑AgCl sintered electrode pellet, and a buffer amplifier with an
input protection circuit. The electrodes are sealed in a watertight resin. The
electrodes can be used in connection with all commercially available electrode
gels, but to achieve optimal results, we recommend the Parker Signa gel.
The integration of the
first amplifier stage on the electrode, allows impedance transformation on the
electrode (the active electrode has an output impedance lower than 1 Ohm). This
makes it possible to measure body surface potentials with via high electrode
impedances, without encountering the noise and interference problems seen in
measurements with high-impedance passive electrodes, see:
http://www.biosemi.com/publications/pdf/Interference_reduction.pdf
With the active electrodes,
procedures to reduce the impedance of the electrode-skin interface, such as
scrubbing of the skin as is required with conventional electrodes, can
therefore be skipped. This speeds up the application time considerably and
makes the measurement procedure much more comfortable for the subject. We
actually advise against scrubbing of the skin because is increases the danger
of infections, see section 1.6 (safe use)
The CMS (Common Mode Sense)
and DRL (Driven Right Leg) electrodes are used to drive the average potential
of the patient as close as possible to the AD-box reference potential, see www.biosemi.com/pics/zero_ref1_big.gif. The CMS electrode is best located approximately
in the center of the other electrodes (for example on the top of the head in
case of a typical EEG measurement). In practice however, the exact location is
not very critical though. The DRL electrode can be located anywhere on the body.
The DRL and CMS electrodes
are part of o feedback loop. The feedback loop needs to be closed to be able to
drive the subject to a potential close to the AD-box reference. If the loop is
working properly, the Common Mode (CM) voltage (the average potential of the
subject) is within the normal input range of the AD-box. This normal operation
condition is indicated by the blue indicator LED (CM in range) being
illuminated. The blue indicator can be found on the AD-box front-panel (see
2.2), and on the ActiView panel (see Part 2, software).
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CM can only be in range by having both the DRL and CMS
electrodes properly connected to the subject As long as the loop is
not closed, the blue indicator LED will remain off. In case of CM in range
problems, always make sure to check first that the blue LED comes on with
only the CMS and DRL electrode making contact with the subject (all other electrodes
left unconnected) |
The watertight sealing of
the electrode circuitry and cable is essential for proper operation of the
system. If the electronic circuitry of the electrodes is not completely sealed,
(conductive) electrode gel and/or subject perspiration may creep into the
circuit, and cause an internal short circuit.
If the cable isolation is damaged, the bare core may touch the subject
body. Finally, if one of the leads of an active electrode is interrupted (core
breakage, connector problem, etc.) the input circuitry of the electrode is not
properly biased. If any of these conditions occurs, leakage current will try to
flow from defect electrode or cable, via the subject body, and via the DRL
electrode back to the AD-box. The DRL drive circuit will limit this current to
a safe value (40 μA), detect that the current flowing through the subject is
out of the normal operation range, and the power-supply to all active electrode
will be switched off automatically. This action of the protection circuitry is
indicated by the blue indicator LED (CM in range) on the AD-box going off. As
long as the blue indicator LED is not illuminated (Common Mode voltage is not
in range), no valid measurements will be possible on any of the channels.
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Valid measurement are only possible when CM is in range, (blue
LED illuminated) Any defect on electrodes,
cables or connectors that forces the current via the subject to be out of the
normal operation range causes the power to all active electrodes to be
switched off automatically as a safety measure. The problem has to be
corrected before the measurement can continue. Test the electrodes in salt
water to find the defect, as explained in section 3.2 |
The active electrode are
available in different versions, please refer to www.biosemi.com/active_electrode.htm
for more details
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Avoid contaminating connectors with electrode gel Electrode gel is
specially made to achieve good conductivity. Contaminating the connectors with
gel may cause short circuits. Such a short will trigger the safety circuitry,
and the blue indicator LED (CM in range) will remain off displaying an error.
Clean the connectors as explained in section 3.2 |
2.2 AD-box |
Front of the AD-box
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Top of the AD-box
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The electrode signals are
amplified and converted from analog to digital format in the AD‑box. The
amplifier/converter circuits are integrated on 8 channel modules, the AD-box
can be equipped with up to 32 of these modules. This allows the AD-box to be
configured for operation with 8 to 256 channels (in steps of 8). All digital
data is multiplexed into a serial data stream, and sent to the signal
processing PC via an optical fiber.
Under normal operation, the
green LED is on (showing that the power-supply circuitry operating properly),
the blue LED is on (Common Mode in range, CMS and DRL electrodes properly
connected, no defective electrodes or cables), and the red LED is off (battery
sufficiently charged). When the battery voltage is running low, the red
indicator LED will illuminate. At that time, there is 30-60 minutes operational
time left (depending on the number of installed channels), before the shut-down
circuitry in the
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Signal quality is not affected when “low battery” is
indicated The shutdown circuitry in
the Battery-box operates at a voltage where there is still sufficient power
available for the circuitry in the AD-box. As long as the shutdown is not
triggered, the data quality is assured. The “low battery” warning is given
30-60 minutes prior to the moment of shutdown. |
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The AD-box power circuits shut down when the voltage of
the accessible metal parts is not within the normal operating range This is a safety feature
to detect a loose wire inside the box touching the box shield. The safety
circuit can be reset by switching the power off and on again. If this does
not solve the problem, stop the experiment, and return the AD-box to BioSemi (or
its local representative) for repair. |
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The condition of all (3) indicator LEDs blinking,
indicates a short circuit inside the AD-box Switch off the power, and
disconnect the electrodes. Return the AD-box to BioSemi (or its local
representative) for repair. There is no immediate danger for the subject
because of the CNS/DRL and Guard circuit safety resistors, and because the
power to the active electrodes is shut off. |
Speed-mode settings
Note: When an AIB is
connected, the AD-box should always be on SpeedMode 4. |
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The rotary switch can be
used to select 8 different speedmodes for the AD-box (speed-mode 9 is reserved
for use as Analog Input Box). Use a small screwdriver to rotate the switch to
the preferred number according to the table above.
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After changing the speed-mode, switch the AD-box off and
on again to reset the ADCs Changing the speed-mode
having the power connected is not harmful to the electronic circuitry, but
the synchronization between channels may be lost. |
The acquisition software
adjusts automatically to the selected speed-mode (check the indicator in the
“about ActiView” tab page). It is recommended to restart the ActiView software
completely after changing the speedmode, to prevent selectors from remaining
disabled in the new speed-mode. For more information, please refer to Part 2 of
the manual (software)
2.3 Battery-box |
Front of the Battery-box
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The Battery-box contains a
sealed lead‑acid battery (6 Volt) and a shut‑down circuit. The
shutdown circuit protects the battery for deep discharge, which would shorten
the battery life. When the battery voltage is running low, there will first be
a warning on the AD-box front panel (red indicator LED illuminated) and on the
ActiView software panel on the computer screen (pop-up window, and illuminated
red indicator light). At this moment, there is 30-60 minutes operational time
left (depending on the number of installed channels). After that time, the
shut-down circuit in the Battery-box will disconnect the AD-box from the
battery.
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The shutdown circuit may be triggered by connecting the
Battery-box to the AD-box with the power switched ON Switch the power OFF, and
ON again to reset the shutdown circuitry. |
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Replace the fuse when the green indicator LED (power) does
not illuminate with the power switched on (fisheye inside the button shows
green) Use a 5 Amp slow blow
type. If the problem persists, the Battery-box should be returned to BioSemi (or
its local representative) for repair. |
The batteries can be
recharged irrespective of the state of charge (there is no memory effect). The
service life of the batteries is decreased if they are left for long periods of
time in a state of low charge. Therefore: recharge the batteries soon after the
shut‑down circuit has been triggered (within a day or so), charge the
batteries fully before prolonged storing, and recharge stored batteries every 6
months. The batteries are rated for approx. 1000 full charge‑discharge
cycles. When the capacity of the battery starts to decrease (both charge and
discharge times decrease), the battery is approaching the end of its service life;
please return the Battery‑box to BioSemi (or its local representative) for
replacement of the cells.
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Use only the Charger type as originally provided with the
ActiveTwo system The provided Charger is
designed to deliver the correct charging voltage and current for the batteries.
Using any other charging method may damage the battery, or even result in a
dangerous situation. |
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The setting of the power switch on the Battery-box makes
no difference during charging The power switch is by-passed
during charging, it is not necessary to switch the Battery-box to the
position ON during charging. |
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After the useful service live, return the Battery-box to
BioSemi (or its local representative) for replacement of the cells Alternatively,
use a disposal method according to the regulations in your territory for
lead/acid batteries. Never dispose of the batteries as normal household
waste. Do not attempt to disassemble the Battery-box, or to open sealed
lead/acid cells. |
2.4 Charger |
Charger
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The charger is capable to
fully charge a battery within 3 to 4 hours. During the charge cycle, the
indicator LEDs will go from “full charge” to “trickle charge”, and finally to
“ready”. The red LED indicates that the battery is being charged, this LED will
come on when a battery is connected that is not fully charged (anything between
90% and 0% charge). The yellow LED indicates that the battery is 90% charged.
The last 10% may take relatively long: approx. 1 hour at the most. The battery
can be re-used when the yellow LED comes on, but it is recommended to charge
the battery fully (until the green LED comes on) once in a while.
The Charger switches to
stand-by current when the green indicator LED comes on. The Battery-box can be
left connected to the Charger for indefinite periods of time; there is no
danger for over-charging. Leaving the Batteries-box connected to the Charger on
stand-by current for long periods of time (days) ounce in a while, actually helps
to prolong battery life. Typically, one of the two Battery-boxes provided with
the ActiveTwo system would be connected to the Charger, where the other one
would be in use as power supply for the AD-box. The batteries would then be
swapped at the time a low remaining power capacity for the battery in use is
indicated by the “low battery” indicator LED on the AD-box.
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Use only the wall adapter as provided with the ActiveTwo
system The Charger is designed
to only work in combination with the supplied mains adapter (Friwo FW7301/09).
Using any other power-supply for the Charger, or may lead to damage of the
Charger, and/or a connected Battery-box, or may even result in a dangerous
situation |
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Leave the Charger connected to the power-supply when a Battery-box is connected When the Charger is OFF, the
battery will slowly discharge via the Charger’s internal circuitry. As long
as a Battery-box is connected, do not disconnect the Charger from the mains
adapter, and do not unplug the mains adapter from the wall socket. |
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Ayn abnormally long charging time would indicate a defective
Battery-box When full charging (red indicator
LED) prolongs beyond approx. 6 hours, and/or the |
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The provided mains adapter is a world-wide version. The mains adapter can be
used with mains voltages between 100 and 240 Volt, with a frequency between
47 and 63 Hz. This makes the mains adapter suitable for mains supplies in
virtually any country in the world. Different mains plugs can be fitted to
the adapter to comply to various types of connector world-wide used. |
2.5 Receiver |
USB Receiver
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The receiver converts the
optical data stream form the AD-box into an USB2 compatible signal to the PC.
In addition, trigger input signals are added to the data stream see http://www.biosemi.com/faq/trigger_signals.htm.
In addition, the receiver can sent output pulses via the trigger port. Finally,
the sample-rate frequency is available at the trigger port for synchronization
purposes.
Layout of the Trigger
input/output connector on the USB receiver.
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Pin01 = Trigger input 1 |
Pin11 = Trigger input 11 |
Pin21 = Trigger output 5 |
Pin31 = Trigger output 15 |
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Pin02 = Trigger input 2 |
Pin12 = Trigger input 12 |
Pin22 = Trigger output 6 |
Pin32 = Sampling frequency |
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Pin03 = Trigger input 3 |
Pin13 = Trigger input 13 |
Pin23 = Trigger output 7 |
Pin33 = n.a. |
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Pin04 = Trigger input 4 |
Pin14 = Trigger input 14 |
Pin24 = Trigger output 8 |
Pin34 = n.a. |
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Pin05 = Trigger input 5 |
Pin15 = Trigger input 15 |
Pin25 = Trigger output 9 |
Pin35 = n.a. |
|
Pin06 = Trigger input 6 |
Pin16 = Trigger input 16 |
Pin26 = Trigger output 10 |
Pin36 = n.a. |
|
Pin07 = Trigger input 7 |
Pin17 = Trigger output 1 |
Pin27 = Trigger output 11 |
Pin37 = Ground |
|
Pin08 = Trigger input 8 |
Pin18 = Trigger output 2 |
Pin28 = Trigger output 12 |
|
|
Pin09 = Trigger input 9 |
Pin19 = Trigger output 3 |
Pin29 = Trigger output 13 |
|
|
Pin10 = Trigger input 10 |
Pin20 = Trigger output 4 |
Pin30 = Trigger output 14 |
|
The receiver is powered
form the PC power supply via the USB connecting cable. With the receiver
connected to the PC, the optic data LED indicates whether data is received from
the AD-box. In case the data LED remains off, check the fiber connection and
AD-box power indicator.
The USB data LED
illuminates when the USB handshake between receiver and USB is established. The
handshake is operational during data acquisition with the ActiView software
(press the “start” control, see Part 2 of the manual: software). In case the
USB data LED remains off, check the installation of the USB device drivers
(Part 2 of the manual), and check that
the USB port on the PC meets the USB version 2.0 specification (USB1 is too
slow to handle the ActiveTwo data throughput, the handshake will not be
established).
|
|
The receiver connects to both desktop and laptop
computers. The USB port should meet the
2.0 specification, operating system should be Windows XP (the provided USB
drivers work only under XP), the processor should be a Pentium IV running at
a minimum of 1 GHz (> 2 GHz is recommended), and the screen resolution
should be at least 1280*1024 (1600*1200
is recommended). |
3.1 General Maintenance |
The ActiveTwo system
contains no user-serviceable components.
|
|
Unauthorized repairs or modifications to the Front-end
components may cause a safety hazard. Always return
malfunctioning Front-end components to BioSemi (or its local representative)
for inspection and/or repair. |
|
|
Clean the system components with a slightly damp soft
cloth, It is permitted to use a
mild soap solution if necessary, nut never use aggressive or abrasive
cleaners or solvents. Use any cleaning fluid sparingly. Prevent any fluid
from entering the connectors or enclosures, and let the devices dry
completely before putting the same into service again. |
|
|
It is not necessary to adjust or calibrate the system
during its normal service life (10 years). |
3.2 Electrode handling |
Four Rules of thumb:
1) Clean
electrodes softly immediately after
use (when the gel is still soft) by hand with warm water.
2) Dry the electrodes softly, with
hand paper, Store the electrodes in
a dark dry place.
3) Do not use aggressive soaps etc, do
not let the pellets touch any kind of metals.
4) Do not let
water or gel enter the connector.
Handling
Do not use force on the
cable when
removing the electrode out of the headcap or the connector out of the AD-box.
Grab the electrodes at the casing, and then pull them softly out
of the headcap. The AD-box has ejectors on the top for easy
removal of the connector. Always make sure to use them. Keep the connector clear of water/gel. When
a connector is polluted with gel or salt water, it should be rinsed with
distilled water, followed by a rinse with alcohol (ethanol) and finally the
connector should be allowed to dry completely before putting into operation
again.
After applying the
electrodes, it takes some time before the chemical reactions in the
electrode-gel-skin interface have reaches a stable equilibrium. It will
typically take approx. 5 minutes before baseline drift and noise have settled
to a low figure. Quicker settling of the electrode noise to a low level can be
achieved by placing the electrodes in water approx. 1 hour before the
measurement is started. During this hour, the salt water will be absorbed in
the AgAgCl pellet, enabling the pellet to make better chemical contact with the
gel.
Cleaning
The silver/silver-chloride
(AgAgCl) sintered electrodes behave like sponges, they absorb water and
electrode gel. The deeper the water/gel has penetrated the electrode, the
longer it will take afterwards for the water to vaporize. As long as your
electrodes are ‘wet’, corrosion processes will take place. This corrosion
process will in the long run make your electrodes noisier. That’s why it’s
important to clean the electrodes
immediately after use and then let them dry quick, allowing corrosion no
change.
Use warm tap water to rinse off the gel from the electrodes (make
sure to keep the connector dry). Warm water (up to 50 degrees Celsius) will
dissolve the gel quicker. Use a soft brush for removing gel residues from
the electrodes only if absolutely necessary. Softly dry the electrodes with
hand paper. Let them hang out to dry. Only use (mild) soap if water alone does
not seem to clean the electrodes properly. Do not let the electrodes dry
without being cleaned first. When the electrodes dry up covered with gel/salt/minerals,
your electrodes may become polluted and/or corroded sooner.
Storage
Do not store the electrodes
in a metal box. In general, prevent the electrode tips from touching any metal
objects, because this may cause pollution of the Ag/AgCl pellets with “strange”
metal particles (increasing noise). Exposure of the AgAgCl electrode tip to light
also causes deterioration. Keep out of direct sunlight or other bright sources of
light when the electrodes are not being used. Do not store the electrodes in an
airtight container. Best storage method is to wrap the electrodes in a paper
towel and place them in a cardboard box or to hang them freely in a dark place.
Modifications / Splitting of the cable
The electrodes are not intended
to be modified by the customer. Especially "splitting"
the flat-cable further may lead to a non-repairable malfunction and void
your warranty! If you have a request for different splitting of an electrode
set contact BioSemi (or its local representative)
Malfunctions
If an electrode is not
operating as specified, please do the following:
Soak
the electrodes in water with some salt added (approx. one small teaspoon
per liter, use a non-metal bowl)
- If this causes the blue
led to turn off, then the electrode set is in need of repair, please return it
to the dealer/manufacturer.
- If you experience noise, then please follow-up
the directions below concerning noisy electrodes.
Noisy electrodes: (also read “Life span”)
Noisy electrodes generally mean that your electrodes have reached its end of
life. You can extend the life a little bit by placing the electrodes in salt
water for a few hours before you start your measurement. This soaking process
often removes noise within a few hours. A last remedy is to use a grain 600 or
higher waterproof abrasive paper to polish the electrode tip. Use very soft circular
movements, preferably no more than 2-3 times on the same area, removing an even
very thin layer across the entire surface.
Life span (Life expectancy)
Ag-AgCl sintered electrodes
have a limited life span. This is caused by several processes such as the dissolving
of the Chloride in the pellets and the wearing of the pellet during the
cleaning process. After approximately 200 measurements, the color of the pellets
will change from gray/brown (silver–chloride) to silver, due to the disappearing
of the chloride. The AgCl slowly dissolves in gel and water during the
cleaning. Eventually, this leaves only silver behind. The resulting pure silver
electrode has much higher drift and noise than the original Ag/AgCl electrode, forcing
your electrode set to be replaced.