DC Signal Conditioner manual
Contents
1. k k k k AA Www 1 1 Qn E oak ROP GO M PAGE 2 2 2 3 1 1 Introduction 1 1 1 Universal Amplifier Model 13 4615 58 The performance of the Harvard Universal Amplifier shown in Figure 1 1 truly lives up to its name uni versal The unit acts as an excellent differential amplifier or provides the capabilities of a top grade biophysical amplifier when utilized along with an Isolated Preamplifier Model 11 5407 58 High input impedance wide bandwidth low noise low drift and transducer excitation are all incorporated to pro duce the finest signal conditioning available in any single amplifier module 1 1 2 Isolated Preamplifier Model 13 5407 58 Harvard s Isolated Preamplifier shown in Figure 1 2 enhances the performance of the Universal Amplifier by providing signal isolation between the signal source and the measuring equipment Since the Isolated Preamplifier is intended to be physically placed near the signal source the small biophysi cal signals are conditioned before they can be degraded by noise pickup or the capacitance of long sig nal cables The Isolated Preamplifier was designed solely for use with the Universal Amplifier Isolated Preamp cH DC mu zero 1 1 3 Defibrillator Protector Model 11 5407 59 The Harvard Plug in Defibrillator Protector is shown in Figure 1 3 This unit provides input pro tection for the Is2. the input lines are opened and all three leads are shorted together to produce a zero base line the zero on switch should also be depressed during the connection of the input signal source See Section 3 4 3B 4 3 2 INPUT PROTECTION Back to back diodes are connected to each of the signal input lines to provide protection against exces sive inputs up to 40 volts RMS Once a input signal surpasses 15 volts the clipping diodes will be turned on and limit the signal strength 4 3 3 INPUT AMP The input amp consist of fully floating differential FET stages a X20 gain amplifier for each signal and a summing amplifier The FET circuits provide low noise while the gain amplifiers permit balancing of signals and adjustment of gain After the signals are summed the output of the input amp is sent to the isolation amplifier O0ASL O0ASL ei d3 1V10SI NON OGASI OSI 1 NOILOALOWd LAdNI 00 0 2 yo MS 900 J 4 3 4 ISOLATION AMPLIFIER The purpose of the isolation amplifier is to provide electrical isolation between the input and output of the Isolated Preamplifier This is accomplished by modulating the input passing it through a trans former and then demodulating the signal This stage also isolates the and 15VDC and common lines coming from the Universal Amplif
3. 57 with a Universal Amplifier is shown schematically in Figure 2 4 Polarizing Key E PIN FUNCTION NEC NEC NEC NEC NEC 15VDC SHUNT CAL 15VDC EXC gt EXC oe O a 10 SHIELD 11 SIG 12 SIG 66 2 5 Isolated Preamplifier Installation The Isolated Preamplifier Model 11 5407 58 is a mobile unit which should be located as near the patient as possible without exceeding the interconnect cable length of fifteen 15 feet The Deutsch connector on the Isolated Preamplifier cable is installed by aligning the blue line on the locking ring on the cable connector with the polarizing key on the amplifier connector See Figure 2 1 Push the cable connector in until the locking ring snaps into place and or the orange ring behind the locking ring on the connector shell becomes visible Note the caution in Section 2 3 regarding the connector installation CARD EDGE SPADE LUG PUSH LUG PIN NO TERMINALS TERMINALS FUNCTION 1 PWR COM 2 9 1 REC OUT a 3 15VDC 5 4 15VDC 5 8 SIG COM 6 6 13 NEC 5 7 NEC Tg NEC A 12 6 NEC B 11 5 MON OUT w C 10 7 REMOTE RESET 5 D 1 8 RESET COM a E 2 9 NEC S F 3 10 NEC H 4 11 NEC lT 5 12 SCALED OUT DIFFERENTIAL MEASUREMENT SOURCE UNIVERSAL AMPLIFIER SINGLE ENDED MEASUREMENT SOURCE S TRANSDUCER E SHUNT CAL RESISTOR VV
4. a personal injury hazard not immediately accessible as one reads the marking or a hazard to property including the equipment itself DANGER indicates a personal injury hazard immediately accessible as one reads the marking Symbols as Marked on Equipment DANGER High Voltage Protective ground earth terminal 1 ATTENTION Refer to manual SAFETY SUMMARY Continued Power Source This instrument is intended to operate from a power source that does not apply more than 250 volts rms between the supply conductors or between either supply conductor and ground A protective ground connection by way of the grounding conductor in the power cord is essential Grounding the Instrument This instrument is grounded through the grounding conductor of the power cord To avoid electrical shock plug the power cord into a properly wired receptacle A protective ground connection by way of the grounding conductor in the power cord is essential for safe operation Danger Arising From Loss of Ground Upon loss of the protective ground connection all accessible conductive parts Gincluding knobs and controls that may appear to be insulating can render an electric shock Use the Proper Power Cord Use only the power cord and connector specified for your instrument Use only a power cord that is in good condition For detailed information on power cords and connections see Section 2 Installation in the User s Manual Use the Proper Fu
5. transducer to pro vide a calibration voltage which offsets the amplifiers output signal trace a prescribed amount Many medical transducers have a built in shunt cal resistor and therefore a jumper must be installed between E1 and E2 for a positive calibration input or from E1 to E8 if a negative calibration is desired The jumper can be stored in E1 to E3 position if amplifier is not being used in a transducer application When no shunt cal resistor is built into the transducer Ie strain gages the Deutsch input connector can be jumpered between pins 7 and 9 to complete the SHUNT CAL signal path and a know value resistor is then installed between E1 and E2 for positive calibration or E1 to E8 for negative calibration The Value of such a shunt cal resistor can be calculated using the following formula Rshunt 1x106 0 Ro 4NF Where 1 N Desired calibration signal size 2 lt Calibraton factor provides on the Transducer s certificate i e uV V mmHg 3 Ro the output resistance of transducer as found on the transducer s certificate Example N 10 cmHg F 50 mV V cmHg Ro 300 ohms 4 2 2 INPUT PROTECTION The Universal Amplifier is equipped with protection circuitry which will limit the input signal to the input amplifiers Back to back diodes are placed on each input line to clip the signal level at 15 volts This protection is capable of handling noise spikes or slight overvoltage signal but insufficient to pre vent damag
6. 00 3K offset 10K 9 ITEM 6 7 CONTROL full scale mvX100 mv ext mv mv bal cal momentary offset fine coarse cutoff hz low high notch filter calibrate zero push NOTE 1 NOTE 2 DESCRIPTION The step sensitivity control selects recorder and monitors full scale outputs in millivolts and millivolts x100 The input signal encounters the internal 100 to 1 switch and then is multiplied by the full scale attenuator and the calibrate setting to obtain the overall sensitivity of the amplifier Maximum measurement range is from 25 uV to 10 V full scale The ext mv position is used for operating with the optional Isolated Preamplifier Amplifier DC zero shift balance control see zero push The switch selects either DC or bridge transducer shunt calibration resistor see Note 2 The dc position injects 1 mV or 100 mV 950 uV or 5 mV internally selectable calibrate signal The dc position also overload restores the amplifier as well as defines the zero line when released Concentric 10 turn controls for zero suppression or balancing bridge transducers see cutoff The low and high switches select the bandpass of the amplifier for optimum signal characterization The dc offset position balances bridge transducer or provides zero suppression of unwanted DC signals The M position limits the amplifier response to 0 08 Hz or 2 0 seconds t
7. 60 Hz with 1kQ resistive inbalance Input to Reference 80 dB at 60 Hz with 1 kQ resistive inbalance Gain Accuracy 0 3 of full scale Linearity 0 1 of full scale in 25 mV full scale range increasing to 0 5 in the 250 mV full scale range Frequency Response 3 dB Small Signal 25 mV InputAC 0 016 Hz to 10 kHz DC DC to 10 kHz Full Power 250 mV Input AC 0 016 Hz to 10 kHz 10 DC DC to 10 kHz 41096 Amplifier Output Circuit Configuration Single ended to common Voltage 0 to 5 VDC linear range Impendance 100Q nominal short circuit proof Physical Exterior Dimensions H x W x D See Figure 1 5 6 1 x 8 1 x 18 cm 2 4 x 3 2 x 7 in 2 4 x 3 2 x 7 in 3 2 INCHES 7 2 4 INCHES 5 a INCHES 1 2 3 Catalog No 60 0013 Defibrillator Protector Impendance DC to 60 Hz Between Inputs gt 10 mQ with common mode signals up to 2 5 V Inputs to Chassis gt 50 mQ each input to chassis Leakage Current The combined leakage of the Defibrillator Protector and the Isolated Preamplifier is HA with 230 V RMS 60 Hz applied Defibrillator Protection The circuitry is designed to withstand up to 300 watt seconds of defibrillator pulse energy 1 3 SUPPLIES AND ACCESSORIES Catalog No Product 60 0109 Input Mating Connector Male 60 0225 Three Lead Non lsolated Patient Cable Kit 60 0129 Adapter Cable Deutsch to BNC 60 0280 Isolated Physiologic Pressure Transducer 60 0281 Miniature Isol
8. Manual for Catalog No 60 0125 User s Manual For Harvard s Research DC Signal Conditioner With Zero Suppression Catalog No 60 0125 The information contained herein is the exclusive prop erty of Harvard Apparatus except as otherwise indicat ed and shall not be reproduced in whole or in part with out explicit written authorization from the company The distribution of this material outside the company may occur only as authorized by the company in writ ing All information contained in this manual is the latest product information available at the time of printing The right is reserved to make changes at any time with out notice Harvard Apparatus Inc Printed 8 93 22 Pleasant Street South Natick Massachusetts 01760 3rd Printing Copyright 1990 Printed in U S A Safety SAFETY SUMMARY The general safety information is for both user and service personnel Specific WARNINGS and CAUTIONS will be found throughout the manual where they apply Terms in this Manual CAUTION statements identify conditions or practices that could result in damage to the equip ment or other property They will appear in boldfaced capital letters WARNING statements identify conditions or practices that could result in personal injury or loss of life They will appear in boldfaced capital letters Symbols in this Manual T This symbol indicates where cautionary information is to be found Terms as Marked on Equipment CAUTION indicates
9. S UNIVERSAL AMPLIFIER USER CONTROLS ISOLATED PREAMPLIFIER FRONT PANEL CONTROLS DESIGN FEATURE GENERAL PURPOSE DC BRIDGE AMPLIFIER WITH THE ISOLATED AMPLIFIER DESCRIPTION GENERAL UNIVERSAL AMPLIFIER MODEL 13 4615 58 INPUT SIGNALS Shunt Cal INPUT PROTECTION INPUT AMPS OFFSET AMPLIFIER SUMMING AMPLIFIER LOW CUTOFF FILTER RESET CIRCUIT CAL GENERATOR VERNIER GAIN AMP NOTCH FILTER HIGHCUTOFF FILTER SCALED MEAN OUTPUT AMP RANGE AMP OUTPUT DRIVER EXCITATION DRIVE GENERATOR ISOLATED PREAMPLIFIER MODEL 11 5407 58 INPUT CIRCUIT INPUT PROTECTION INPUT AMP ISOLATION AMPLIFIER DEFIB PROTECTOR MODEL 11 5407 59 a ott VPL LIST OF ILLUSTRATIONS FIGURE 1 1 1 1 1 Om K M AA Www 1 1 m TABLE 2 1 2 2 TITLE HARVARD MODEL 13 4615 58 UNIVERSAL AMPLIFIER HARVARD MODEL 11 5407 58 ISOLATED PREAMPLIFIER HARVARD MODEL 11 5407 59 DEFIB PROTECTOR ASM UNIVERSAL AMPLIFIER PHVSICAL DIMENSIONS ISOLATED PREAMP PHVSICAL DIMENSIONS INPUT CABLE CONNECTOR GENERAL PURPOSE CONNECTIONS TRANSDUCER CONNECTIONS BIOMEDICAL APPLICATION ISOLATED PREAMP CONNECTIONS DEFIB PROTECTOR CONNECTIONS FRONT PANEL CONTROLS UNIVERSAL AMPLIFIER USER CONTROLS FRONT PANEL 11 5407 58 UNIVERSAL AMPLIFIER USER CONTROLS ISOLATED PREAMPLIFIER BLOCK DIAGRAM LIST OF TABLES TITLE INPUT PIN LISTING POWER AND OUTPUT SIGNAL CONNECTIONS Z
10. SHUNT CAL EXC EXC SIG SHIELD OOOO HEART SOUND MICROPHONE 286700 T l N 2 l 1 If a shunt calibration resistor is not installed within the transducer or its connector install a jumper between pins 7 and 9 to allow instal lation of a shunt calibration resistor inside amplifier module PHONE PLUG DEUTSCH ADAPTER ASSEMBLY 11 5407 57 PHONE PLUG SHIELD UNIVERSAL AMPLIFIER 13 4615 58 UNIVERSAL AMPLIFIER 13 4615 58 ISOLATED PREAMPLIFIER 15VDC 6 A 15VDC 4 SIG UNIVERSAL 12 AMPLIFIER 11 11 5407 58 SHIELD o 2 6 Isolated Preamplifier Connections Figure 2 5 demonstrates the method of connecting the Isolated Preamplifier inputs to a patient and outputs to a Universal Amplifier Section 3 4 3 provide the instructions to insure the patient hookup is performed safely and properly 2 7 Defibrillator Protector Installation The Defibrillator Protector is designed for mounting directly to the Isolated Preamplifier Proper installation is easily performed by following these steps d 2 Disconnect the Isolated Preamplifier interconnect cable fro
11. Temp Gain with Time Gain with Line Gain with Temp Frequency Response Low Cut Off High Cut Off Notch Filter 1 of full scale 24 hrs 0 4 of full scale for a 10 line change 1 of full scale C 0 02 24 hrs 0 02 for 10 line change 0 03 C DC offset DC 05 1 3 1 3 10 30 100 Hz 3 dB 15 of indicated frequency 6 dB oct 0 05 10 30 100 300 1000 3000 10 000 Hz 3 dB 15 of indicated frequency 6dB oct 60 Hz reject filter minimum 20 dB at 60 Hz adjustable to 50 Hz Noise mV range input shorted 0 1 to 10 Hz 0 05 to 10 kHz Common Mode Rejection Calibrated Vernier Overload Recovery Time AC DC Offset Voltage uncalibrated Range Resolution Stability With Time With Temp With Line Noise Excitation Voltage Range Load Current Stability With Time 0 05 24 hrs With Line With Temp Noise Power Requirements Voltage 15 0 6 at 100 mZ Line and Load Regulation 0 5 Ripple Physical 4 uV peak to peak RTI lt 50 uV peak to peak RTI gt 90 dB at 60 Hz with 1 KQ imbalance in mV gt 70 dB in mVX100 10 turn vernier to multiply setting of attenuator or set transducer calibration from 0 5 to 10 5X Low cutoff filter Manual via front panel cal switch or external gate control 10 msec compatible with time oO N constant Up to 500
12. ated Physiologic Pressure Transducer 60 0114 Isotonic Muscle Transducer 2 1 GENERAL This section describes the checks and inspections that should be made upon receiving the Harvard Universal Amplifier Model 13 4615 58 Isolated Preamplifier Model 11 5407 58 and the Defibrillator Protector Model 11 5407 59 Installation procedures and typical signal input connections will also be discussed and diagrammed 2 2 Initial Inspection Prior to attempting any electrical connections or operation visually examine the unit for broken or loose knobs dented or nicked panels and broken or chipped rear connectors 2 3 Universal Amplifier Installation The Universal Amplifier Model 13 4615 58 may be mounted in any compatible Harvard Recorder of 4600 Amplifier Series cage Caution Power must be turned off when installing or removing amplifier modules 2 3 1 Insertion To install the amplifier into its appropriate slot a Slide the amplifier into the enclosure until the rear output card edge connector is engaged b Tighten the rear retaining screw until the amplifier front panel is flush with the edge of the enclosure DO NOT OVERTIGHTEN This locks the preamplifier into the enclosure C The 12 pin Deutsch input cable connection at the rear of the amplifier module utilizes a locking ring which snaps into place as a securing device Install the input signal cable by aligning the blue line on the locking ring on the cable connector with the polar
13. cale control to off Adjust calibrate dial vernier to 1 0 reading Select dc position on low cutoff switch Put high cutoff switch in 1k position Start recorder and adjust trace for chart center Set mvX100 mv ext mv switch to mv Depress zero push switch to zero Place full scale control to 1 Adjust mv bal potentiometer to center trace Select 10 position with full scale control Release zero push switch from zero Place low cutoff switch to dc offset position Using the coarse offset and fine offset controls position the trace to chart center While changing the full scale control to higher sensitivity positions insure the tracing remains at chart center by adjusting the offset controls Now the amplifier balance has been completed Four Transducers are sold through Harvard for the medical field P23ID Harvard Statham Isolated Blood Pressure 369500 8916 P50 Harvard Statham Miniature Isolated Blood Pressure 369500 8904 UC2 Harvard Statham Bidirectional Isometric Force 369500 8640 Harvard Metripak Isotonic Muscle Transducer 793341 04042 UL5 Microscale Accessory for the UC2 Transducer 369500 8621 Other transducers that use a 5 VDC excitation voltage and have outputs 25 uV full scale can be used 3 5 3 WITH THE ISOLATED PREAMPLIFIER A Preliminary Set up The following steps are used t
14. e when a defibrillator is used The maximum current specification for each of the diodes is 50 mA 4 2 3 INPUT AMPS The input amplifiers are basically voltage followers with a switch selectable gain possible If the mvX100 mv ext mv switch is in the mvX100 or ext mv positions the amplifiers have a unity gain The selections of mv on the switch inserts R3 and R7 into the circuitry and provides a gain of approxi mately twenty through the input amplifiers The ability to balance the output of the positive and negative input amps is provided through R18 and R19 The mvX100 mv ext mv switch selects the amount of common mode rejection to be inserted into the positive amplifier s output When in mv position R19 will supply proper compensation while R18 is active in mvX100 and ext mv The common mode rejection CMR output is biased when the low cutoff switch is placed in dc offset selection 4 2 4 OFFSET AMPLIFIER The offset circuit is designed to reduce or eliminate a DC voltage component of an incoming signal If the input signal varies between 5 mVDC and 10 mVDC the area of interest does not include that below 5 mVDC By interjecting a 5 mVDC offset the area of interest can be expanded to give greater detail and a more useful output The fine offset and coarse offset controls utilize the 10 VDC refer ence output to supply the offset amplifier with its input The offset amp provide
15. ersal amplifier form 0 5 to 10 5 times the full scale setting This adjustment also allows the operator to calibrate the system when used in a transducer application 4 2 10 NOTCH FILTER In some situations a line frequency signal interferes with the true input and distorts the output beyond acceptance The notch filter is designed to minimize this problem by filtering out the line frequency noise The notch filter switch selects whether the filter circuit is used in or not out Internal potentiometer R50 adjusts the center of the notch filter to either a 50 Hz or 60 Hz line frequency NOTE Universal Amplifiers that were built in early production lots used a 200 kQ potentiometer for R50 and there was an insufficient range of adjustment for50 Hz applications The new 500 kQ pot allows adjust for both 60 Hz and 50 Hz line frequencies 4 2 11 HIGH CUTOFF FILTER The rolloff frequency of the high cutoff filter is selected by the high cutoff switch and determines the upper limit of the Universal Amplifier bandpass response The M switch position provides a mean or average output to the range amp and output driver This M output is the same signal which is nor mally used by the scaled output amp 4 2 12 SCALED MEAN OUTPUT AMP The scaled mean output amplifier generates a continuous average output not affected by the full scale or high cutoff switches The M output form the high cutoff f
16. he ground potential to be sent through the cal switch to the vernier gain amplifier In this way the amplifier can be reset and the zero baseline defined by a remote switch closure between card edge pins C and D The second reset method is holding the cal switch in the dc position The reset circuit will again be activated by turning on the relay drive transistor and charging the holding capacitor In this reset mode the cal switch applies the cal generator output to the vernier gain amp Upon release of the cal switch the holding capacitor in the reset circuit keeps the reset relay energized for approximately 400 ms Therefore the output of the Universal Amplifier during a dc calibration sequence will be first at the cal level followed by a 400 ms zero ground baseline and then a return to a normal input follow ing signal 4 2 8 Cal Generator The cal generator utilizes the 10 VDC reference voltage to produce a known calibration voltage An internal switch S2 permits selection of a 1 mV or 50pV output level In addition two separate voltage divider networks are used to generate the outputs required for calibration when the mvX100 mv extmv switch selects either mv or mvX100 mode 4 2 9 VERNIER GAIN AMP The vernier gain amplifier is the only stage of the module which has the capability of the stepless front panel gain control The calibrate vernier can vary the gain of the univ
17. ier for usage in the isolated portion of the preamplifier 4 4 DEFIBRILLATOR PROTECTOR Model 11 5407 59 The Model 11 5407 59 Defibrillator Protector is designed specifically to protect the Model 11 5407 58 Isolated Preamplifier from defibrillator pulses with peak energy delivery up to 300 watt sec The Defibrillator Protector reduces the high voltages in two stages The first section consist of spark gaps which short out any voltages above 1000 volts The second stage has clamping transzorbs which hold the maximum signal to 18 2 volts
18. ilter is conditioned to produce a 10 VDC full scale output at card edge connector pin J The gain of the scaled output amp is controlled by R79 scale select resistor which plugs into E6 and E7 The amplifier is shipped with a 5 kQ resistor installed that give a scale factor of 10 but it can be replaced with other values to produce different full scale factors The following formulas will aid in selecting the correct resistor value for a specific appli cation 4 2 13 RANGE AMP The range amplifier receives its signal input from the high cutoff filter and control inputs from the mvX100 mv ext mv and full scale switches The mv or ext mv selection boosts the amplifier gain five times while mvX100 does not request an increase in gain The mv position also provided a gain of 20 in the input amp for a total of 100 times increase in sensitivity to this point while the mvX100 selection has maintained unity gain throughout An ext mv input received unity gain in the input amp and a five times increase in the range amp To determine the overall system increase this far the 20 times boost in the Isolated Preamplifier must be figured and this brings the total to 100 times 4 2 14 OUTPUT DRIVER The output drive supplies the REC OUT and MON OUT signals for hard copy printing The signals from the range amp are received through an attenuator string which is switched by the full scale selec tions This fina
19. ime constant for mean pressure determination Time constant can be changed internally The slide switch allows for 60 Hz noise rejection The notch frequency can be adjusted internally for 60 or 50 Hz A dial vernier sensitivity control that provides overlapping ranges with stepless adjustment from 0 5 to 10 5 times any setting of the full scale control times mvX100 mv ext mv switch The dial vernier is also used for the calibration factor of strain gage transducers See Note 1 This latching switch disconnects the signal source and shorts the amplifier inputs to ground This allows for rapid determination of the amplifier zero balance when the low cutoff selector is in the dc position Example A typical blood pressure transducer has a calibration factor of 50 uV V excitation 10 mmHg Multiplying 50 uV excitation times 5 volts times the full scale load pressure of 100 mmHg equals 2 5 mv at 100 mmHG Therefore if you dial 2 5 on the calibrate control select mv and set the full scale to the 1 position you will have 100mmHg full scale or 1 decimeter Hg full scale A shorter method would be to divide the calibration factor by 20 and dial the number for example 50 20 2 5 Harvard Statham Blood Pressure Transducers purchased from Harvard Recording Systems Division have shunt resistors installed equivalent to 100 mmHg 13 33 kilopascal 3 3 UNIVERSAL AMPLIFIER USER CONTROLS Item numbers lis
20. izing key See Figure 2 1 on the amplifier connector Push the cable connector in until the locking ring snaps into place and or the orange ring behind the locking ring on the connector shell becomes visible Caution This type of connector Deutsch can be damaged beyond repair by attempting to twist or turn the locking ring Do not attempt to tighten this connector by screwing or turning the locking ring Hearing the ring snap and or observing the orange ring behind the locking ring indicates total insertion has been attained 2 3 2 Removal a Disconnect the input connector by pulling back on the locking ring b Loosen the rear retaining screw The preamplifier will move forward 1 8 of an inch C Carefully slide the entire amplifier out of the enclosure 2 4 Universal Amplifier Input Connections This amplifier unit may be used as a general purpose AC or DC amplifier as a transducer ampli fier or as a biophysical signal conditioner Table 2 1 gives a complete input pin and signal listing and Table 2 2 indicates the connections for power and output signals available on the card edge connector The amplifier cage may have spade lug terminals or push on terminals depending upon the model and manufacture date Figure 2 2 gives a typical connector of the Universal Amplifier as a general purpose amplifier while Figure 2 3 shows a schematic for a transducer input Use of Heart Sound Microphone 286700 and a Phone Jack Deutsch Adapter Assembly 11 5407
21. l stage then boosts the signal by a factor of 10 for sufficient output drive capabilities 4 2 15 EXCITATION DRIVE GENERATION The excitation drive generator utilizes the 10 VDC output of the 10 volt reference to derive the excita tion voltage for transducer applications The standard excitation output signal are 2 5VDC with EXC on card edge pin 9 and JEXC on pin 8 There is an internal switch 53 which provides a method of reversing the two outputs If the transducer being used requires a different exci tation voltage R89 should be removed by unplugging the present resistor from E4 and ES see Figure 3 2 and replaced with another value of resistance The following formula will determine the necessary resistor in kQ 4 3 ISOLATED PREAMPLIFIER Model 11 5407 58 The purpose of the Harvard Isolated Preamplifier is to provide signal conditioning and amplification near the signal source this reduces the problem of noise and cable capacity effects on very high impedance signal sources The Isolated Preamplifier also provides electrical isolation between the signal source and the measurement equipment The preamplifier is intended for use with and powered by the Harvard Universal Preamplifier 4 3 1 INPUT CIRCUIT The input signals and may be AC or DC compled as selected on the AC DC switch see Figure 4 2 Once coupling is determined the signals proceeds to the zero on switch When in the zero position depressed
22. m the Universal Amplifier Remove the front two cover screws from the Isolated Preamplifier Insert the three output pins of the Defibrillator Protector into the input jacks of the Isolated Preamplifier Align the mounting holes on the rear bracket of the Defibrillator Protector with the front two cover screw holes on the Isolated Preamplifier Install the two screws to secure the Defibrillator Protector to the Isolated Preamplifier NOTE These screws provide the ground connection for the Defibrillator Protector and must be installed 2 8 Defibrillator Protector Connection Installation of the input connections to the patient must be performed in accordance with Section 3 4 3 Figure 2 6 shows the input output configuration using the Defibrillator Protector Isolated Preamplifier and the Universal Amplifier 3 1 GENERAL This section illustrates and describes the controls of the Universal Amplifier Model 13 4615 58 and Isolated Preamplifier Model 11 5407 58 Complete operating instructions are also provided 3 2 UNIVERSAL AMPLIFIER FRONT PANEL CONTROLS Item numbers listed below refer to circled numbers in Figure 3 10 OG 1 fF Universal full scale mv zero push lt e cal 25 1 O 5 5 10 25 25 1 Q Off 05 in out notch filter mv x100 Off miy 1 Ov ext qiy offset calibrate fine coarse cutoff low hz high 3 1 10 30 4 3 M 100 05 10 300 30 30 1K dc 1
23. mV in mV range up to 10 V in mVX100 range 2 uV in mV range 200 in mVX100 range After 30 minute warm up i 0 02 24 hrs 0 05 C 0 02 for 10 line change 50 uV RTI on mVX100 range uV RTI on mV range 5 0 5 mV 22 5 V nominal balanced to chassis 50 mA maximum adjustable via plug in resistor 0 02 for a 10 change in line 0 05 C 0 1 P P from DC to 1kHz 5 mV RMS maximum Exterior Dimensions H x W x D See Figure 1 4 1 2 2 Catalog No 60 0112 Amplifier Input Circuit Configuration Impedance Differential and balanced to reference gt 1000 mQ shunted by lt 30 pF in DC mode 100 mQ and 30 pF in AC mode Sink Rise Leakage Current 10 pA at 230 V RMS 60 Hz input to chassis Noise inputs shorted ext mV only 0 05 to 10 Hz 0 05 to 10 kHz Input Current lt 2 u peak to peak RTI lt 12 uV peak to peak RTI lt 100 pA at 25 C either input Instability After 30 minute warm up Zero with Time 4 of full scale 8 hrs Zero with Line 0 1 for a 10 line change Zero with Temp 2 of full scale C Gain with Time 0 05 24 hrs Gain with Line 0 05 for a 10 line change Gain with Temp 0 05 C Maximum Safe Voltage 50 V peak input to reference 500 V peak input to chassis Maximum Common Mode Input to Chassis 100 dB at
24. n ext mv 3 Only after all leads and or electrodes are connected should any attempt be made monitor biophysical signals 4 Release zero on switch to on position 5 Before disconnecting or rearranging any leads or electrodes depress the zero on switch to zero position on Isolated Preamplifier SECTION IV DESCRIPTION OF OPERATION 4 1 GENERAL The Universal Amplifier Model 13 4615 58 is a remarkable device because the high input impedance wide bandwidth low noise and low drift capabilities As evidence to its built in versatility the Universal Amplifier can be used for general purpose AC or DC signal conditioning measurement of bioelectric phenomena or strain gage transducer applications This amplifier module can be combined with the Isolated Preamplifier Model 11 5407 58 and Defibrillator Protector Model 11 5407 59 to per form high quality ECG or EEG monitoring without experiencing signal loss and noise while still being protected against defibrillator damage 4 2 UNIVERSAL AMPLIFIER Model 13 4615 58 This discussion will follow a block diagram Figure 4 1 and will cover not only the basic function of each block but also the unusual characteristics Generally speaking the direction of the presentation will proceed along the normal signal data path with ancillary blocks covered as their functions come into play 4 2 1 INPUT SIGNALS SHUNT CAL Normally the SIG and QSIG input signal
25. o balance the system prior to installing patient leads 1 Install the Universal Amplifier and connect the Isolated Preamplifie interconnect cable If the Isolated Preamplifier will be concurrently used with stimulators electrocauteries or defibrillators insure a Defibrillator Protector is installed before the balancing procedure is performed 2 Set the Universal Amplifier switches to these positions full scale off calibrate 1 0 low cutoff dc high cutoff 1k 3 Start recorder and adjust trace to chart center 4 Place mvX100 mv ext mv to mv 5 Depress zero push button to zero 6 Put full scale control to 10 7 Adjust mv bal potentiometer to position trace at chart center 8 Release zero push 9 Place mvX100 mv ext mv to ext mv 10 Depress zero on switch on Isolated Preamplifier to zero 11 Check to insure the trace is at chart center If not adjust mv bal to center trace 12 Release zero on switch to on position 13 Input 5 mvDC into the Isolated Preamplifier The pen should deflect to the left or right side of the chart depending upon the signal polarity B Patient Lead Connection The following steps should be completed to protect against possible microshock haz ards when placing patient leads 1 Depress zero on switch on the Isolated Preamplifier to zero position 2 Insure mvX100 mv ext mv switch is i
26. olated Preamplifier when usage of a defibrillator or other stimulators in antici pated Ra 7 2 1 Defib Protector Saal 1 2 Specifications 1 2 1 Model 13 4615 58 Amplifier Input Circuit Configuration DC AC Impedance mv and mvX100 Input Current Measurement Range mVX100 mV or ext mV Attenuation Maximum Safe Voltage Internal Calibration DC Signal Source Attenuator Inaccuracy Non linearity Instability Differential and balanced to chassis Differential and balanced to chassis Range 100 mQ each input to chassis lt 100 pA either input at 25 C 2 5 mV full scale to 10 V full scale 25 uV scale to 250 mV full scale 0 05 0 1 0 25 0 5 1 2 5 5 10 25 full scale and OFF mV X100 mV ext mV switch and calibrate vernier dial 120 V RMS each input to common mV ext mV Selectable between 50 uV an 1 mV with in 1 at 25 C 5 uV C mVX100 Selectable between 5 mV and 100 mV within 1 at 25 C 0 5 of calibrated step 0 1 of full scale after 30 minute warm up DC Mode 500 uV full scale Zero with Time Zero with Line Zero with Temp Gain with Time Gain with Line Gain with Temp 4 of full scale 8 hrs 0 1 of full scale for a 10 line change 2 of full scale C 10 0 02 24 hrs 0 02 for 10 line change 0 03 C AC Mode 50 uV full scale by design Zero with Time Zero with Line Zero with
27. s are routed through the zero push switch to the input protectors When the switch is depressed the inputs to the amplifier is shorted to ground These shorted inputs are very useful when the user is calibrating the unit or wanting to identify the reference or baseline dwy ueg 4 1 1 4 0290 9189410 8 9 8 N oxa b 01650065 oxa wer uo 918 0 AOL NOL 1 13s34 ALOWSY 1 89 JONI OSHO MO 0 4 0 1 0 4OP 191114 pomno HOMO MOL 10188055 129 YOUMS AW 00 XAW HOA OLF S10 99 01q SUL 0197 YO ois TWO uo 0182 The SHUNT CAL input signal is activated during a transducer application when the cal switch is held in the shunt position A known value of resistance is connected across one arm of the
28. s the desired signal correction through the CMR circuit when dc offset is selected on the low cutoff switch 4 2 5 SUMMING AMP The summing amplifier has the responsibility of combining the positive and negative input amplifier output signals Although the negative input amplifier has no alteration made to its output the positive input amplifier output will have common mode rejection correction inserted This CMR signal can also be biased by the offset amplifier when dc offset mode is selected on the low cutoff switch 4 2 6 LOW CUTOFF FILTER The low cutoff switch controls the function and limits of the low cutoff filter When dc or dc off set is selected the filter is disabled and the summing amp output is resistively coupled to the next stage The remaining positions on the switch will provide capacitive coupling of the summing amp sig nal with 3 dB steps from 05 Hz and will establish the lower limit of the Universal Amplifier s bandpass 4 2 7 RESET CIRCUIT The output from the low cutoff filter passes through a set of contacts on the reset relay The reset cir cuit which drives this relay can be activated two ways by remote reset or by depressing cal switch to de The remote reset signal places a ground on the input of the reset circuit which turns on the relay drive transistor and charges a holding capacitor Pulling in the relay causes the low cutoff filter output to open and t
29. se To avoid fire hazard use only a fuse of the correct type voltage rating and current rating as specified in the parts list for your instrument Do Not Operate Without Covers and Panels Installed To avoid personal injury and equipment damage the user should disconnect power before removing covers panels or any grounding straps Reinstall covers panels and any grounding straps before reconnecting power WARNINGS For Authorized Service Personnel Do not perform internal service or adjustment of this instrument unless another person capable of rendering first aid and resuscitation is present Dangerous voltages exist at several points in this instrument To avoid personal injury do not touch exposed connections or components while power is on Disconnect power before removing protective panels soldering or replacing components TABLE OF CONTENTS Section 1 General Information INTRODUCTION UNIVERSAL AMPLIFIER MODEL 13 4615 58 ISOLATED PREAMPLIFIER MODEL 11 5407 58 DEFIBRILLATOR PROTECTOR MODEL 11 5407 58 SPECIFICATIONS MODEL 11 4615 58 MODEL 11 5407 58 MODEL 11 5407 59 SUPPLIES AND ACCESSORIES INSTALLATION GENERAL INITIAL INSPECTION UNIVERSAL AMPLIFIER INSTALLATION UNIVERSAL AMPLIFIER INPUT CONNECTIONS ISOLATED PREAMPLIFIER INSTALLATION ISOLATED PREAMPLIFIER CONNECTIONS DEFIBRILLATOR PROTECTOR INSTALLATION DEFIBRILLATOR PROTECTOR CONNECTIONS OPERATION GENERAL UNIVERSAL AMPLIFIER FRONT PANEL CONTROL
30. ted below refer to Figure 3 2 E1 E2 E3 E8 EA 55 E6 E7 S 2 S 3 9 Jacks for selecting or shunt calibration resistors Jacks may be used to installed desired calibration resistor is none supplied Jacks for setting excitation voltage to 5 0 V or 10 0 V Jacks for setting mean output scale factor Calibration Voltage selected at either 50 uV or 1 mV Excitation Polarity Select normal or reverse Provides direct output with cable assy CL 612311 between TP F and J9 Provides mean output with shorting plug connector 296520 1 on J9 3 4 ISOLATED PREAMPLIFIER FRONT PANEL CONTROLS ITEM Item numbers listed below refer to circled numbers in Figure 3 3 CONTROL AC DC zero on DESCRIPTION This latching pushbutton selects AC or DC coupling of the Isolated Preamplifier AC response is from 0 016 Hz 3 dB Best common mode is achieved in dc position This latching push button disconnects the input source signal and shorts the input to ground In AC mode an overload can be restored by placing the switch in zero position 3 5 DESIGN FEATURE The 13 4615 58 Universal Amplifier is designed to be three amplifiers in one It operates extraordinarily as a general all purpose AC or DC Amplifier It also accepts signals from pressure force and strain gage displacement transd
31. ucers directly in units of measure When used with the addition of the 11 5407 58 Isolated Preamplifier it is capable of measuring high frequency nerve potentials as well as DC coupled eye potentials and nearly any other signal in the bioelectric field 3 5 1 GENERAL PURPOSE As an example assume a positive DC input of Imv maximum is to be fed into the Universal Amplifier with the signal to be recorded on a chart recorder The following setup procedures will prepare the sys tem for operation 1 Install the amplifier module and connect the input cable Place full scale control to off Adjust calibrate dial vernier to 1 0 reading Select dc position on low cutoff switch Start recorder and adjust trace for chart center Set mvX100 mv ext mv switch to mv Depress the zero push switch to zero Place full scale control to 1 Release zero push switch from zero Adjust trace to right chart edge Set mvX100 mv ext mv seitch to mvX100 Input 1 mVDC signal and pen should move to left chart edge Refer to Section 2 4 for interconnection information Accessories to assist in making necessary circuit connections are listed in Section 1 3 3 5 2 DC BRIDGE AMPLIFIER When utilizing a DC Bridge or transducer input the following steps will balance the system for proper operation Install the amplifier module and connect the input cable Place full s
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