Summary of Contents for natus Grass S88X
- Page 1 ® S88X utput quare ulSe timulatOr USER & SERVICE MANUAL Release D Phone 401.773.2600 • Fax 401.732.7097 • Technical Support 877.472.7779 • E-mail grass@natus.com Web site: www.natus.com Manual Part Number M643H05...
- Page 3 ’ ublisher otice Natus Medical Incorporated DBA Excel-Tech Ltd. (XLTEK) 2568 Bristol Circle Oakville, ON L6H 5S1 Canada phone: +1 401.773.2600 fax: +1 401.732.7097 toll-free: 1.877.472.7779 (USA only), 1.855.554.3184 (Canada only) email: grass@natus.com www.natus.com EUROPEAN AUTHORIZED REPRESENTATIVE: Natus Europe GmbH Robert-Koch-Str.
- Page 4 , SzAC , TWin , TWinLOOK and TREA are trademarks of ® ® ® ® ® ® Natus Medical Incorporated. Other brand and product names are trademarks or registered trademarks of their representative holders. Printed in the United States of America...
- Page 5 mPortaNt This manual is subject to periodic review, update, and revision. Customers are cautioned to verify that the manual’s information applies to the software and hardware present in the equipment. This product performs as described in this manual, and in accompanying labels and/or inserts, when assembled, operated, maintained, and repaired in accordance with the instructions provided.
- Page 6 CONSULT GRASS IF YOU HAVE ANY CONCERNS ABOUT SAFE APPLICATION, PARTICULARLY WHEN USED WITH OTHER EQUIPMENT. NATUS MEDICAL INCORPORATED WAIVES THE RESPONSIBILITY WHATSOEVER FOR ANY INJURIES INCURRED TO THE OPERATOR OF THIS INSTRUMENT, OR TO ANY ANIMAL OR HUMAN SUBJECT AS A RESULT OF THE...
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Page 7: Table Of Contents
Table of Contents 1. s & s ..........1-11 PecificatioNs ymbols lossary ..................1-11 pecificationS ................1-12 loSSary ymbolS 2. i ................. 2-13 NtroductioN ................2-13 afety nformation CAUTION ...................2-13 WARNING ..................2-13 ..........2-14 lectromaGnetic ompatibility nformation 3. g ..............3-15 eNeral oNsideratioNs & c ..............3-15 pplicationS... - Page 8 5. e ..............5-25 xPlaNatioN of oNtrols ..............5-25 xplanation ontrolS ....................5-25 oWer & e .................5-25 etup nter ccept & D ...............5-26 rain uration S1/S2 t ............5-26 iminG arameter anGeS ...................5-26 RAIN ................5-26 RAIN URATION S1/S2 R ...................5-26 S1/S2 D .................5-26 elAy S1/S2 D .
- Page 9 ................7-40 aSic peratinG oDeS ..................7-40 inGle ulSeS (S1 S2) ..............7-41 epetitive ulSeS (S1 S2) ..............7-41 inGle rainS (rt) S1 S2 ............7-42 epeatinG rainS S1 S ................7-43 pecial oDeS S1 D .................7-43 elAy ..............7-43 RAIN URATION S2 S ................7-44 pecial oDeS S1 (SS) .................7-44 WITh S1 T (PT) ...............7-45 RAIN...
- Page 10 Table of Contents...
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Page 11: Specifications
Specifications & Symbols Glossary Specifications Train Rate (S1 and S2) ������ 1/100 sec to 99 TPS Train Duration �������������� 1 msec to 99 sec Rate (S1 and S2) ������������ 1/100 sec to 1000 PPS Pulse Delay (S1 and S2) ���� 10 µsec to 99 sec Pulse Duration (S1 and S2) �... -
Page 12: G Lossary Of S Ymbols
lossary of ymbols Warnings & Cautions 1-12 Chapter 1 Specifications... -
Page 13: Ntroduction
Introduction Safety Information CAUTION Misuse of this product may constitute a safety hazard. Please review the following. WARNING The S88X output is not isolated. Do not use on humans. For use by qualified persons only. Removal of the S88X Stimulator cover may expose you to lethal voltages and other hazards. -
Page 14: Lectromagnetic Ompatibility Nformation
The S88X cabinet has slots for ventilation purposes to prevent component overheating. a. Never cover the slots with cloth or any other material. b. Avoid placing the S88X over radiators or heat registers. c. Never place the stimulator in an enclosure unless proper ventilation is provided and all other related precautions taken. -
Page 15: General Considerations
General Considerations Applications & Capabilities The S88X is a dual output general purpose electrical stimulator for nerve and muscle stimulation procedures. Following in the tradition of Grass quality and reliability, the S88X is the next generation of the Grass stimulator line. New Features Include: •... - Page 16 The S88X makes use of current technology in it’s design. A DAC (Digital Analog Converter) is used to generate the output pulses, and a FPGA (Field Programmable Gate Array) to reduce the size. Software can be updated via the USB interface connector located on the rear chassis.
- Page 17 The display is divided vertically. The left side displays the selected channel, S1 or S2, function, type of pulses; monophasic, biphasic, or twin, and the output amplitude (volts). The right side of the display is used for displaying the Delay, Duration, Rate, Train Rate and Train Duration. The graphical symbols accompanying the timing values indicate how the values apply to the waveforms.
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Page 18: Ccuracy Aveform
& W ccuracy avEform All timing parameters are crystal controlled and are accurate to within ±0.00005%. This feature provides repeatability for the most demanding applications. Both the rise and fall times of the S88X output pulses are approximately 4 microseconds. Calibration of the 10 sec duration is based on the average width of the pulse. -
Page 19: D Uty C Ycle
oltaGE EquirEmEnts The S88X has an IEC320 Power inlet for a standard 3-wire AC cable. The unit accepts 115 to 230 volts, 50/60 Hz. The maximum power is 100 watts. The S88X power inlet accepts a standard 3-wire AC Power cord. The input is 115-220 volts, 50/60 Hz and 100 watts. -
Page 20: M Ounting & I Nstallation
The 50% duty cycle can never be exceeded if the DELAY and DURATION controls are set for less than 500 µs. If the DELAY circuit is not being used, always set the DELAY controls for less than 500 µs. Most triggered circuits, such as those in the S88X, cannot be driven satisfactorily over 90% of their duty cycle. -
Page 21: Description Of Circuits
Description of Circuits General To distinguish the various functions of the S88X, color coding has been used. S1 functions = Blue S2 functions = Green RATE, DELAY and DURATION = Yellow SYNC terminals = Gray Most switches are membrane touch-pad type offering extreme reliability. Settings are displayed on the front panel, bright, vacuum florescent display. -
Page 22: O Utput C Ircuit
utPut ircuit The S88X is driven by a Digital Signal Processor (DSP). To create the output waveforms the DSP writes 16-bit binary values to a Digital to Analog Converter (DAC). The DAC puts out a voltage that corresponds to each value. - Page 23 These applications with this type electrode submerged in baths present a very low resistance circuit load to the stimulator output requiring the stimulator to deliver large amounts of current. Most stimulators are not capable of driving large currents and tend to overload when used for this application.
- Page 24 4-24 Chapter 4 Description of Circuits...
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Page 25: Explanation Of Controls
Explanation of Controls Explanation of Controls The following section describes the S88X controls and their function. oWer POWER is a rocker switch to control the AC power supplied via the AC cable assembly. This switch turns the S88X on or off. &... -
Page 26: T Rain R Ate & D Uration
& d raiN uratioN The TRAIN RATE touch-pad control displays the current value. The TRAIN RATE is set with the TIMING left and right arrow touch-pad controls and the thumbwheel control. TRAIN DURATION touch-pad control displays the current value. The TRAIN DURATION is changed with the TIMING left and right arrow touch-pad controls and the thumbwheel control. -
Page 27: S1 & S2 C Ontrols
s1 & s2 c oNtrols unctiOn The FUNCTION touch-pad control is used in conjunction with the TIMING thumbwheel control to select the S1 and S2 modes. The modes are listed below. S1 Modes: These four modes allow S1 and S2 to operate as completely independent stimulators. -
Page 28: S1 & S2 P Ulses
S1 & S2 p ulSeS The S1 PULSES and S2 PULSES buttons allow selection of three types of stimulus waveforms; Figure 5-1a: MONOPHASIC (MO), BIPHASIC (BI), and TWIN (TW) PULSES. Monophasic Waveform Monophasic pulses are single phase positive pulses starting at zero volts and rising to a preset voltage, then returning to zero. -
Page 29: O Utput A Mplitude
utPut mPlitude A thumbwheel dial and right and left arrow buttons control the S1 and S2 stimulus amplitude (voltage) as displayed on the front panel. Values between 0.25 and 24 volts can be selected. A four-pin connector provides the output stimulus and supply voltages for the optional Grass Stimulus Isolation Units. -
Page 30: S Ync I N (S Ynchronous I Nputs )
yNchroNous NPuts The Sync Inputs are set up as “pull down” inputs. Without any connection to them, they are at a +5 volt level. When a connection is made from an external device, the +5 volts is “pulled down” to “0” volts awaiting a +5 volt trigger. -
Page 31: M Onitors
oNitors S1/S2 leD m OnitOrS Green LEDs adjacent to the S1 OUT and S2 OUT connectors illuminate with each stimulus pulse. leD m utput OnitOrS Green LEDs adjacent to the S1 OUTPUT ON/OFF and S2 OUTPUT ON/OFF touch switches light when this function is selected. utput OnitOr A BNC connector on the S88X rear panel provides a low level waveform... -
Page 32: D Uty C Ycle L Imitations
ycle imitatioNs Duty cycle is defined as the ratio of the time that the stimulus is on to the total period or interval. 100% duty cycle occurs when a circuit is continuously on, as with DC. Since the time from the start of one pulse to the start of the next pulse in seconds is the reciprocal of the frequency or PPS (Time = 1/Frequency), the Delay and Duration controls should not be set greater than about T=1/2F, which is 50% duty cycle. -
Page 33: Computer Control
Computer Contol Computer Control S88X can be controlled by a computer connected via a USB cable. There are several methods for doing this: S88X Host Control Software provides a virtual control panel for S88X which provides all of the features and settings accessible from the hardware front panel. - Page 34 Programmer API. A driver (.dll) and programming interface allows C++ and C# developers to control the S88X. A demo C# interface is available as an example. A Python module and driver allows users of this popular, easy-to-use scripting language to control S88X functions. Settings can be changed from the command line or loaded from saved scripts.
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Page 35: Setup
Operation Setup The SETUP touch-pad control sets several modes as seen on the display. These are: • DUTY CYCLE LIMIT • CHOOSE STIMULUS ISOLATION UNITS • LOAD SETUP • SAVE SETUP • TRAIN PARAMETERS FUNCTIONS The ENTER/ACCEPT touch-pad control is used to enter and accept changes made in the SETUP. -
Page 36: C Hoose S Timulus I Solation U Nits
hoose timulus solatioN Nits To connect the Grass Stimulus Isolation Units to the S88X proceed as follows. Press the SETUP touch-pad control. Toggle down the list to CHOOSE STIMULUS ISOLATION UNITS by using the TIMING thumbwheel control. Press the ENTER/ACCEPT touch-pad control. Use the TIMING thumbwheel control to select S1 STIMULUS ISOLATION UNITS and press the ENTER/ACCEPT touch-pad control again. -
Page 37: Oad Etup Ave Etup
& s etuP etuP When the POWER to the S88X is turned on, the S88X will display the last set of parameters used. In addition, it is possible to save up to 9 sets of stimulating parameters for use again. S88X p etting up the arameterS... -
Page 38: T Rain P Arameters F Unctions
raiN arameters uNctioNs To select TRAIN PARAMETERS FUNCTIONS proceed as follows. Press the SETUP touch-pad control. Toggle down the list to TRAIN PARAMETERS FUNCTIONS by using the TIMING thumbwheel control. Press the ENTER/ACCEPT touch-pad control. S1 TRAIN DELAY, S2 TRAIN DELAY, TYPE OF TRAIN PARAMETERS, and TRAIN SYNC LOCATION will be displayed. -
Page 39: Train S Ync L Ocation
rain OcatiOn The Train synchronous output can be selected to be coincident with the start of the train or at the end of the train duration. Selection is made by the following procedure. Select SETUP, then TRAIN PARAMETERS FUNCTIONS, then ENTER/ACCEPT. In the display, select TRAIN SYNC LOCATION, then ENTER/ACCEPT. -
Page 40: B Asic O Perating M Odes
asic pEratinG oDEs iNgle ulses Single Pulses (S1 or S2, with or without delay) initiated from the S88X SINGLE button. Turn the POWER switch on. Select S1 (or S2) FUNCTION. Use TIMING thumbwheel to select SINGLE PULSE (SP). If delay is required, select the DELAY pushbutton. The display indicates the delay values in seconds. -
Page 41: R Epetitive P Ulses (S1 Or S2)
ePetitive ulses Select S1 or S2 FUNCTION, and use the thumbwheel to select S1 (or S2) REPEATING PULSES. Depress the TIMING RATE button to access the rate timing. Use the left and right arrow keys and the thumbwheel to select a rate between 0.01 and 1000 PPS (Pulses per Second). -
Page 42: R Epeating T Rains (Rt) S1
If it is desired to provide a Delay before the Train, do the following: Depress the SETUP button, then use the TIMING thumbwheel to select the TRAIN PARAMETERS FUNCTIONS from the list on the display. Depress the ENTER/ACCEPT, button and select the S1 TRAIN DELAY (or the S2 TRAIN DELAY) using the TIMING thumbwheel. -
Page 43: S1 S Pecial M Odes
s1 s Pecial odes S1 D ync tO elay This mode is intended for applications when an external device is to be used to control the S1 output. The connection from the external device must connect to the S1 DELAY SYNC IN and be a positive 5 volts for triggering to occur. -
Page 44: S Ync With S1 (Ss)
s2 s Pecial odes S1 (SS) ync with In this mode, S2 is synchronous with S1. Each S1 pulse will produce an S2 pulse. If delay is required between the S1 and S2 pulses, the S2 DELAY can be used. For example, it is desired to deliver monophasic pulses at the same pulse rate of 50 PPS from S1 and S2 outputs but separated by a 20 millisecond delay. -
Page 45: Ost S1 Train (Pt)
S1 t (pt) rain This mode provides a Train from S1 followed by a single pulse from S2 (post train). The Delay from the end of the Train to the onset of the post train pulse can be set using the S2 DELAY. The post train S2 pulse duration is set by the S2 DURATION. -
Page 46: Single Arrhythmic (Sa)
Depress S1 PULSES, then MONOPHASIC. Depress TIMING DELAY and enter 00.000005 seconds. Depress TIMING DURATION, then enter 00.00200 seconds. Depress S2 FUNCTION, and select FUNCTION = SYNC TRAIN TO S1 (TS). Depress S2 PULSES, and select MONOPHASIC. Depress TIMING RATE, and enter 0010.00 PPS. Depress TIMING DELAY, and enter 00.00001 seconds. -
Page 47: S Ync To S2 D Elay
S2 D ync tO elay This mode is intended for applications when an external device is to be used to control the S2 output. The connection from the external device must connect to the S2 DELAY SYNC IN and be a positive 5 volts for triggering to occur. -
Page 48: Onophasic Ulse Ode
Using two SIUV units (Biphasic Constant Voltage) Connect one SIU-V to the S1 Output and a second SIU-V to the S2 Output. Select the SIU-V in the CHOOSE STIMULUS ISOLATION UNIT setup screen for both S1 and S2. Select Monophasic (MO) for the Pulses selection. Select the Sync with S1(SS) S2 Function and use the S2 Delay to separate the pulses. -
Page 49: Artifact, Stimulus Isolation & Constant Current
Artifact, Stimulus Isolation & Constant Current timulus rtifact When a stimulus pulse is introduced to a preparation to evoke a response, an electrical artifact appears in the recording instrumentation as the result of the spread of the stimulus current to the recording electrodes. This artifact precedes the evoked response in time as indicated in the oscilloscope record of Figure 8-1. -
Page 50: S Ources & R Eduction Of
& r ources eductioN of timulus rtifacts Excessive stimulus artifact results when the recording electrodes unavoidably measure the field distribution of the stimulus voltage through the preparation. The size of the stimulus and the proximity of the recording and stimulating electrode pairs contribute to the artifact amplitude. -
Page 51: S Timulus I Solation
timulus solatioN Warning: The S88X output is not isolated. Do not use on humans. Isolation of the signal from ground is most effective in the reduction of those artifacts due to ground currents arising from the stimulating and recording systems which are conductively joined by the preparation. When stimulus isolation is used during cortical stimulation, and in similar instances when a large volume of tissue surrounds closely spaced stimulating electrodes, the stimulus current sets up a three-dimensional... - Page 52 timulus urreNt oNitoriNg It is often desired to measure the actual stimulus current. There are two ways of measuring the stimulus current. A DC ammeter can be connected in series with the stimulating electrodes or an oscilloscope can be utilized. When using a milliammeter or microammeter, it should be placed in series with the stimulating electrodes.
- Page 53 Oscilloscope monitoring of instantaneous stimulus current can be accomplished by monitoring the voltages generated across a series resistor with an oscilloscope. Use a series resistor whose value is very small relative to that of the stimulating electrodes and construct a circuit as shown in Figure 8-4.
- Page 54 8-54 Chapter 8 Artifacts, Stimulus Isolation & Constant Current...
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Page 55: Troubleshooting & Maintenance
Troubleshooting & Maintenance General If the S88X display does not light up during power up, check to see that thepower cord is attached to the S88X and to a standard 3-wire AC receptacle. If it still will not power up, check the outlet to be sure there is power, by connecting another device to the outlet. -
Page 56: F Ield S Oftware U
ield oftWare Pgrade Field firmware changes can be made via the USB interface. Follow the steps below: Locate a Windows PC with USB 2.0 interface. Copy the S88Xusb.sys file (on distributed media) into the windows/system32/drivers directory. Turn on the S88X. When it is finished booting, connect the USB port on the rear panel of the S88X to the PC USB port. -
Page 57: Ppendix
Appendix Constant Voltage vs. Constant Current Sources for Pulse Stimulation While the principal factor responsible for electrical stimulation is current, the amount of voltage required to produce this current is a function of the impedance presented by the electrodes and the surrounding tissue. This varies widely. - Page 58 Everything is relative though, and ratio of source and load impedances (including the resistive and capacitive components) need to be evaluated for proper understanding of “Constant Voltage/Constant Current”. What is more important to recognize is that frequently the current or voltage that is measured in the lead wires is hardly the same as it appears at the interface of the tissue and electrode because of diffusion.
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Page 59: S88X Timing Diagrams
Appendix S88X Timing Diagrams Function = Single Pulse (SP) Sx = S1 or S2 Sx Delay Sync Out Pulse Duration Pulse Delay Function = Repeating Pulse (RP) Sx = S1 or S2 Sx Delay Sync Out Pulse Duration Pulse Delay Sx Rate B-59 S88X Dual Output Square Pulse Stimulator... - Page 60 Function = Single Train (ST) Sx = S1 or S2 Train Sync Out Rate Duration Sx Train Duration Sx Train Delay Sx Pulse Delay Function = Repetitive Train (RT) Sx = S1 or S2 Train Sync Out Rate Duration Sx Train Duration Sx Train Delay Sx Pulse Delay Sx Train Rate...
- Page 61 S1 Function = Ext Control from S1 Delay (SD) S1 Delay Sync Out Pulse Duration Pulse Delay S1 Delay Sync In S1 Function = Ext Control from Train Duration (TD) Train Delay Sync Out Rate Duration S1 Train Duration S1 Train Delay Train Duration Sync In S2 Function = Ext Control from S2 Delay (SD) S2 Delay Sync Out...
- Page 62 S2 Function = Sync with S1 (SS) S1 = Single, Repeating, or Trains S1 Delay Sync Out S1 Rate Duration Duration Delay S2 Function = Single Arrhythmic (SA) S1 = Repeating S1 Delay Sync Out S1 Rate Duration Delay Duration Delay B-62 Chapter B Appendix...
- Page 63 Function = Post S1 Train (PT) S1 = Single or Repeating Trains Train Sync Out Duration Train Duration Train Delay Duration Delay S2 Function = Sync Train to S1 (TS) S1 = Single or Repeating S1 Delay Sync Out S1 Rate Duration Delay Train Duration...
- Page 64 B-64 Chapter B Appendix...