background image

40

PowerLab Owner’s Guide

bus

. A data-carrying electrical pathway. 

Chart

. An application supplied with a 

PowerLab that emulates a multi-channel 
chart recorder, with other powerful options. 
(Macintosh and Windows versions differ.)

connector

. A plug, socket, jack, or port used 

to connect one electronic device to another 
(via a cable): a PowerLab to a computer, say.

CPU

 (central processing unit). A hardware 

device that performs logical and arithmetical 
operations on data as specified in the 
instructions: the heart of most computers.

DAC

 (digital-to-analog converter). A device 

that converts digital information into some 
corresponding analog voltage or current.

DC offset

. The amount of DC (direct current) 

voltage present at the output of an amplifier 
when zero voltage is applied to the input; or 
the amount of DC voltage present in a 
transducer in its equilibrium state.

differential input

. Input using both positive 

and negative inputs on a PowerLab. The 
recorded signal is the difference between the 
positive and negative input voltages: if both 
were fed exactly the same signal, zero would 
result. Can reduce the noise from long leads.

digital

. Varying discretely. A digital signal 

changes to discrete values rather than 
varying continuously. A digital time display 
might read 2:57 instead of using the positions 
of a pair of hands on a clock face. 

DIN

 (Deutsche Industrie Norm). A sort of 

cable or connector; there are various sorts 
with different numbers of pins. 

envelope form

. The overall shape of a signal, 

outlined by the minimum and maximum 
recorded values. Often used to display 
quickly changing signals.

excitation voltage

. The voltage supplied to a 

bridge circuit from which the transducer 
output signal is derived. Manipulating the 
transducer changes the measurement 
elements of the bridge circuit, producing a 
change in its output voltage.

external trigger

. The input connector on the 

front of the PowerLab marked ‘Trigger’. This 
lets one start recording from an external 
source. The trigger level (the voltage needed 
to have an effect) depends on the hardware 
and cannot be changed. The /20 series 
PowerLabs can also be triggered by contact 
closure if this is set up in the software. 

filter

. An electronic device or a program that 

alters data in accordance with specific 
criteria. Filters in hardware and software can 
be used to reduce or to eliminate electronic 
noise or drift from data readings.

frequency

. The number of complete cycles 

per second of a waveform. Frequency is 
usually expressed in hertz, Hz (cycles per 
second), kilohertz, kHz (thousands of cycles 
per second), or megahertz, MHz (millions of 
cycles per second). 

frequency response

. The bandwidth in 

which a circuit passes a signal without too 
much attenuation. A low-pass filter’s 
frequency response is the frequency where 
the output voltage becomes 0.707 (1/

2) of 

the input voltage or has been attenuated by 3 
decibels. If a low-pass filter has a frequency 
response of 200 Hz, say, then the signal is 

Содержание PowerLab 2/20

Страница 1: ... r u m e n t s PowerLab 20 Owner s Guide for PowerLab 2 20 and PowerLab 4 20 models 4 20 Power Status ADInstruments Trigger PowerLab Output Input 1 Input 2 Input 3 Input 4 2 20 Input 1 Input 2 Power Status ADInstruments Trigger PowerLab Output ...

Страница 2: ...h and PowerBook are registered trademarks of Apple Computer Inc iMac is a trademark of Apple Computer Inc PowerPC is a trademark of International Business Machines Corporation Pentium is a registered trademark of the Intel Corporation Windows and Windows 95 are registered trademarks of Microsoft Corporation Windows NT is a trademark of Microsoft Corporation All other trademarks are the properties ...

Страница 3: ... Test 12 The USB Connection 13 Connecting the PowerLab Using USB 14 USB Connection Rules 15 A Technical Aspects 17 How Does it Work 17 The Analog Inputs 20 PowerLab Accuracy 22 The External Trigger 22 The Analog Output 24 Connections 24 USB Port 24 I2 C Expansion Port 25 Pod Connectors 25 Serial Port 26 B Troubleshooting 27 Problems Macintosh 27 Problems Windows 29 C Specifications 33 PowerLab 2 2...

Страница 4: ...iv PowerLab Owner s Guide ...

Страница 5: ...Amp ML117 BP Amp and ML180 front ends conform to international safety requirements Specifically these requirements are IEC601 1 and its addenda Table S 1 and various harmonised standards worldwide UL2601 1 in the USA and AS NZS3200 1 in Australia and New Zealand In accordance with European standards they also comply with the electromagnetic compatibility requirements under EN60601 1 which encompas...

Страница 6: ...he required ground connection to the power outlet If your building does not have power outlet sockets with a good ground connection then you may use the ground connection on the rear of the PowerLab to provide the equipotential connection to the building s earth conductor A ground connection is an essential part of this equipment s safety Never use the PowerLab without a ground connection Safety S...

Страница 7: ...ion If you need to clean peripherals likely to be in contact with different subjects they can be cold sterilised with an appropriate sterilising agent No part of the system can be autoclaved Storage It is recommended that the hardware be kept below 40 C and above 0 C in a moisture free or low humidity environment when not in use storage only Electronic components are susceptible to corrosive subst...

Страница 8: ...ent leakage and auxiliary currents and power cable integrity can all be performed on the PowerLab system without having to remove the covers You should follow the instructions for the testing device if performing such tests If the PowerLab system is found not to comply with such testing you should contact your PowerLab dealer to arrange for the equipment to be checked and serviced You should not a...

Страница 9: ...pecialised application programs provides a versatile data recording and analysis system when used with a Windows or Macintosh computer This chapter provides an overview of the PowerLab system and describes the basic features connectors and indicators of the 20 series PowerLabs the PowerLab 2 20 and PowerLab 4 20 ...

Страница 10: ...ding unit yourself you void any rights you have under warranty The user s guides for the Chart and Scope application programs provide detailed information on the software side of the PowerLab system and its uses in acquiring storing and analysing data Read them after you have connected the PowerLab to your computer First Check Your PowerLab Please do not attempt to connect the PowerLab to a power ...

Страница 11: ...rograms such as Chart and Scope that run on the computer to which the PowerLab is connected Your 20 series PowerLab has considerable computing power of its own and performs many tasks that are necessary during data recording Once the PowerLab transfers the data to the computer the data are available for display manipulation printing storage and retrieval The PowerLab 2 20 has two inputs for record...

Страница 12: ...ab to extend the system s capabilities They afford extra signal conditioning and other features and extend the types of experiments you can conduct and the data you can record Front ends are advanced signal conditioners the Bio Amp front end for instance lets you perform electrically isolated measurements of biological signals They are automatically recognised by the PowerLab system and integrated...

Страница 13: ...wo alternative pod DIN connectors for recording external signals The PowerLab 4 20 has three indicators at the left of the front panel one BNC connector for the external trigger two BNC connectors for output and four BNC connectors marked Input 1 to Input 4 with two alternative pod DIN connectors for Input 1 and Input 2 for recording external signals 2 20 Input 1 Input 2 Power Status ADInstruments...

Страница 14: ... suit your requirements using the software Note that applying more than 15 V to the analog inputs can damage the circuitry The PowerLab 2 20 has two independent analog inputs marked Input 1 and Input 2 each of which has alternative connectors The PowerLab 4 20 has four independent analog inputs marked Input 1 to Input 4 the first two of which have alternative connectors In either case the top BNC ...

Страница 15: ...V signal then the negative output will simultaneously give a 5 V signal The outputs cannot be run independently If only the positive output socket is used a positive stimulus voltage set up in the software will give a positive voltage output and a negative voltage a negative one When the negative output socket is used the voltage outputs are inverted When both output sockets are used the stimulus ...

Страница 16: ...ith ADInstruments front ends Only 50 mA maximum current can be provided through this bus so it should not be used for third party devices drawing more current USB Port The PowerLab connects to your computer using a USB universal serial bus port This works with USB 1 1 compliant computers with USB connectors or a PCI USB card To operate USB needs a Power Macintosh running Mac OS 8 5 or later or a P...

Страница 17: ...e used instead The ground connector post on the rear panel is used as a primary earth connection equipotential connection point in situations that require this type of connection or if there is no ground provided via the power cord Safety standards in laboratories and similar environments may require additional grounding protection when connecting equipment to human subjects In such cases an equip...

Страница 18: ...10 PowerLab Owner s Guide must be returned for service by qualified service personnel Do not attempt to replace internal power supply fuses yourself ...

Страница 19: ...ner s Guide 11 C H A P T E R T W O 2 Setting Up This chapter starts with the PowerLab s internal self test then looks at how to connect up your PowerLab to a computer It discusses the USB connection in some detail ...

Страница 20: ...dicator should flash yellow and then stay green The Trigger indicator should flash yellow and then turn off If the indicators perform as described above then your PowerLab has successfully performed its internal self test and it can be safely connected to your computer If your PowerLab would not successfully complete its self test something is wrong If the Power indicator does not glow blue when t...

Страница 21: ...Power Macintosh with Mac OS 8 5 or later but note that the latest PowerLab software requires Mac OS 8 6 USB devices are connected in a tree like structure with the host the computer forming the root of the tree and hubs allowing multiple devices to connect to them like the branches of the tree A hub is simply a device that lets you extend the USB tree It connects to a USB device such as the comput...

Страница 22: ...ables are high speed with fully shielded twisted pair cables and standard USB connections a narrow rectangular A plug at one end and a squarer B plug with a bevelled top at the other All devices that can act as hubs have high speed connections The PowerLab needs a high speed connection and is provided with a suitable cable Connecting the PowerLab Using USB Use the USB cable supplied with your Powe...

Страница 23: ...B cable from a reliable supplier never a cheap brand or something the workshop whipped up Your PowerLab is supplied with the proper USB cable If you need additional USB cables you should buy high speed cables fully shielded twisted pair and with standard USB connections for reliable results 3 Don t disconnect the PowerLab while a program is using it Disconnecting a PowerLab while it is sampling is...

Страница 24: ... on or off or disconnect or reconnect a USB connected PowerLab while the computer remains on as long as the application program Chart or Scope is off when you do it Although USB is a hot pluggable standard Windows 2000 may complain bringing up an alert The alert lets you install a control in your taskbar to avoid potential problems in future ...

Страница 25: ... various functions needed for data acquisition signal conditioning and pre processing It contains its own microprocessor memory and specialised analog amplifiers for signal conditioning The block diagrams in Figure A 1 and Figure A 2 show the essential elements of each PowerLab All sampling output and communication functions are controlled by an internal PowerPC microprocessor running at 60 MHz Th...

Страница 26: ...nd displays the data The external trigger input marked Trigger on the front panel allows either a voltage level or a contact closure to trigger recording Figure A 1 Block diagram of the PowerLab 2 20 PPC403 CPU 16 bit ADC 16 bit DAC RANGE CONTROL Switching Power Supply IEC Mains Input USBPort Comparator FLASH ROM 1M x 16 DRAM System Glue Chip 1 1 2 DifferentialInput Amplifiers MultiPort POD I C 5 ...

Страница 27: ...he external contact closure mode the trigger input will respond to a direct short between the centre pin and outer ring of the BNC This can be Figure A 2 Block diagram of the PowerLab 4 20 PPC403 CPU 16 bit ADC 16 bit DAC RANGE CONTROL Switching Power Supply Comparator FLASH ROM 1M x 16 DRAM MULTIPLEXER System Glue Chip 1 1 2 DifferentialInput Amplifiers 2 Single endedInput Amplifiers MultiPort PO...

Страница 28: ...e supplies and frequencies without the need to change voltage ranges This power supply is also internally protected in the case of a problem It is important to note that the PowerLab has a limited amount of power available for external devices Because of these power limitations you should not use the PowerLab as a power source for external devices other than those produced by ADInstruments The Ana...

Страница 29: ...hat may develop over time or between readings The operation of the input amplifiers is illustrated by the block diagrams below The input amplifiers can be set to pass both DC and AC signals or to pass only AC signals without passing DC signals Input impedance is one megohm 1 MΩ AC DC coupling control Instrument amplifier Channel control bus BNC Analog input Grounding and input selection 1 MΩ AC DC...

Страница 30: ...facilities It is recommended and sound practice to calibrate a measuring system from the transducer to the output After applying two known values to a transducer say at 20 and 80 of full scale and recording the signal you can use the units conversion feature of ADInstruments software to convert and display transducer readings in the appropriate units This will compensate for any minor inaccuracies...

Страница 31: ...ll not work The trigger source must be capable of supplying at least 1 mA of current to activate the trigger The equivalent circuit of the external trigger is basically an LED light emitting diode in series with a resistor the second diode shown below protects the optocoupler In the external contact closure mode the trigger input will respond to a direct short between the centre pin and outer ring...

Страница 32: ... are inverted When both output sockets are used the stimulus is the difference between the voltages at the positive and negative outputs you could generate up to a 20 volt pulse given a 10 V stimulus Connections This section of the appendix contains pinout and electrical details of some of the connectors fitted to the PowerLab You should read it carefully before attempting to connect cables other ...

Страница 33: ...as it has appropriate connections You should not attempt to run other external devices from the I2 C port it is designed for use only with ADInstruments front ends Only 50 mA maximum current can be provided through this bus so it should not be used for third party devices drawing more current Pod Connectors The pod connectors on Inputs 1 and 2 of the PowerLab 2 20 and PowerLab 4 20 are 8 pin DIN c...

Страница 34: ...al Port The PowerLab is fitted with an RS 485 serial communication port It is not currently in use but is meant for connection in the future to specialised devices controlled from the PowerLab system The serial port provides a differential bidirectional serial connection for external devices supporting the RS 485 standard The port also provides three power supplies and a ground signal 4 Negative 5...

Страница 35: ...er are connection problems Improper connections can result in a loss of all or some of a signal The PowerLab Status indicator light flashes red or red and yellow when the PowerLab is turned on Either there is a low level software or firmware problem if there are red and yellow flashes or an internal hardware problem has been discovered by the diagnostic self test performed by the PowerLab each tim...

Страница 36: ...e PowerLab back on again Turn on the computer and try using the software again The connected computer does not properly support USB USB needs a Power Macintosh with Mac OS 8 5 or later it simply will not work with earlier hardware such as a 68K Macintosh or earlier operating systems such as System 7 The computer hangs up while recording or there is data loss A poor connection between PowerLab and ...

Страница 37: ...med by the PowerLab each time it powers up Turn everything off and then after at least five seconds turn the PowerLab back on again This should clear a temporary problem If not then the software may have a serious fault and may need to be reinstalled or the PowerLab may need repair Consult your ADInstruments distributor When Windows starts up it doesn t recognise the PowerLab This should happen on...

Страница 38: ...s 2000 may complain though bringing up an alert The Windows 2000 alert lets you install a control in your taskbar to deal with this Install the control and use it before you disconnect or turn off the PowerLab to avoid the alert The computer can t find the PowerLab The PowerLab is off or the power is switched off at the wall the power cable is not connected firmly or a fuse has blown Check switche...

Страница 39: ... again If there is still a problem try a new cable The PowerLab doesn t work or the program crashes after a short time A poor connection between PowerLab and computer or bad cable Ensure that the cable is firmly attached at both ends and try again If there is still a problem try a new cable Signals seem weak or interacting on Input 1 or 2 You may be using both the BNC connector and the Pod connect...

Страница 40: ...32 PowerLab Owner s Guide ...

Страница 41: ...he pod connectors Amplification ranges 2 mV to 10 V full scale in 12 steps 10 V 5 V 2 V 1 V 0 5 V 0 2 V 0 1 V 50 mV 20 mV 10 mV 5 mV 2 mV Maximum input voltage 15 volts Input impedance 1 MΩ 47 pF DC Low pass filtering 20 kHz fixed second order filter Further digital filtering in software AC coupling DC or 0 1 Hz software selectable Frequency response 3 dB 20 kHz 10 V full scale all ranges ...

Страница 42: ...g inputs Connector type 8 pin DIN Sampling ADC resolution 16 bits 150 µV resolution at 10 V range Linearity error 2 LSB from 0 C to 70 C Maximum sampling rates 100 kHz on one channel 40 kHz on two channels Available sampling rates 100 kHz down to 0 003 Hz using Chart 100 kHz down to 2 Hz using Scope 100 kHz to 1 Hz using Chart for Windows Output Amplifier Output configuration Single ended or diffe...

Страница 43: ...rocessor PPC403 GCX 60 MHz internal Memory 4 MB DRAM Data communication USB up to 800 kilobytes s possibly greater dependent on setup Expansion Ports I2C expansion port Power and control bus for front end units Supports up to 16 front ends but limited to the PowerLab s free connectors Interface communications rate of up to 10 000 bits s Physical Configuration Dimensions w h d 200 mm 65 mm 250 mm 7...

Страница 44: ...Amplification ranges 2 mV to 10 V full scale in 12 steps 10 V 5 V 2 V 1 V 0 5 V 0 2 V 0 1 V 50 mV 20 mV 10 mV 5 mV 2 mV Maximum input voltage 15 volts Input impedance 1 MΩ 47 pF DC Low pass filtering 20 kHz fixed second order filter Further digital filtering in software AC coupling DC or 0 1 Hz software selectable Frequency response 3 dB 20 kHz 10 V full scale all ranges DC drift Software correcte...

Страница 45: ...70 C Maximum sampling rates 100 kHz on one channel 40 kHz on two channels 20 kHz on three or four channels Available sampling rates 100 kHz down to 0 003 Hz using Chart 100 kHz down to 2 Hz using Scope 100 kHz to 1 Hz using Chart for Windows Output Amplifier Output configuration Single ended or differential complementary Output resolution 16 bits 150 µV resolution at 10 V range Maximum output curr...

Страница 46: ...s I2C expansion port Power and control bus for front end units Supports up to 16 front ends but limited to the PowerLab s free connectors Interface communications rate of up to 10 000 bits s Physical Configuration Dimensions w h d 200 mm 65 mm 250 mm 7 9 2 6 9 8 excludes connectors Weight 2 4 kg 5 lb 3 oz Operating voltage 90 260 V AC 50 60 Hz Nominal power needs 6 VA 25 mA 240 V or 52 mA 115 V no...

Страница 47: ...eps analog input This refers to the connectors on the front of the PowerLab marked Input These inputs are designed to accept up to 10 volts Inputs can be either single sided or differential the latter only in the case of the pod connectors analog output This refers to the connectors on the front of the PowerLab marked Output The analog output provides a software controlled variable output 10 V tha...

Страница 48: ... of cable or connector there are various sorts with different numbers of pins envelope form The overall shape of a signal outlined by the minimum and maximum recorded values Often used to display quickly changing signals excitation voltage The voltage supplied to a bridge circuit from which the transducer output signal is derived Manipulating the transducer changes the measurement elements of the ...

Страница 49: ...ternational Electrotechnical Commission low pass filter LPF A filter that passes low frequency signals and DC voltages but filters high ones attenuating frequencies above a certain value the cutoff or 3 dB frequency Macintosh A family of Apple computers with built in graphics and an elegant user interface A Power Macintosh and Mac OS 8 5 or later are needed to use USB and thus needed to use the 20...

Страница 50: ...ly SCSI devices can be linked together in a chain and require termination to preserve signal integrity Not used by the 20 series PowerLabs serial A connection protocol for sending information sequentially one bit at a time over a single wire TChart A simplified version of the Chart program once used for teaching Its manual of experiments is now available for Chart transducer A physical device that...

Страница 51: ...5 pod 6 7 25 26 PowerLab to computer 13 16 safe to humans 7 20 safety v viii USB 13 16 24 contacting ADInstruments ii D DAC digital to analog converter 20 DC drift 21 digital to analog converter 20 E equipotential connection 9 error patterns 12 13 external trigger 7 18 20 22 23 F front panel 5 7 front ends 4 G ground connection 9 I I2C port 7 8 25 26 M maintenance vii N New Hardware wizard 29 P po...

Страница 52: ...osh 27 29 Windows 29 31 S safety v viii 7 20 Scope 4 self test 12 13 serial port 9 26 Status indicator 6 12 storage vii T technical specifications PowerLab 2 20 33 36 PowerLab 4 20 36 38 transducers 4 trigger 7 Trigger indicator 6 7 U USB cables 15 connection 13 16 24 connection rules 15 16 port 8 24 25 user modification 17 W Warning Symbol vii ...

Страница 53: ...urposes for which it is suited and agree to take responsibility for their actions and the results of their actions If problems arise with an ADI product ADI will make all reasonable efforts to fix them This service may incur a charge depending on the nature of the problems and is subject to the other conditions in this Agreement Limitations ADI products are produced to high standards and should pe...

Страница 54: ...s altered Software License The Purchaser has the non exclusive right to use the supplied ADI software The Purchaser s employees or students for instance are entitled to use it provided they adhere to this Agreement The Purchaser can make as many backup copies of ADI software as is reasonable Each separate purchase of a software program however licenses it to be used on only one computer at any giv...

Отзывы: