S48 Users Manual Release B Sept 2006

© Copyright 2011

Astro-Med, Inc.

This manual is copyrighted with all rights reserved. No part of this manual may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language in any form by any means without written permission of Grass Technologies, An Astro-Med, Inc. Subsidiary. Information in this document is subject to change without notice. Astro-Med, Inc. assumes no responsibility for any errors, omissions or inaccuracies whatsoever.

Trademarks AURA®, Beehive™, Comet®, EC2®, Panorama®, SleepTrek®, SzAC®, TWin® and TWinLOOK® are trademarks of Astro-Med, Inc. Other brand and product names are trademarks or registered trademarks of their representative holders.

Stimulator Identification Data Congratulations. Your Grass purchase is an investment in the finest of state-of-the-art medical technology. The information provided below lists the model number and serial number of your Stimulator. If, for any reason, it should be necessary for you to contact Astro–Med, Inc. regarding your purchase, please refer to the following: Model Number:______________________ Serial Number:______________________

Printed in the United States of America

Important 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. This product must be cleaned and checked periodically. Do not use a defective product. Parts that are broken, missing, worn, or contaminated should be replaced immediately. If repair or replacement becomes necessary, call or write to request service advice from Grass. This product must not be altered without the prior written approval of Grass. The user of this product shall have the sole responsibility for any malfunction that results from improper use, faulty maintenance, improper repair, unauthorized service, or alteration by anyone other than Grass. The safety, reliability, and performance of this device can only be assured under the following conditions: • If the device has been used according to the accompanying operating instructions. • If changes or repairs have been carried out by Grass. • If it is used in buildings having ground equalization wiring that complies with relevant UL, CSA, IEC or other local standards and regulations.

Intended Use The S48 Stimulator is a general purpose, electrical stimulator for nerve and muscle that has a wide range of parameters to satisfy a wide range of research applications. The various Stimulus Isolation Units and Constant Current Units are parts of the Stimulator system. FOR USE BY QUALIFIED PERSONS ONLY. NOT INTENDED FOR THERAPEUTIC PURPOSES.

Warnings READ THIS BEFORE OPERATING S48 The available voltage and current from this Stimulator may, under some conditions, be sufficient to be lethal or cause burns, particularly with high duration and/or high voltage settings. It is the responsibility of the investigator/user, to determine for any given application, the maximum safe levels of stimulation, and assure that such stimulation levels will not be exceeded. In many applications, the mechanisms of safe stimulation are not completely understood. Parameters that affect safe stimulation levels are: • Pulse Repetition Rate • Pulse Duration • Pulse Duty Cycle • Voltage and/or Current Intensity • Biphasic vs Monophasic Operation • Total Time Exposure • Electrode Impedance, Geometry, Area and Material The S48 OUTPUT is NOT ISOLATED. Do not use on humans. CONSULT GRASS TECHNOLOGIES PRODUCT GROUP, ASTRO-MED, INC. IF YOU HAVE ANY CONCERNS ABOUT SAFE APPLICATION, PARTICULARLY WHEN USED WITH OTHER EQUIPMENT. GRASS TECHNOLOGIES PRODUCT GROUP, ASTRO-MED, INC. 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 IMPROPER USE AND/OR ABUSE OF THIS STIMULATOR.

Regulatory The S48 is ETL listed, conforms to UL Standard 3101-1 for Electrical Equipment for Laboratory Use, and is certified to Canadian Standards Association (CSA) C22.2 No. 1010‑1. The S88 also meets the requirements of the European Community Standard IEC‑1010-1. The various Stimulus Isolation Units and Constant Current Units are parts of the Stimulator system.

DECLARATION OF CONFORMITY Declaration de Conformité Ubereinstimmungserklärung Dichiarazione di Conformità Model No. Modele No. Model Nr. Modello No.

S48/S88

Type of Equipment Type d’ equipement Beschreibung des Gerates Tipo di apparecchio

Research Stimulator

Standards to which conformity is declared Standards auquel la conformité appartient Normen für welche Übereinstimmung erklärt wird Norme per le quali si dichiara la conformità

EN61010-1 EN55011

EN50082-1

Application of Council Directives Application des Decisions du Conseil Anwendbar fur die Richtlinien Applicazione delle Direttive del Comitato

73/23/EEC

89/336/EEC

Manufacturer’s Address Nom du fabricant Hersteller Nome del costruttore

Grass Technologies, An Astro-Med, Inc. Subsidiary 53 Airport Park Drive Rockland, MA 02370 Tel 781-792-3800 Fax 781-792-3823

The Technical construction file is located at:

Grass Technologies, An Astro-Med, Inc. Subsidiary 600 East Greenwich Avenue West Warwick, RI USA 02893 Tel 401-828-4000 Fax 401-822-2430

The authorized representitive located within the European Community is:

Xavier Berthe 1, rue Edouard Branly 78190 Trappes, France Tel (1)34.82.09.00 Fax (1)34.82.05.71

I, the undersigned, hereby declare that the equipment specified above conforms to the above Directive and Standard. Je, Soussigné, déclare que l’équipment spécifié ci-dessus est en conformité avec la directive et le standard ci-dessus. Ich, der unterzeichnende erkläre hiermit, daß das oben beschriebene Gerät den vorgenannten Richtlinien und Normen entspricht. Il sottoscritto dichiara che l’apparecchio sopra specificato è conforme alle Direttive e Norme.

(signature of authorized person)

Date of issue: 9/20/06

Table of Contents 1. S48 Specifications...1-11 2. Introduction. ... 2-13 Description... 2-13 Safety Information... 2-13 3. General Features... 3-15 Applications & Capabilities. ... 3-15 Accuracy & Waveform... 3-17 Line Voltage Requirements. ... 3-18 Duty Cycle... 3-19 4. Description of Circuits... 4-21 Power Supplies... 4-21 Stim &Train Rate... 4-22 Delay, Duration & Train Duration. ... 4-22 Volts. ... 4-23 5. Operational Controls... 5-25 Power & Output. ... 5-25 Stim Mode Switch & Twin Pulses Switch. ... 5-27 Train Mode. ... 5-27 Train Rate Controls... 5-28 Train Duration Controls... 5-29 Stim Rate Controls... 5-30 Delay Controls. ... 5-31 Duration Controls. ... 5-32 Volts Controls... 5-32 6. Synchronous Inputs & Outputs... 6-35 Synchronous Inputs. ... 6-35 Synchronous Outputs... 6-38 Modulate Input (Mod In)... 6-41 External Control. ... 6-42 External Voltage Control of Stim Rate & Train Rate... 6-43

S48 Square Pulse Stimulator

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7. Modes of Operation. ... 7-45 Single or Repititive Pulses... 7-45 Twin Pulses (Alike)... 7-46 Mixing the Outputs of Two Stimulators. ... 7-48 Trains of Pulses (Single or Repetitive)... 7-49 Pairs of Repetitive Unlike Pulses Using Two S48 Stimulators and Two SIUs... 7-51 External Control via Sync In. ... 7-54 8. Artifacts, Stimulus Isolation, Constant Current & Mixing. ... 8-55 Stimulus Artifact. ... 8-55 Sources & Reduction of Stimulus Artifacts... 8-56 Stimulus Isolation... 8-57 Stimulus Current Monitoring... 8-58 Constant Current Output from the S48... 8-60 Constant Current with the CCU1 without Ground Isolation... 8-61 Constant Current & Stimulus Isolation with the SIU5... 8-62 Constant Current with the PSIU6 (not for use on humans)... 8-62 Mixing S1 & S2 Outputs through Two SIU5s to get True Addition and/or Biphasic Waveform. ... 8-63 9. Troubleshooting & Maintenance... 9-65 General. ... 9-65 Overload Reset Circuitry... 9-65 Procedure... 9-66 10. Appendix... 10-67 Constant Voltage vs. Constant Current Sources for Pulse Stimulation. ... 10-67 References. ... 10-69 Service Policy Warranty

x

Table of Contents

1

S48 Specifications

Train Rate ������������������� 1/100 sec to 100 TPS (4 decades); single or repetitive Train Duration ��������������� 1 msec to 10 sec (4 decades) Stimulus Rate ��������������� 1/100 sec to 10 sec (5 decades); single or repetitive Pulse Delay ����������������� 10 µsec to 10 sec (6 decades) Pulse Duration �������������� 10 µsec to 10 sec (6 decades) Synchronous Outputs (TTL) �� STIM, DELAY, TRAIN; Front Panel: 10 µsec, 50 Ω; Rear Panel: 1 or 10 msec and TRAIN END Synchronous Inputs (TTL) ���� STIM, DELAY, TRAIN DURATION; Trigger from rising or falling edge Rear Connector (DB25S) ����� All SYNC INPUTS and OUTPUTS; External Analog Timing Control Volts Out �������������������� 10 mV to 150 V (5 decades) Peak Output Current ��������� 150 mA with 1000 Ω load Output Impedance ����������� 250 Ω nominal on all voltage ranges; 25 Ω and 100 kΩ on highest range AC Power ������������������� 115/230 V, 50/60 Hz, 125 watts peak, 20 watts standby Physical Size ���������������� 17.25” W x 5.25” H x 12.5” D (43.8 cm x 13.3 cm x 31.8 cm) 19” (48.3 cm) rackmount brackets supplied Weight: 14 lbs., 2 ozs. (2.4 kg)

S48 Square Pulse Stimulator

1-11

1-12

Chapter 1 Specifications

2

Introduction

Description The S48 is a dual-channel, general purpose stimulator for nerve and muscle stimulation procedures. Applications extend from single cell to entire muscle stimulation. The two output channels can be operated independently or synchronized to produce complex paradigms. The outputs are non-isolated constant voltage positive pulses. New features include computer compatibility and flexibility of synchronization circuits. The synchronous inputs and outputs are TTL, 5 volts, PC compatible. A rear DB25S connector permits external analog control of the timing circuits. Optional Grass Stimulus Isolation Units are available for applications requiring isolation and/or constant current.

Safety Information CAUTION

Misuse of this product may constitute a safety hazard. Please review the following.

WARNING

The S48 output is not isolated. Do not use on humans.

1.

For use by qualified persons only.

2.

Removal of the S48 Stimulator top cover may expose you to lethal voltages and other hazards. Observe labels and caution notices.

S48 Square Pulse Stimulator

2-13

3.

Never drop or push objects into the stimulator through cabinet slots, as it is possible to come in contact with hazardous voltages or cause damage.

4.

If the cabinet is damaged, a shock hazard may exist. Unplug the stimulator and have it checked by a qualified person or contact Grass Technologies.

5.

Never expose the stimulator to rain or moisture as this can be a potential cause of fire or shock hazard. If the S48 is exposed to moisture, unplug it and have it checked by a qualified person.

6.

The S48 cabinet has slots or louvers for ventilation purposes to prevent component overheating. a. Never cover the slots or louvers with cloth or any other material. b. Avoid placing the S48 over radiators or heat registers. c. Never place the stimulator in an enclosure unless proper ventilation is provided and all other related precautions taken.

2-14

7.

Operate the S48 only on the power sources as printed on the panel. Damage may result from incorrect voltage.

8.

The voltage/current output of this general purpose stimulator can be lethal or cause tissue damage if not used properly by persons trained in the application intended for this instrument.

9.

Note the output of this general purpose stimulator is referenced to ground, i.e., one terminal of the output is ground. Also all sync inputs and outputs are also referenced to ground. To obtain stimulus potentials isolated from ground choose the appropriate Grass isolation unit.

10.

If this stimulator is to be used with an isolation output, use the proper Grass isolation unit accessory. Contact Grass Technologies for application information in writing.

11.

Determination of the safe levels of the stimulation for each application is the responsibility of the investigator in charge.

12.

The investigator in charge is responsible for assuring safe stimulation levels will not be exceeded.

Chapter 2 Introduction

3

General Features

Applications & Capabilities The S48 Square Pulse Electrical Stimulator has six continuously variable parameters which can be set to deliver single, repetitive, twin pulses, trains of pulses and trains of twin pulses from its single output. The constant voltage output is a positive, nonisolated voltage from a low impedance source and must be used with a companion stimulus isolation unit if isolated stimuli are required. Several models of stimulus isolation units, both constant voltage and constant current types are available. The S48 synchronous inputs and outputs and external control circuits have been carefully designed to provide the optimum synchronization and control characteristics when interfacing other peripheral instrumentation such as PC based acquisition systems, oscilloscopes, analyzers, etc. In addition to the individual front panel connectors, a multi-terminal rear panel control connector is supplied for convenient cabling. The S48 is intended for nerve and muscle stimulation procedures with applications extending from single cell stimulation to entire muscle. The output circuit is capable of delivering appreciable power, especially when the S48 is used without a stimulus isolation unit. Some procedures such as field stimulation require considerable stimulus current, unobtainable from any stimulus isolation unit. The S48 has a FAIL-SAFE shut-down circuit that limits output current and prevents component damage in response to overload or accidental short circuiting of the output. The S48 is supplied as a table-top unit and contains a tilt bail. However, rackmounting at standard 19” (48.3 cm) is possible using the rackmount brackets supplied with the S48.

S48 Square Pulse Stimulator

3-15

The S48 is a general purpose Stimulator and is not intended for use on humans. The S48 is ETL listed. conforms to UL Standard 3101-1 for Electrical Equipment for Laboratory Use, and is certified to Canadian Standards Association (CSA) C22.2 No. 1010-1. The S48 also meets the requirements of the European Community Standard IEC-1010-1 The S48 cannot deliver a true symmetrical biphasic pulse which is equal in positive and negative amplitudes and duration. However, if a Model SIU5 Stimulus Isolation Unit is used with the S48, a biphasic waveform can be produced which, although not symmetrical, does have a negative and positive component which is equal in effective energy (////// area under the curve) in terms of coulombs, if averaged over a sufficiently long period of time. It is possible to obtain a true symmetrical biphasic pulse by mixing the output pulses from two S48 Stimulators through two stimulus isolation units. See Chapter 8, Mixing S1 and S2 Outputs through Two SIU5s to get True Addition and/or Biphasic Waveform. Although the output of the S48 is constant voltage, it is possible to switch in a 100 kilohm resistor in the X10 (100kΩ) position of the VOLTS multiplier switch to obtain a 0.1 milliampere to 1.5 milliamperes (maximum) constant current output. See Chapter 5, Volts Controls.

Figure 3-1a: Monophasic Waveform

Figure 3-1b: True Biphasic Waveform

Figure 3-1c: Effective Biphasic Waveform

The S48 is compatible with all Grass Stimulators and Stimulator accessories, the SIU5, PSIU6, SIU7 and SIU8T Stimulus Isolation Units and the CCU1 Constant Current Unit.

3-16

Chapter 3 General Considerations

Accuracy & Waveform All S48 timing parameters are accurate to within ±5%. The “open circuit” output voltage is also accurate to within the same tolerance. However, when driving low impedance preparations from the S48, the actual voltage delivered to the preparation will differ from the dial setting due to “loading” of the S48 output. There is absolute independence of the parameters when the duty cycle of both the DELAY and DURATION circuits is less than 50%. Both the rise and fall times of the S48 output pulse are approximately 1.5 µs on all voltage ranges. Calibration of the duration is based on the average width of the pulse. Figure 3-2 is a diagram of the pulse waveform at a duration of 10 µs pulse at 1000 PPS (pulses per second), and 150 volts.

Figure 3-2: Pulse Waveform

Because of this high accuracy, it is seldom necessary to monitor the stimulus. However, if complex waveforms are utilized, especially as generated from two stimulators, or until single stimulator operation is understood, monitoring the output with an oscilloscope is advised. (See Chapter 8, Stimulus Current Monitoring.) Some typical pulse patterns from one or more S48s is shown in Figure 3-3.

Figure 3-3: Typical Stimulus Waveforms

S48 Square Pulse Stimulator

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Line Voltage Requirements The S48 AC power inlet includes a combination fuse block and line voltage selector. The current line voltage selection is indicated in a small window in the fuse block (115 or 230). To change the selection, first remove the AC line cord. Then, using a small bladed screwdriver, release the fuse block latch.

Figure 3-4: Combination AC Power Inlet, Fuse Block, Line Voltage Selector

Remove the fuse block from the receptacle. Remove the line voltage selector by pulling it straight out and/or prying gently with a small screwdriver. Rotate the line voltage selector until the correct selection appears (115 or 230) and push back into the receptacle firmly. Load the fuse block with the correct type and rating of fuse (see rear panel fuse label). Replace the fuse block, pushing firmly until it seats and latches. Verify that the correct voltage selection appears in the small window in the fuse block. Replace the AC line cord.

Figure 3-5: Switching from 115- to 230-volt Operation

3-18

Chapter 3 General Considerations

Duty Cycle Duty cycle is defined as the ratio of the time that the stimulus is “ON” to the total period or interval. 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 (T=1/F), the DELAY and DURATION controls should not be set greater than T=1/2F which is equivalent to 50% duty cycle. 100% duty cycle occurs when a circuit is “on” continuously, as with DC. Example: 50% duty cycle occurs if there is “on-off” symmetry, as with a symmetrical square wave, where the “on” time (or pulse duration) is equal to the “off” time (or time between pulses) for one cycle. See Figure 3-6.

Figure 3-6: 50% Duty Cycle

Since the maximum frequency selectable with the STIM RATE circuit is 1000 Hz, having a period of 1 millisecond, setting the DELAY and DURATION controls to less than 0.5 milliseconds (500 microseconds) will insure that 50% duty cycle will not be exceeded. If the DELAY circuit is not being used, simply set the DELAY controls for less than 500 microseconds. (Set DELAY multiplier to X.01.) It is important to note that duty cycles greater than 50% are seldom used in physiological stimulation procedures. Most triggerable circuits, such as those used in the S48, cannot be driven satisfactorily over 90% of their duty cycle. Although there is no possibility of circuit component damage when operating at duty cycles greater than 50%, the calibration may be affected.

S48 Square Pulse Stimulator

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3-20

Chapter 3 General Considerations

4

Description of Circuits

Power Supply The S48 power supply provides highly regulated DC voltages for circuit operation. The following voltages are generated: +175 volts DC for output circuits +5 volts DC for timing circuits +12 volts DC for timing circuits -12 volts DC for timing circuits

Figure 4-1: S48 Power Supply

S48 Square Pulse Stimulator

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Stim & Train Rate The STIM and TRAIN RATE circuits are free running oscillators with the MODE switch in the REPEAT position. These circuits will oscillate continuously when in the REPEAT mode. The TRAIN RATE frequency (TPS or trains per second) covers a range of 0.01 to 100 trains per second. The STIM RATE frequency has a range of 0.01 to 1000 PPS (pulses per second). The dials span a range of 1 to 10 and are continuously variable. The multiplier switches located below the dials provide decade range changes. The combination of the two controls sets the frequency.

Delay, Duration & Train Duration The DELAY, DURATION and TRAIN DURATION circuits are monostable circuits or “one-shot” circuits that must be enabled or triggered into operation. In response to a short positive pulse, these circuits are triggered out of their stable state. The time required for the circuit to return to its stable state determines the delay or duration and is controlled by the DELAY and DURATION settings. Both delay and duration parameters have a very wide range - from 10 microseconds to 10 seconds in six ranges. The TRAIN DURATION has a range of 1 millisecond to 1 second in four ranges.

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Chapter 4 Description of Circuits