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ADInstruments Bridge Amp Manual

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1. D lt Q 7 ML224 Quad Bridge Amp Output 4 Output 3 Output 2 utput i r ion No user serviceable parts inside i H n Refer servicing to qualified service personnel 9 Input 1 C Bus Output 1C Bus Output Input Z 00000 Mw f gt 090000 M oooo 7 bts oooo 9 Not intended for human connection unless connections marked appropriately Made in Australia by ADInstruments Pty Ltd Refer servicing to qualified service personnel Analog Output Sockets BNC sockets on the back panel of the Bridge Amp provide the signal outputs to connect to the analog input sockets on the front of the PowerLab The sockets are labelled Signal Output on a Bridge Amp and Output 1 to Output 4 or 8 on Quad or Octal Bridge Amps You don t have to match the channel numbers when connecting outputs to inputs but it helps to prevent confusion if you do A BNC to BNC cable is supplied for each connection Using Transducers Bridge Amps are designed to allow the PowerLab to connect to most DC bridge transducers including commonly available force pressure and displacement transducers temperature probes light meters and similar devices They are capable of supporting various powered transducers and certain low impedance unpowered or self powered transducers Artisan Te
2. A rtisan Artisan Technology Group is your source for quality Pee new and certified used pre owned equipment FAST SHIPPING AND SERVICE CENTER REPAIRS WE BUY USED EQUIPMENT DELIVERY Experienced engineers and technicians on staff Sell your excess underutilized and idle used equipment TENS OF THOUSANDS OF at our full service in house repair center We also offer credit for buy backs and trade ins IN STOCK ITEMS www artisantg com WeBuyEquipment A EQUIPMENT DEMOS HUNDREDS OF Instral e REMOTE INSPECTION LOOKING FOR MORE INFORMATION TO qii Remotely inspect equipment before purchasing with Visit us on the web at www artisantg com 7 for more our interactive website at www instraview com 7 information on price quotations drivers technical LEASING MONTHLY specifications manuals and documentation RENTALS ITAR CERTIFIED ee Mus Contact us 888 88 SOURCE sales artisantg com www artisantg com ADINSTRUMENTS making science easier Bridge Amp Owner s Guide E oa EH E E EH Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ADINSTRUMENTS This document was as far as possible accurate at the time of release However changes may have been made to the software and hardware it describes since then ADInstruments Pty Ltd reserves the right to alter specifications as required Late breaking information may be supplied separately Trademark
3. This section covers adapting transducers for use with the ADInstruments Bridge Amps To connect transducers that require some form of power supply from the Bridge Amp first read this section carefully The requirements of the transducer should be determined before attempting to connect it To adapt a transducer for use with the Bridge Amp you need to e set the excitation voltage for the transducer e wire the transducer to use the eight pin DIN plug Bridge Amp Owner s Guide E Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com You will need the following equipment asoldering iron and resin cored solder ONLY resin cored solder e aneight pin DIN style male plug with 45 degree pin spacing supplied with your Bridge Amp e common E12 resistors 0 25 or 0 125 Watt 2 or 1 metal film Setting the Excitation Voltage The first step in preparing a powered transducer for use with the Bridge Amps is to set the required excitation voltage Two of the pins in the Bridge Amp s DIN socket can provide up to 20 volts DC as excitation voltage to power the transducer The voltage is varied by a resistor fitted between the two corresponding pins of the transducer s DIN plug When no resistor is present the Bridge Amp s internal circuitry cuts off all voltage to prevent mishaps Once a resistor is fitted the correct excitation voltage is provided automatically when the transdu
4. 88 SOURCE www artisantg com Unpowered transducers or those with their own power supply do not have to be supplied with any excitation voltage from the Bridge Amp they supply their own signal to it directly The wiring connections should still be carefully checked before connection along with transducer impedance and output voltage Such transducers do not need the excitation range to be adjusted from the default setting If they have low output voltages though then it is possible that their offset ranges require adjusting Using Grass Transducers with DIN Bridge Amps Most Grass transducers should have an impedance of about 350 Q or so A few Grass and Grass compatible transducers have a much lower impedance of about 250 Q Bridge Amp Owner s Guide S Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com CH A PT EH EE Setting Up 1 EX This chapter describes connecting your Bridge Amp to your PowerLab and performing a quick test to make sure that it is working properly The best way to configure your system for one or more front ends is discussed along with how to use the Bridge Amp with ADInstruments application software Bl Chapter 2 Setting Up Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com PowerLab Requirements The ML221 ML224 and ML228 Bridge Amps will only operate with
5. 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 representative to arrange for the equipment to be checked and serviced Do not attempt to service the device yourself Environment Electronic components are susceptible to corrosive substances and atmospheres and must be kept away from laboratory chemicals Storage Conditions e Temperature in the range 0 40 C e Non condensing humidity in the range 0 95 Operating Conditions e Temperature in the range 5 35 C e Non condensing humidity in the range 0 90 Disposal e Forward to recycling center or return to manufacturer SN Safety Notes Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Bridge Amp Owner s Guide B Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com C HAPTER Overview The Bridge Amp is a modular device in a family called front ends designed to extend the capabilities of the PowerLab system The Bridge Amp is designed to allow the PowerLab to connect to most DC bridge transducers including commonly available force transducers temperature probes light meters displacement transducers pressure transducers and similar devices This chapter provides an overview of the various Bridge Amps describes their bas
6. including amendments 1 and 2 and 60601 1 2 and carry one or more of the safety symbols below These symbols appear next to those inputs and output connectors that can be directly connected to human subjects BF symbol Body CF symbol Cardiac Warning symbol see protected equipment protected equipment documentali The three symbols are e BF body protected symbol This means that the input connectors are suitable for connection to humans provided there is no direct electrical connection to the heart e CF cardiac protected symbol This means that the input connectors are suitable for connection to human subjects even when there is direct electrical connection to the heart e Warning symbol The exclamation mark inside a triangle means that the supplied documentation must be consulted for operating cautionary or safety information before using the device Further information is available on request Bio Amp Safety Instructions The Bio Amp inputs displaying any of the safety symbols are electrically isolated from the mains supply in order to prevent current flow that may otherwise result in injury to the subject Several points must be observed for safe operation of the Bio Amp Bridge Amp Owner s Guide E Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com e All Bio Amp front ends except for the ML138 Octal Bio Amp and PowerLab units with a built in Bio Amp
7. 4 Bridge elements resistors thermistors capacitors or a mixture negative excitation negative excitation The circuit forms a simple voltage divider If one of the elements changes value owing to an external stimulus the output voltage will also change In practice this configuration is not often used Half bridge transducers will require adapting with compensating resistors before use with a Bridge Amp Checking the Transducer Before attempting to connect any transducer to a Bridge Amp you will need to determine the three things listed below This information is normally supplied with the transducer if not you should consult the manufacturer or supplier of the transducer 1 Ifthe transducer requires an excitation voltage and if so what the maximum excitation voltage or recommended range is for the transducer The configuration of the transducer wiring connections 3 Ifthe transducer is a bridge type transducer and whether it has a full bridge or half bridge configuration Transducers supplied by ADInstruments are supplied pre adjusted and need no adjustment Do not attempt to connect the signal leads from the transducer to the Bridge Amp if the wiring configuration is not known Connecting an incorrectly wired transducer to an excitation source is likely to damage both the transducer and Bridge Amp B Chapter 1 Overview Artisan Technology Group Quality Instrumentation Guaranteed 888
8. further if fast spikes or peaks such as in the ORS complex of an ECC must be accurately recorded A high sampling rate however will use more computer memory and may limit recording time Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Bridge Amp Owner s Guide E Inverting the Signal The Invert checkbox allows you to invert the signal on the screen It provides a simple way to change the polarity of the recorded signal without having to swap the connections to the recording electrodes Invert For example you might be recording from a force transducer where an increase in force downwards gives a negative signal but you want to have a downwards force shown as a positive signal on the screen Checking the Invert checkbox will change the display to do this Offset Adjustment Transducers almost always produce some amount of signal usually small when in the equilibrium or rest state Offset from a zero reading need to be removed in a process called zeroing Commonly the user also wants to remove a constant term for example baseline blood pressure or initial tension in a muscle from a measurement of interest This enables more accurate measurement of the changes in the signal under stimuli The offset controls in the Bridge Amp dialog can be used to zero the reading manually or automatically Figure 2 5 Offset The Offset controls aia Offset 0 43 8 Windows
9. newer models of PowerLabs such as the SP 20 26 and 30 series Software Requirements The ML221 ML224 and ML228 Bridge Amps require the following versions of ADInstruments software applications e LabChart version 6 or later for Windows or Macintosh e Chart version 5 4 2 or later for Windows or Macintosh e Scope for Windows version 3 7 8 or later e Scope for Macintosh version 4 0 3 or later Note the Bridge Amps will not operate with earlier versions of these applications Free updates are available from the ADInstruments website for users with earlier versions of Chart 5 and Scope If you have queries regarding hardware and software requirements of the Bridge Amps please contact your local ADInstruments representative Connecting to the PowerLab Connect your Bridge Amp to the PowerLab as follows e Ensure that the PowerLab is turned off Failure to do this may damage the PowerLab the Bridge Amp or both e Connect the C output of the PowerLab to the I C input of the front end using the I C cable provided e Connect a BNC cable from each signal output on the rear of the Bridge Amp to an input on the front panel of the PowerLab Note that the Quad Bridge Amp acts just as if it were four individual Bridge Amps the Octal Bridge Amp eight The I C connections are internal though so there is only one IC cable needed to connect the Quad or Octal Bridge Amps to the recording unit Check that the plugs for the I
10. noise Excitation voltage range Zeroing circuitry Internal offsetting range Control Port C port Single ML221 Quad ML224 Octal ML228 Power requirements Operating conditions Transducer drive current Internal offset resolution Frequency response 3 dB 2 KHz maximum at all gains with the low pass filter off 100 dB 50 Hz typical lt 1 UV ms referred to input at highest gain Excitation and Zeroing 0 20 volts DC 10 V referred to ground adjusted by external resistor 45 mA maximum Software controlled either manual or automatic 10 V 1 V 5 V range 1 V 100 mV 500 mV range 100 mV 200 uV 50 mV 16 bit internal DAC 32 000 steps about 0 V 1 2 5 V 310 u V step 100 mV 200 mV 500 mV 31 u V step 200 u V to 50 mV 3 uV step Power and control bus for front end units Supports a number of front ends dependent on the PowerLab Interface communications rate of 50 kbits s Physical Configuration Weight and Dimensions h x w x d 50 mm x 76 mm x 260 mm 1 97 x 3 0 x 10 2 710g 60 mm x 200 mm x 250 mm 2 36 x 7 9 x 9 8 1 5 kg 60 mm x 300 mm x 300 mm 2 36 x 11 8 x 11 8 3 4 kg 0 8 W ML221 2 5 W ML224 5 0 W ML228 without transducer attached 5 35 C 0 90 humidity non condensing ADInstruments reserves the right to alter these specifications at any time Artisan Technology Group Quality Instrumentation Gua
11. offset The Offset is given in the units of the channel When the Bridge Amp is first powered up the software sets the offset circuit to its default position no offset adjustment of the transducer and the offset display value is zero When either Zero or the manual offset controls are clicked this value will change to indicate the positive or negative corrective adjustment On a Macintosh click the small O button to restore the offset circuit to its initial non zeroed position and the offset display value to zero This can be used to determine the offset generated by a transducer Display Offset Click Display Offset to display the Input Value dialog Figure 2 6 A voltmeter displays the voltage currently being measured for an input the input channel is indicated at the top of the dialog If a transducer or some other external equipment has offset adjustment capabilities you can use this to zero it Figure 2 6 The Input Value dialog Windows left and v Average Macintosh right Input 1 Offset x Value at Input 1 Because the dialog allows for such fine adjustment a vertical arrow appears indicating the zero point if the offset is substantial This dialog is not a control simply an indicator that acts like a voltmeter Bridge Amp Owner s Guide E Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Units Click Units to display the Units Conversi
12. record is limited by the transducer you use such information should be in the documentation supplied with it Low pass Mains Filter 20 25 and 30 series PowerLabs only The Mains filter checkbox allows you to filter out interference at the mains frequency typically 50 or 60 Hz Note that in general it is better to prevent interference at its source than to filter it The mains filter is an adaptive filter which tracks the input signal over approximately 1 second It analyzes the signal and creates a template of any interference due to the mains frequency see Appendix C Subtraction of the template from the incoming signal cancels most of the interference Mains filter Bl Chapter 2 Setting Up Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Anti alias In comparison with a notch filter this method produces little waveform distortion and attenuates harmonics of the mains frequency as well as the fundamental it effectively removes non sinusoidal interference such as that commonly caused by fluorescent lights The filter should not be used when e the interference changes rapidly The filter takes about 1 second to adapt to the present level If interference is present and then is suddenly removed interference in the filtered signal will temporarily be increased e your signal contains repetitive components at frequencies close to the mains frequen
13. stage consists of a low drift instrumentation amplifier with programmable gain fully software controlled The gain of this stage is combined with the gain of the recording unit to give a total gain of up to 50 000 at this amplification 200 uV is full scale From the input amplifier the signal is passed to a fixed fifth order low pass filter The filter allows a range of cutoff frequencies to be selected under software control The excitation voltage output circuit is a complementary output stage derived from a stable internal voltage reference capable of giving up to 10 volts 20 volts DC excitation The excitation voltage for each channel is completely independent from other channels The transducer excitation voltage can be adjusted by connecting a resistor between two pins on the plug that plugs into the Bridge Amp s input socket This resistor is usually placed inside the transducer s DIN plug so that the transducer will always get the correct excitation voltage when it is connected To remove any offsets caused by an attached transducer or signal baseline a DC offset circuit with a 16 bit DAC digital to analog converter This is internally connected to the input stage Transducer offsets are zeroed by applying a corrective DC voltage to the input stage via the DAC under software control The DAC is only capable of producing corrective voltages in discrete steps HM Appendix A Technical Aspects Artisan Technology Gr
14. C bus are screwed in firmly and the BNC cables have firm connections Loose connectors can cause erratic front end behavior or may cause the front end to fail to work at all BNC cables can lie under the front end to keep them out of the way Bridge Amp Owner s Guide E Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Figure 2 1 Front end IC input Front end signal output BNC connector cable Connecting a front end to the PowerLab a PowerLab has only one I C output and each front end has one ae I C output and one IC input US C connector cable PowerLab IC output Multiple Front ends Multiple front ends can be connected up to a PowerLab The number that can be connected depends on the number of inputs on the PowerLab The initial front end should be connected as shown in Figure 2 1 The remainder are daisy chained via C cables connecting the IC output of the last connected front end to the C input of the next front end to be added as shown in Figure 2 2 The BNC cable for each front end is connected to one of the inputs of the PowerLab except where otherwise specified Figure 2 2 Connecting multiple front ends to the PowerLab two single front ends shown for simplicity Front end IC inputs PowerLab IC output Front end IC output Bl Chapter 2 Setting Up Artisan Technolog
15. Instruments representative for further assistance B Chapter 3 Adapting Transducers Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Introduction Conventional amplifiers usually have controls on the front to adjust for the connected transducer this means making adjustments each time you change transducers or amplifiers Front ends controlled by ADInstruments software are designed to be easily transferred between recording units and to be quick to disconnect and reconnect so it makes more sense to adapt the transducer The change needs only be done once for any third party transducer which can then be used with any Bridge Amp with the same connector Once set up multiple transducers will work with the same Bridge Amp without needing further adjustment and one can simply change connected transducers as required Some soldering of components is required to adapt third party transducers for use with your Bridge Amp If you have little experience with electronics and no technician to assist you your ADInstruments representative should be able to help Types of Bridge Amp and Adaptation The ML118 Quad and ML119 Octal Bridge Amps have a fixed excitation voltage of 8 V 4 V with respect to ground You cannot adjust the offset voltage range of the zeroing circuit for these front ends Adapting powered transducers for them is relatively simple Transducer Adaptations
16. anteed 888 88 SOURCE www artisantg com APPENDIX Technical Aspects This appendix describes some of the important technical aspects of the Bridge Amp to give some insight into how it works You do not need to know the material here to use the Bridge Amp It is likely to be of special interest to the technically minded indicating what the Bridge Amp can and cannot do and its suitability for particular applications You should not use it as a service manual user modification of the equipment voids your rights under warranty HM Appendix A Technical Aspects Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Bridge Amp Operation The Bridge Amp and other ADInstruments front ends have been designed to integrate fully with the PowerLab system The Bridge Amp is essentially an extension of the PowerLab s input amplifiers so the amplification and hence the ranges offered in LabChart and Scope are the combination of both pieces of hardware The Bridge Amp provides e the additional amplification necessary to deal with the low signal outputs of most transducers e additional programmable filtering to remove unwanted signal frequencies e astable DC excitation voltage supply for powering the transducer e digitally controlled transducer zeroing circuitry Figure A 1 Block diagram of the ML221 Bridge Amp The Mad
17. are supplied with a 3 lead or 5 lead Bio Amp subject cable and lead wire system The ML138 Octal Bio Amp is supplied with unshielded lead wires 1 8 m Bio Amps are only safe for human connection if used with the supplied subject cable and lead wires e All Bio Amp front ends and PowerLab units with a built in Bio Amp are not defibrillator protected Using the Bio Amp to record signals during defibrillator discharges may damage the input stages of the amplifiers This may result in a safety hazard e Never use damaged Bio Amp cables or leads Damaged cables and leads must always be replaced before any connection to humans is made Isolated Stimulator Safety Instructions The Isolated Stimulator outputs of a front end signal conditioner or PowerLab with a built in isolated stimulator are electrically isolated However they can produce pulses of up to 100 V at up to 20 mA Injury can still occur from careless use of these devices Several points must be observed for safe operation of the Isolated Stimulator e The Isolated Stimulator output must only be used with the supplied bar stimulus electrode e The Isolated Stimulator output must not be used with individual physically separate stimulating electrodes e Stimulation must not be applied across the chest or head e Do not hold one electrode in each hand e Always use a suitable electrode cream or gel and proper skin preparation to ensure a low impedance electrode contact Using ele
18. cer is plugged into the Bridge Amp Table 371 Excitation voltage Excitation Excitation voltage sxatatan Transducer excitation DC volts resistance DC volts resistance Q voltage and resistance Q Short circuit 12k 47 k 100 k 150 k 220 k 330 k To program the excitation voltage for a particular transducer choose a value of resistance from Table 3 1 to match the required excitation voltage for your transducer In most cases you should be able to get close to the required excitation voltage by selecting one of those values We recommend that the excitation resistor be 0 25 or 0 125 Watt 2 or 1 metal film Larger resistors may not fit in the confined space of the transducer s DIN plug In general the output voltage from the transducer is directly proportional to the excitation voltage placed across it The greater the excitation voltage the more sensitive the transducer becomes E Chapter 3 Adapting Transducers Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Figure 3 1 Installing the programming resistor the pins are labeled on the plug However transducers have a limit to the level of excitation voltage that can be applied before they are damaged Some resistive elements may start to heat at high excitation voltages causing their resistance to change This degrades the accuracy of the transducer High voltages may also damage capac
19. chnology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Bridge Amp Owner s Guide E However because transducers vary in sensitivity and suitability you should read the following sections before connecting a transducer to a Bridge Amp Compatibility Transducers which operate with the ML110 ML112 ML118 ML119 will operate with the ML22x Bridge Amps The ML110 and ML112 amplifiers had provision for increasing offsetting resolution via an optional resistor installed in the transducer connector Transducers which have this offsetting resistor fitted will operate with the ML22x Bridge Amps without modification Suitable Transducers The Bridge Amps are designed to connect to transducers that require DC excitation voltages such as DC strain gauge or semiconductor transducers If you are uncertain about the suitability of your transducer please provide ADInstruments with an accurate circuit of the transducer and a sample and we will see about testing the device for compatibility Half bridge transducers will need to be wired up with compensating resistors before they can be used with any of the Bridge Amps see Chapter 3 DC Strain gauge These are full bridge or half bridge transducers requiring a DC excitation voltage and output voltages of less than 200 mV full scale They include strain gauge force transducers temperature transducers and pressure transducers Semiconductor These are pow
20. cies e your signal is already free from interference If the signal to noise ratio is greater than about 64 the mains filter introduces more noise than it removes e you are recording at close to maximum sampling rates The mains filter uses some of the PowerLab s processing power and therefore reduces the maximum rate at which you can sample The template is not fully generated until about 1 second after sampling starts and so the mains filter is not fully effective in the first second of each data block Anti alias Click the Anti alias checkbox to turn anti aliasing on and off Aliasing is distortion caused by frequencies of the incoming biological waveform that are more than half the sampling frequency If you monitor physiological signals with a low pass filter setting of 100 Hz but you are only sampling at 100 Hz aliasing may cause the recorded waveform to be quite different from the actual signal An analogy can be seen in older Western films spoked wagon wheels appear to stop or even go backwards when their rate of rotation matches the film frame speed obviously not an accurate record of the wheels motion To prevent aliasing the sampling rate must be at least twice the rate of the highest expected frequency of the incoming waveform For example if monitoring an ECG with maximum frequency components of 100 Hz the sampling rate needs to be at least 200 Hz to provide an accurate signal The sampling rate could be increased
21. ctions respectively each of which has a status indicator light and an overload indicator light E Chapter 1 Overview Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Figure 1 1 The front panels of the Bridge Amps ML221 Bridge Amp Bridge Amp ML224 Quad Bridge Amp r ADINSTRUMENTS 9 3 1 4 Quad Bridge Amp Q R X R ES DN ES DN ES DN ES IN C C C C S x2 S2 IEx2 Status Overload Status Overload Status Overload Status Overload O O O X9 O 0 O O ML228 Octal Bridge Amp ADINSTRUMENTS Octal Bridge Amp YF E E E EE E C Cc C C C C C C Keay Keay Keay SZ SZ Keg SZ SZ Status Overload Status Overload Status Overload Status Overload Status Overload Status Overload Status Overload S Overload O O O O O O 0 O Q O O O O O The Input Socket Transducers are connected to a Bridge Amp using the eight pin DIN sockets on the front panel The sockets provide terminals for supplying a transducer with power and for receiving the transducer output Front ends are supplied with DIN plug kits one per connection to be fitted to those transducers that lack them The connection is discussed in more detail later The Status Indicator The Status indicator of the Bridge Amp is loca
22. ctrodes without electrode cream can result in burns to the skin or discomfort for the subject e Subjects with implantable or external cardiac pacemakers a cardiac condition or a history of epileptic episodes must not be subject to electrical stimulation e Always commence stimulation at the lowest current setting and slowly increase the current e Stop stimulation if the subject experiences pain or discomfort SN Safety Notes Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com e Do not use faulty cables or those that have exhibited intermittent faults e Do not attempt to measure or record the Isolated Stimulator waveform while connected to a subject using a PowerLab input or any other piece of equipment that does not carry the appropriate safety symbol see Safety Symbols above Always check the status indicator on the front panel It will always flash green each time the stimulator delivers a current pulse A yellow flash indicates an out of compliance OOC condition that may be due to the electrode contact drying up Always ensure that there is good electrode contact at all times Electrodes that are left on a subject for some time need to be checked for dry contacts An electrode impedance meter can be used for this task e Always be alert for any adverse physiological effects in the subject At the first sign of a problem stimulation must be stopped either
23. e 20 how they work 20 21 suitable 19 unsuitable 20 U unsuitable transducers 20 user modification 41 using ADInstruments programs 26 33 using this guide 14 V voltmeter 32 Z Zero button 32 zeroing 31 32 automatic 31 manual 31 Bridge Amp Owner s Guide S Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com A rtisan Artisan Technology Group is your source for quality Pee new and certified used pre owned equipment FAST SHIPPING AND SERVICE CENTER REPAIRS WE BUY USED EQUIPMENT DELIVERY Experienced engineers and technicians on staff Sell your excess underutilized and idle used equipment TENS OF THOUSANDS OF at our full service in house repair center We also offer credit for buy backs and trade ins IN STOCK ITEMS www artisantg com WeBuyEquipment A EQUIPMENT DEMOS HUNDREDS OF Instral e REMOTE INSPECTION LOOKING FOR MORE INFORMATION TO qii Remotely inspect equipment before purchasing with Visit us on the web at www artisantg com 7 for more our interactive website at www instraview com 7 information on price quotations drivers technical LEASING MONTHLY specifications manuals and documentation RENTALS ITAR CERTIFIED ee Mus Contact us 888 88 SOURCE sales artisantg com www artisantg com
24. e normal text remains If you were expecting a connected front end and see the normal text instead you should quit the application turn the PowerLab off and check the connections Then restart the PowerLab and the application The documentation for LabChart and Scope does not cover front end specific features These features are described in detail here for LabChart For the most part dialogs for LabChart and Scope should be much the same The Bridge Amp Dialog The Bridge Amp dialog allows software control of the various amplifiers and filters in the Bridge Amp and PowerLab for an input The signal present at a PowerLab input is displayed so that you can see the effects of changes straight away Once the settings in the dialog are changed click OK to apply them To set up many inputs quickly click the arrows at the top of the dialog or use the right or left arrow keys on the keyboard to move to the equivalent dialogs for adjacent inputs This skips channels that have their inputs turned off The input number is shown at the top of the dialog and the channel title if any is shown in the vertical Amplitude axis of the dialog Signal Display The input signal is displayed so you can see the effect of changing the settings no data are in fact recorded when setting things up Slowly changing waveforms will be represented quite accurately whereas quickly changing signals will be displayed as a solid dark area showing only the enve
25. er looking at the DIN plug from the cable side Figure 3 3 The correct length of wiring to the DIN plug Any unused wires from the transducer should be cut and insulated to prevent shorting of signals or damage to the equipment Ground or centre tap shield Signal positive Excitation voltage programming resistor Signal negative Excitation negative Excitation positive The main insulation sheath of the transducer wiring should be clamped with the strain relief device within the plug so that it just clears the excitation voltage resistor The transducer will normally have some sort of cable shield which should be connected to pin 7 of the DIN plug If the casing of the DIN plug is metal it is recommended and good practice to ensure that the casing will also be connected to the shield Wire from transducer Transducer ground earth wire The Finished Transducer After connecting the excitation voltage programming resistor and wiring up the transducer to the DIN plug the transducer should now be fully configured for your application The excitation voltage will be set automatically when you plug the transducer into the Bridge Amp B Chapter 3 Adapting Transducers Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Bridge Amp Owner s Guide S Artisan Technology Group Quality Instrumentation Guar
26. erLab system consists of a recording unit and application programs that run on the computer to which the unit is connected It is an integrated system of hardware and software designed to record display and analyze experimental data Your Bridge Amp is one of a family of front ends meant for use with your PowerLab system Front ends are ancillary devices connected to the PowerLab recording unit to extend the system s capabilities They provide additional signal conditioning and other features and extend the types of experiments that you can conduct and the data you can record AII ADInstruments front ends are designed to be operated under full software control No knobs dials or switches are needed although some may be provided for reasons of convenience or safety Bridge Amp Owner s Guide E Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com The PowerLab controls front ends through an expansion connector called the I C eye squared sea bus Each new front end added to the system connects to the back of the previous front end in a simple daisy chain structure This makes it very easy to add front ends to the system or to transfer them between PowerLabs In general each front end requires one analog input of the PowerLab Note that the Quad Bridge Amp acts as if it were four individual Bridge Amps and the Octal Bridge Amp as if it were eight Front ends are automatically recogn
27. ered transducers typically used for light displacement and temperature measurements giving output voltages less than 200 mV full scale Generally a Bridge Amp can be used with transducers that e require DC excitation voltages not AC e have transducer output voltages less than 5 V full scale e have transducer impedances less than 10 kQ B Chapter 1 Overview Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Unsuitable Transducers Some transducers are not supported and should not be used with the Bridge Amp These include LVDT capacitive bridge piezoelectric and high voltage transducers LVDT linear variable differential transformer This type of transducer requires AC excitation voltages The Bridge Amp is for use with transducers requiring DC excitation Connecting an LVDT transducer to the Bridge Amp may damage the transducer Capacitive Bridge These transducers require AC excitation The Bridge Amp is for use with transducers requiring DC excitation Piezoelectric These transducers are not recommended owing to the relatively low input impedance of the single Bridge Amp piezoelectric transducers typically need amplifiers with input impedances of tens of megohms and their half bridge configuration High voltage Transducers generating more than 5 V full scale will exceed the input range of the Bridge Amp A high voltage powered transducer may require so
28. ff Check to see that all cables are firmly inserted and screwed in Make sure the input is the same channel from which you expect to use the Bridge Amp in the software Ensure no other equipment is attached to the particular channel of the Powerlab from which you expect to see the Bridge Amp Start up again to see if this has fixed the problem You are using an early version of LabChart or Scope e Upgrade to the latest version of the software Contact your ADInstruments representative for information The BNC or IC cable is faulty e Replace the cable and try again Immediately label all cables proved faulty so that you don t use them again by accident The Bridge Amp is faulty e This is the least likely event If the Bridge Amp will not work properly after the previous measures then try using it on another PowerLab If the Bridge Amp s Status indicator fails to light with a second PowerLab the Bridge Amp may be faulty Contact your ADInstruments representative to arrange for repairs One or more overload indicators glow amber If a light glows amber yellow it indicates some fault such as a short circuit a badly wired bridge transducer or an excitation overload e Check to see that all transducer connections are firm e Check for short circuits and badly wired bridge transducers by changing them around connecting new ones and so on e Check transducer impedances In particular a low impedance Grass transducer 250 Q
29. from the software or by flicking down the safety switch on the front panel of any built in Isolated Stimulator or the ML180 Stimulus Isolator e The ML180 Stimulus Isolator is supplied with a special transformer plug pack The plug pack complies with medical safety requirements Therefore under no circumstances should any other transformer be used with the Stimulus Isolator For a replacement transformer plug pack please contact your nearest ADInstruments representative General Safety Instructions To achieve the optimal degree of subject and operator safety consideration should be given to the following guidelines when setting up a PowerLab system either as stand alone equipment or when using PowerLab equipment in conjunction with other equipment Failure to do so may compromise the inherent safety measures designed into PowerLab equipment The following guidelines are based on principles outlined in the international safety standard IEC60601 1 1 General requirements for safety Collateral standard Safety requirements for medical systems Reference to this standard is required when setting up a system for human connection Bridge Amp Owner s Guide B Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com PowerLab systems and many other devices require the connection of a personal computer for operation This personal computer should be certified as complying with IEC60950 a
30. g The transducer is defective or subject to excessive load causing the offset range of the Bridge Amp s zeroing circuitry to be exceeded e Check the transducer with another Bridge Amp if possible and try again Contact the supplier or manufacturer of the transducer if there still seems to be a problem You are using an unmodified half bridge transducer e Half bridge transducers may require rewiring with compensating resistors before they can be used with Bridge Amps HM Appendix B Troubleshooting Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com The signal from the transducer is noisy at lower ranges This is usually the amplified noise from the transducer and its associated circuitry not a fault as such e Set the low pass filter to remove the noise The signal from the transducer is weak even at lower ranges The connection to the transducer may be connected incorrectly or may be loose or disconnected Adaptations within the plug may be faulty or badly wired up e Check the connection and try again If the transducer has been adapted for use with the Bridge Amp check the wiring and soldering within the plug e Ensure that the particular channel in LabChart has been correctly recognized as a Bridge Amp and not as Input Amplifier The transducer itself is faulty e Check the transducer with another Bridge Amp if possible and try again Contact the sup
31. ic features and looks at which transducers can be used with them E Chapter 1 Overview Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com How to Use This Guide This owner s guide describes how to set up and begin using your Bridge Amp The chapters give an overview of front ends in general and the Bridge Amp in particular and discuss how to connect the hardware perform a simple power up test and use the Bridge Amp with some ADInstruments programs The appendices provide technical information about the front ends and take a look at some potential problems and their solutions At the end of this guide you ll find an index Technical terms that are not defined in the glossary of terms included with the owner s guide for your PowerLab are defined as they appear Checking the Front end Before connecting the Bridge Amp to anything check it carefully for signs of physical damage 1 Check that there are no obvious signs of damage to the outside of the front end casing 2 Check that there is no obvious sign of internal damage such as rattling Pick up the front end tilt it gently from side to side and listen for anything that appears to be loose If you have found a problem contact your authorized ADInstruments representative immediately and describe the problem Arrangements can be made to replace or repair the front end Front end Fundamentals The Pow
32. itive bridge transducer elements To avoid problems the excitation voltage should be set according to the manufacturer s recommendation for that transducer To set the excitation voltage for a transducer you will need to solder the chosen resistor between pins 5 and 8 of the eight pin DIN plug as shown in Figure 3 1 Mount the resistor as shown for maximum clearance within the plug Excitation voltage programming resistor Wiring Up the Transducer The second step in preparing a powered transducer for use with the Bridge Amp is to wire the transducer to the DIN plug There are several things to note when wiring up transducers 1 Make sure that the transducer wiring passes through the casing before soldering the wires to the plug 2 The transducer wires should be cut stripped and tinned prior to soldering to ensure a good connection 3 The pin numbers shown in the diagrams are the numbers marked on most standard DIN plugs If the plug has no numbers or different ones go by the layout shown here Wiring Up a Full Bridge Transducer This procedure should be used to wire full bridge transducers only not half bridge transducers The transducer lead wires should be soldered to the pins of the DIN plug as shown in Figure 3 2 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Bridge Amp Owner s Guide E Figure 3 2 The wiring connections for a full bridge transduc
33. ized by the PowerLab system Any front end feature such as gain or filtering is combined with the appropriate features of the software and presented as a single set of software controls This seamless integration of front ends greatly increases the flexibility and ease of use of the PowerLab system The Front end The Bridge Amp is designed to allow the PowerLab to connect to most DC bridge transducers including commonly available force transducers temperature probes light meters displacement transducers pressure transducers and similar devices There are several models of Bridge Amp The Bridge Amp provides just one connection for a bridge transducer the Quad Bridge Amp provides four connections for bridge transducers and the Octal Bridge Amp provides eight connections for bridge transducers Grass transducers can connect to any ADInstruments Bridge Amp using a Grass adapter cable available from ADInstruments Use the MLAC11 Grass Adapter Cable to connect a Grass transducer to the ML221 ML224 or ML228 Bridge Amp The rest of this chapter contains general information about the features connections and indicators of the Bridge Amps More detailed information can be found in the technical appendices The Front Panel The front panel of a Bridge Amp has a single socket for a transducer connection a status indicator light and an overload indicator light The front panel of a Quad or Octal Bridge Amp has four or eight transducer conne
34. k check can be performed on the Bridge Amp To perform the self test 1 Turn on the PowerLab and check that it is working properly as described in the owner s guide that was supplied with it 2 Once the PowerLab is ready open the ADInstruments program such as LabChart or Scope 3 While it starts up keep a close eye on the Status and Overload indicators on the Bridge Amp During initialization the Status indicators glow green flash briefly and then remain lit If the indicator glows green the Bridge Amp is working properly and you can quit the application If a light does not go on when the program is started this indicates either that the front end is not connected properly or that there is a software or hardware problem Bridge Amp Owner s Guide E Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com If the overload light glows yellow or amber on any Bridge Amp this indicates some fault such as a short circuit a badly wired bridge transducer or an excitation overload In the first instance check your cable connections and transducers and repeat the self test If this does not solve the problem contact your ADInstruments representative When a Bridge Amp is properly connected to the PowerLab the Input Amplifier menu command are replaced by Bridge Amp for the input channel to which it is connected If the application fails to find a front end connected th
35. k of damage to the transducer Check the transducer wiring carefully before re attaching the transducer If the fault persists refer to the Troubleshooting section of this Owner s Guide For the overload indicator to function power must be applied to the Bridge Amp via a PowerLab LabChart software does not need to be loaded When a software application is running and a channel is being zeroed the Status indicators for the other channels should temporarily be off The Back Panel The back panel of the Bridge Amp provides all the sockets required to connect the Bridge Amp to the PowerLab and to other front ends I C Input and Output Sockets Two nine pin sockets are used to communicate with the PowerLab they are marked I C Bus a bus is simply information transmission circuitry such as cables and connectors These sockets allow multiple front ends to be used independently with one PowerLab Power and control signals to the front ends come from the PowerLab Many front ends can be connected to the system in series output to input providing there is the same number of channel inputs available on the PowerLab this is discussed in more detail in the next chapter B Chapter 1 Overview Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Figure 1 2 The back panels of the Bridge Amps ML221 Bridge Amp Z Signal Output
36. left and Macintosh right k Zero Manual Zeroing The up and down arrows near the Zero button allow manual adjustment of the signal offset Click the up arrow to shift the signal positively and the down arrow to shift it negatively The shift by clicking the arrow buttons depends on the range setting At high ranges the increments are larger to adjust the offset efficiently Automatic Zeroing To perform automatic zeroing click Zero the program works out a corrective DC voltage that cancels as closely as possible the output voltage from the transducer Auto zeroing may take about 20 seconds to work out the best zeroing value at all ranges A dialog with a progress bar appears click the Cancel button or type Command period to stop the zeroing process If there is still offset after auto zeroing then Option click the up and down arrow buttons to adjust the zeroing slightly by the smallest increment at any range Bl Chapter 2 Setting Up Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Note Variations in the transducer signal during the auto zeroing operation will cause the software to fail to zero the offset properly if it zeroes at all Make sure that the transducer is kept still and that no varying signal is applied during the operation The offset display a small numeric indicator above the Zero button shows the corrective voltage used to adjust for transducer
37. lick the Scroll button to start scrolling again Shift and stretch the vertical Amplitude axis by clicking and dragging it in various ways to make the best use of the available display area It functions the same as the Amplitude axis of the Chart window controls are identical and any change is applied to the Chart Window On a Macintosh Show Range Axis in the Scale pop up menu displays m 2 ry the range axis at the right of the display area and the Compression buttons adjust the horizontal axis of the data display area Setting the Range Range The Range pop up menu lets you select the input range or sensitivity of the channel combined range of the PowerLab and Bridge Amp Changing the range in the Bridge Amp dialog is equivalent to changing it in the Chart window The default setting is 5 V and the ranges go down to 200 uV in 14 steps Filtering The filtering options provided are appropriate to the type of transducers used with the Bridge Amp and the signals usually measured which tend to be of lower frequency Low pass filters allow you to remove high frequency components such as noise from an input signal The Mains filter allows you to remove interference at the mains frequency typically 50 or 60 Hz Low Pass Filtering The Low Pass pop up menu provides a choice of filters to remove high frequency components from the signal They are 1 2 10 20 100 and 200 Hz and 1 kHz The highest frequency you can actually
38. lope shape of the signal formed by the minimum and maximum recorded values The average signal value is shown at the top left of the display area Bl Chapter 2 Setting Up Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Figure 2 3 The Bridge Amp dialog for Windows before zeroing Figure 2 4 The Bridge Amp dialog for Macintosh after zeroing Pause Scroll buttons Input selection Average signal value Bridge Amp Range pop up Set the offset for the Bridge Amp Mains filter Displays the Displays a voltmeter on screen for use Units Conversion dialog when setting the offset externally Input selection Average signal value Bridge Amp Input 1 Bridge Amp Range 5V HJ 0 00000 V Range pop up 4 Low Pass Off HJ Offset 0 43 0 Set the offset for the Bridge Amp 8 C Mains Filter Mains filter f Invert v Anti alias C Pause Scroll button Displays a voltmeter on screen for use when setting the offset externally Displays the Units Conversion dialog Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Bridge Amp Owner s Guide B You can stop the signal scrolling by clicking the Pause button at the bottom left Macintosh or top right Windows of the data display m lt area On the Macintosh this changes to the Scroll button C
39. me signal attenuation How Transducers Work The Bridge Amp can connect to most bridge type transducers hence its name The term bridge refers to the circuit configuration that is normally called a Wheatstone bridge These transducers come in two forms full bridge and half bridge Some explanation is given here of bridge type transducers although there are of course other types that work differently such as the semiconductor transducer The full bridge circuit is fairly versatile in that the circuit elements shown as the rectangular boxes in Figure 1 3 can be resistive capacitive or thermal circuit elements allowing the bridge to measure force pressure temperature and so forth This circuit produces an electrical output in proportion to an appropriate stimulus applied to one or more of the four elements Because of the balancing effect of the four elements high precision is possible Full bridge transducers should work without problems A half bridge transducer only uses half of the full bridge circuit It consists of two elements of equal value with an excitation voltage applied across them The output of the transducer is taken at the junction of the two elements Bridge Amp Owner s Guide S Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Figure 1 3 positive excitation positive excitation Left a full bridge transducer right a half bridge transducer
40. nd should be located outside a 1 8 m radius from the subject so that the subject cannot touch it while connected to the system Within this 1 8 m radius only equipment complying with IEC60601 1 should be present Connecting a system in this way obviates the provision of additional safety measures and the measurement of leakage currents Accompanying documents for each piece of equipment in the system should be thoroughly examined prior to connection of the system While it is not possible to cover all arrangements of equipment in a system some general guidelines for safe use of the equipment are presented below Any electrical equipment which is located within the SUBJECT AREA should be approved to IEC60601 1 Only connect those parts of equipment that are marked as an APPLIED PART to the subject APPLIED PARTS may be recognized by the BF or CF symbols which appear in the Safety Symbols section of these Safety Notes Only CF rated APPLIED PARTS must be used for direct cardiac connection Never connect parts which are marked as an APPLIED PART to those which are not marked as APPLIED PARTS Do not touch the subject to which the PowerLab or its peripherals is connected at the same time as making contact with parts of the PowerLab or its peripherals that are not intended for contact to the subject Cleaning and sterilization of equipment should be performed in accordance with manufacturer s instructions The isolation barrier ma
41. ng 45 PODI s oo Bee ee ee eee ee eee em ue ee ee oe 46 C Specifications 49 Single Quad and Octal Bridge Amps ML221 ML224 amp ML228 49 Index 51 Bridge Amp Owner s Guide B Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Safety Notes Statement of Intended Use All products manufactured by ADInstruments are intended for use in teaching and research applications and environments only ADInstruments products are NOT intended to be used as medical devices or in medical environments That is no product supplied by ADInstruments is intended to be used to diagnose treat or monitor a subject Furthermore no product is intended for the prevention curing or alleviation of disease injury or handicap Where a product meets IEC 60601 1 it is under the principle that e itis amore rigorous standard than other standards that could be chosen and e it provides a high safety level for subjects and operators The choice to meet IEC 60601 1 is in no way to be interpreted to mean that a product e isa medical device e may be interpreted as a medical device or e is safe to be used as a medical device SN Safety Notes Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Safety Symbols Devices manufactured by ADInstruments that are designed for direct connection to humans are tested to IEC 601 1 1998
42. on dialog with which you specify the units for the channel and using waveform measurements calibrate the channel The waveform in the data display area of the Bridge Amp dialog is transferred to the data display area of the Units Conversion dialog Use the Pause button to capture a specific signal The units conversion only applies to subsequently recorded signals so it is more limited than choosing Units Conversion from a Channel Function pop up menu as it does not allow conversion of individual blocks or pages of data Bl Chapter 2 Setting Up Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Bridge Amp Owner s Guide S Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com C HAPTER Adapting Transducers This chapter describes the modifications that may be required to connect third party transducers to the Bridge Amp Transducers supplied by ADInstruments should connect directly without modification so if using those you need not read this chapter If you are using powered third party transducers with your Bridge Amp you may need to adapt them using the information provided here NOTE Please ensure that any modifications made to transducers are carried out by experienced technical staff as incorrect wiring may damage the transducer or Bridge Amp If you are unsure please contact your nearest AD
43. or so may suffer overload if the excitation is too high Bridge Amp Owner s Guide S Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com On starting up the software an alert indicates that there is a problem with the front end or driver The correct Bridge driver is not installed on your computer it should be in the Essential Files folder inside the LabChart or Scope folder e Reinstall the software You are using an early version of LabChart or Scope e Upgrade to the latest version of the software Contact your ADInstruments representative for information The BNC or IC cable is faulty e Replace the cable and try again Immediately label all cables proved faulty so that you don t use them again by accident The Bridge Amp is faulty e This is the least likely event If the Bridge Amp will not work properly after the previous measures then try using it on another PowerLab If the Bridge Amp s Status indicator fails to light with a second PowerLab the Bridge Amp may be faulty Contact your ADInstruments representative to arrange for repairs The trace will not zero properly when using the automatic or manual zeroing controls Variations in the transducer signal during auto zeroing may cause the software to fail to zero the offset properly if it zeroes at all e Make sure that the transducer is kept still and that no varying signal is applied during auto zeroin
44. oup Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Bridge Amp Owner s Guide S Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com APPENDIX mp Troubleshooting This appendix describes most of the common problems that can occur when using the Bridge Amp with your PowerLab recording unit It covers how these problems are caused and what you can do to alleviate them If the solutions here do not work earlier chapters the LabChart Help Center and the guide to your PowerLab may contain possible solutions If none of the solutions here or elsewhere are of help then consult your ADInstruments representative Most of the problems that users encounter are connection problems and can usually be fixed by checking connections and starting up the hardware and software again Very rarely will there be an actual problem with the Bridge Amp or the PowerLab itself B Appendix B Troubleshooting Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Problems The Status indicator fails to light when the software is started or the Bridge Amp command does not appear where it should The C cable or one or more BNC to BNC cables from the Bridge Amp to the PowerLab are not connected have been connected incorrectly to the wrong input for instance or are loose e Turn everything o
45. plier or manufacturer of the transducer if there still seems to be a problem The signal from the transducer drifts excessively e Both the Bridge Amp and transducer require time to reach thermal equilibrium Allow 5 minutes of warm up time with the transducer connected and then try to re zero the transducer e The transducer itself may be of low quality e The excitation voltage may be too high and causing the transducer to self heat and drift Try reducing the excitation voltage Bridge Amp Owner s Guide S Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com APPENDIX B Specifications Single Quad and Octal Bridge Amps ML221 ML224 amp ML228 Input Number of inputs 1 single 4 Quad or 8 Octal 8 pin DIN Input configuration Differential Amplification range 200 uV to 5 V full scale in 14 steps combined PowerLab and Bridge Amp 5 V 2 V oh Ve 500 mV 200 mV 100 mV 50 mV 20 mV 10 mV 5mV 2mV 1 my 500 uV 200 uV Amplification accuracy 0 5 combined PowerLab and Bridge Amp Maximum input voltage 10 volts Input impedance 2 x 1 MQ single ended 2 MQ differential Low pass filtering 1 Hz to 1 kHz in seven steps software selectable HM Appendix C Specifications Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com CMRR differential Input
46. ranteed 888 88 SOURCE www artisantg com Bridge Amp Owner s Guide E A adapting transducers 35 39 ADInstruments programs 26 33 aliasing 30 analog output 18 automatic zeroing 31 B back panel 17 18 block diagram 42 Bridge Amp models 15 bridge amp software 27 33 C checking the front end 14 checking transducers 21 cleaning 10 connections multiple front ends 25 single front end 24 to the PowerLab 24 25 D digital to analog converter 43 DIN socket 16 display offset 32 E excitation overload 17 excitation voltage 36 37 38 Index F filtering 29 front panel 15 17 front end driver 26 47 front ends general 14 15 full bridge transducers 20 38 39 H half bridge transducers 20 how transducers work 20 21 I impedances maximum 19 input socket 16 I2C bus 15 17 43 L LabChart 26 M maintenance 10 manual zeroing 31 O offset adjustment 31 32 offset display 32 overload indicator 17 P PowerLab system 14 S3 Index Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com S Safety Notes 5 11 Scope 26 self test 26 Status indicator 16 storage 10 suitable transducers 19 T technical specifications 49 50 transducer capacitive bridge 20 DC strain gauge 19 high voltage 20 LVDT 20 piezoelectric 20 semiconductor 19 transducers adapting 35 39 checking 21 DIN 36 39 full bridge 20 38 39 Grass 22 half bridg
47. s aa 3 rrap pee a ee eae ee 14 The Front end 24 204 Rt eHow om Eee eRe eee Eee Ds 15 The Front Panel 25 eae poe ee agen Gee ee eee Ond ass 15 The Dack Panel ea 2 aeea e women a a a a e E Ps 17 sie IUC ee ea raene ee Ree oe Ge 18 COMPAD eos 4 de ee oe oe ee oec dim eee Gee abe E d 19 olabi Trans d UOS S 4 a4 Gere hun S 99 39 X 6 ee ae Oe ee S 19 staal M Transducers c r 20 How Iransducers Work auos Sos ww Go bases tg RS Nue 20 Checking the Transducer llle 21 2 Setting Up 23 PoworLap Requirements uv a d ves Eua uer oO ee RN AME ee m ERU d 24 Software ReguiremelS 4299399 3499 Dee ewe ESE OH GSS 24 Connecting to the PowerLab aac up e eee eee sms Puede E 24 Multiple Frontends u s onwvb sew sade 99 9939 3292 5 33 25 Using ADInstruments Progra adage Sox to ees EO Ste p oe ee d 26 The Bridge Amp Dialog amp 52223555 5 9352394 32 5954 2r 3 Adapting Transducers 35 ITHOCUCHONG bet e ce eee teen ae eben ee iger ea ee ee amp oop oe 36 Transducer AdaptahonS as e s dee eto ee 9 wo he eee er eee ed oa ee 36 Setting the Excitation Voltage lees 37 Witing Up the Transd cer c s sque RO eee eae eae Ses 38 A Technical Aspects 41 POPE Amp Operations s x 92s Gee aba eo Ru eee eS 393 9 3 42 Technical Descriptions ana s s so asa g ai en dae ene on ose tones d 43 SN Contents El Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com B Troubleshooti
48. s of ADInstruments PowerLab LabTutor and MacLab are registered trademarks of ADInstruments Pty Ltd The names of specific recording units such as PowerLab 8 30 are trademarks of ADInstruments Pty Ltd LabChart Chart and Scope application programs are trademarks of ADInstruments Pty Ltd Other Trademarks Apple Mac and Macintosh are registered trademarks of Apple Computer Inc Windows Windows XP and Windows Vista are either registered trademarks or trademarks of Microsoft Corporation All other trademarks are the property of their respective owners Product ML221 Bridge Amp ML224 Quad Bridge Amp ML228 Octal Bridge Amp Document Number U ML221 OG 002B Part Number 4708 Copyright O February 2008 ADInstruments Pty Ltd Unit 13 22 Lexington Drive Bella Vista NSW 2153 Australia All rights reserved No part of this document may be reproduced by any means without the prior written permission of ADInstruments Pty Ltd Web www adinstruments com Technical Support support au adinstruments com Documentation documentation adinstruments com ADInstruments Pty Ltd ISO 9001 2000 Certified Quality Management System Reg No 1053 Erg Bridge Amp Owner s Guide E Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Contents Safety Notes 5 1 Overview 13 How to Use This Guide sa mo redona ma Ln 14 Checking the Front end aa aaa e 14 Frontend Fundamental
49. ted at the bottom right of the front panel and the Status indicators of the Quad Bridge Amp and Octal Bridge Amp are located beneath each connector on the front panel When an ADInstruments program such as LabChart starts up the Status indicator light should glow green indicating that the program has found the front end checked and selected it and is ready to use it If the light does not glow when the program is running this indicates either that the front end is not connected properly or that there is a software or hardware problem Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Bridge Amp Owner s Guide E The Overload Indicator The Overload indicator is located on the left side of the front panel of the Bridge Amp and to the right of the Status indicator on the Quad and Octal Bridge Amps The Overload indicator is normally off If the indicator lights when a transducer is attached it indicates an out of compliance condition meaning that the excitation voltage drops because too much current is being drawn by the load When the Bridge Amp detects a problem with the transducer for instance a wiring fault with a transducer causing a short circuit the overload indicator will glow yellow or amber and will remain on until the fault is rectified If the overload indicator remains on with a transducer attached the transducer should be removed immediately to minimize the ris
50. traints e They shall not be placed on the floor e Additional multiple portable socket outlets or extension cords shall not be connected to the system e They shall only be used for supplying power to equipment which is intended to form part of the system Cleaning and Sterilization ADInstruments products may be wiped down with a lint free cloth moistened with industrial methylated spirit Refer to the manufacturer s guidelines or the Data Card supplied with transducers and accessories for specific cleaning and sterilizing instructions Preventative Inspection and Maintenance PowerLab systems and ADInstruments front ends are all maintenance free and do not require periodic calibration or adjustment to ensure safe operation Internal diagnostic software performs system checks during power up and will report errors if a significant problem is found There is no need to open the instrument for inspection or maintenance and doing so within the warranty period will void the warranty Bridge Amp Owner s Guide B Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Your PowerLab system can be periodically checked for basic safety by using an appropriate safety testing device Tests such as earth leakage earth bond insulation resistance subject leakage and auxiliary currents and power cable integrity can all be performed on the PowerLab system without having to remove the covers
51. ue a ML224 and 228 Bridge plug ze Amps are similar but with four or eight inputs gH 2 On Transducer Nim Signal respectively signal inputs O A lowpass Output filter Overload indicator 2 IC i O __ Bridge lC Output Excitation atiati DAC control voltage s A aa interface Excitation voltage O V of power PC setting resistor O supply Input Online indicator Bridge Amp Owner s Guide S Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Technical Description The PowerLab provides control and low voltage power to front ends through a special expansion connector called the C eye squared sea bus Front ends are also connected to the analog inputs of the recording unit via a BNC to BNC cable The overall operation of the Bridge Amps can be better understood by referring to Figure A 1 The digital control interface used to control filter settings gain coupling and zeroing circuits uses an I C interface system which provides a 4 wire serial communication bus to the recording unit and other front ends All control of the Bridge Amp is through this bus Also present on the I C connector is a set of power supply rails derived from the recording unit The Bridge Amp has its own on board regulators to ensure a stable power supply The input
52. y Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com Using ADInstruments Programs Front ends are used with PowerLabs and ADInstruments software applications such as LabChart and Scope see Software Requirements p 24 The Bridge Amp s amplification and filtering is combined with that of the PowerLab and the program and presented as a single set of software controls in this case replacing the Input Amplifier dialog with the Bridge Amp dialog The LabChart Help Center and Scope User s Guide detail the Input Amplifier dialog and explain relevant terms and concepts The Front end Driver A driver is a piece of software the computer uses to drive a peripheral device In order for a front end to be recognized by ADInstruments applications the appropriate front end driver must be present The Bridge front end driver is used with the Bridge Amp Front end drivers are installed when ADInstruments applications are installed on the computer LabChart and Scope for Macintosh keep separate drivers in the Essential Files folder in the LabChart or Scope folder LabChart for Windows has them built in and Scope for Windows has them in the Essential Files folder in the Scope folder To replace the drivers you generally need to reinstall the ADInstruments software The Bridge Amp Self test Once the Bridge Amp is properly connected to the PowerLab and when the proper software is installed on the computer a quic
53. y be compromised if manufacturer s cleaning instructions are not followed The ambient environment such as the temperature and relative humidity of the system should be kept within the manufacturer s specified range or the isolation barrier may be compromised The entry of liquids into equipment may also compromise the isolation barrier If spillage occurs the manufacturer of the affected equipment should be contacted before using the equipment BN Safety Notes Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com e Many electrical systems particularly those in metal enclosures depend upon the presence of a protective earth for electrical safety This is generally provided from the power outlet through a power cord but may also be supplied as a dedicated safety earth conductor Power cords should never be modified so as to remove the earth connection The integrity of the protective earth connection between each piece of equipment and the protective earth should be verified regularly by qualified personnel e Avoid using multiple portable socket outlets such as power boards where possible as they provide an inherently less safe environment with respect to electrical hazards Individual connection of each piece of equipment to fixed mains socket outlets is the preferred means of connection If multiple portable socket outlets are used they are subject to the following cons

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