A-MSystems 2100 User manual

INSTRUCTION MANUAL
FOR
ISOLATED PULSE STIMULATOR
MODEL 2100
Serial #__________
Date____________
A-M Systems
PO Box 850
Carlsborg, WA 98324
U.S.A.
360-683-8300 ♦800-426-
1306 FAX: [phone]
http://www.a-msystems.com
Version 12.0
March 2020

Contents
General Description …………………………………………………………………….1
Instrument Features ……………………………………………………………………1
Controls and Connectors …………………………………………………………………2
Operating Instructions……………………………………………………………………..6
Theory of Operation…………………………………………………………………….9
Specifications…………………………………………………………………………...11
Warranty and Service……………………………………………………………….Error!
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Each Isolated Pulse Stimulator is delivered complete with:
Rack Mount Hardware
NOTE
This instrument is not intended for clinical measurements using human
subjects. A-M Systems does not assume responsibility for injury or
damage due to the misuse of this instrument.

A-M Systems 131 Business Park Loop, P.O. Box 850 Carlsborg, WA 98324
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Telephone: [phone] * 360-683-8300 * FAX: [phone]
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General Description
Instrument Features
The Isolated Pulse Stimulator Model 2100 is designed for a wide variety of applications.
It is highly flexible, being capable of delivering single pulses, biphasic pairs, or bursts of
pulses. Pulses may be started manually or upon receiving a trigger signal from another
instrument or computer. Two non-isolated trigger outputs are available for triggering
other instruments.
Four sets of timing controls provide comprehensive control over all aspects of pulse
generation. Three digit accuracy is available over a 7 decade range for each timing
function, using lever wheel switches. Pulse widths can be set over more than a 9
decade range, from 0.5 µs to 999 seconds. Timing accuracy is assured through the
use of a 10 MHz base rate crystal-controlled clock, digitally divided to provide accurate
timing over the entire range. A timing overlap indicator will light if the timing controls
are set inconsistently.
The output may be conveniently switched between current and voltage modes. Pulse
and baseline amplitudes are independently settable with lockable dials. An error
indicator will light if the Model 2100 cannot deliver the desired signal.
WARNING
The Model 2100 can produce potentially dangerous voltages up to 100 V at the output
connectors. The isolated output is not connected internally to safety (earth) ground in any
way. Some part of the external circuit should be connected to safety ground. Use caution in
handling any wires, connectors, or electrodes which may be directly or indirectly attached to
the Model 2100 output. Some kinds of connectors such as BNC connectors have exposed
metal parts which may float at dangerous potentials unless externally connected to safety
ground. For greatest safety, turn the Model 2100 off before making any connections to
the instrument.

A-M Systems 131 Business Park Loop, P.O. Box 850 Carlsborg, WA 98324
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Telephone: [phone] * 360-683-8300 * FAX: [phone]
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Controls and Connectors
The controls for the Model 2100 are grouped in three sections: START, which controls
when a pulse or burst of pulses begins; TIMING, which controls the on/off timing of one
or more pulses; and OUTPUT, which controls the amplitude of the output signal.
Start
TRIG SLOPE: Determines the polarity of valid trigger pulses
(positive or negative edges in the trigger signal).
MODE: Controls waveform initiation. When set to FREE RUN,
one timing cycle immediately follows the last. When
momentarily placed in the MANUAL position, a timing cycle
starts immediately. When the switch is in the center
position, timing cycles start when valid triggering events
occur.
TRIG’D: This LED lights up when a timing cycle is in process
and continues until the burst is completed.
TRIG: This BNC connector allows a signal from an external
source to initiate timing cycles. It is set for standard TTL
levels.
GATE: This BNC connector allows a signal from an external source to restrict the final
output signal. This input must be at a logical high (or open-circuited) in order for the
Model 2100 to recognize either manual or automatic trigger events.
Valid triggers (represented by the arrows in the figure) can occur only when the gate
is at logical high. Note that the up arrow would apply only if TRIG SLOPE is set to +;
the down arrows would apply only if TRIG SLOPE is set to -.
Note: Triggers have no effect if the system has not completed its response to a
previous trigger.

A-M Systems 131 Business Park Loop, P.O. Box 850 Carlsborg, WA 98324
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Telephone: [phone] * 360-683-8300 * FAX: [phone]
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Timing
Four sets of controls govern the timing of
pulse generation. Each set contains two
values which are multiplied together to
determine the actual timing value. The rotary
knob (rate selector) provides the approximate
timing value and the lever wheel switch bank
(MULTIPLIER) provides a time resolution of
three decimal digits. The following diagram
shows most of the important relationships.
DELAY: These controls determine the time duration between the initiating trigger
event and the beginning of the pulse burst. If this rate selector is set to NONE or the
multiplier is set to 0.00 there is no delay.
BURST WIDTH: These controls determine the time period in which one or more pulses
may be delivered. Once started a pulse may outlast the burst width. If this rate
selector is set to SINGLE, or to any time shorter than the pulse duration, only a single
pulse will occur. If the BURST WIDTH is longer than the period, pulses will be emitted at
the PERIOD rate until the burst time ends. Pulses are never truncated by a short BURST
WIDTH.
DURATION: These controls determine the
length of each pulse. If this rate selector is set
to SQUARE, the duration is set to half of the
period, regardless of the MULTIPLIER setting.
PERIOD: These controls set the period of time
between adjacent pulse events within the
burst. It also forces a minimum “dead time”
between recognized input triggers following
a burst of one or more pulses. This can be used to prevent over stimulation of a tissue
without requiring excessive delay between the triggering event and the stimulating
pulse.

A-M Systems 131 Business Park Loop, P.O. Box 850 Carlsborg, WA 98324
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Telephone: [phone] * 360-683-8300 * FAX: [phone]
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NOTE: If any of these timing controls are changed while a timing cycle is in operation, the
results are undefined until the current cycle finishes.
TIMING OVERLAP: This LED will light to indicate an
inconsistency in the timing cycle settings. There are several
ways to introduce such errors. The most common way is to
set the inter-pulse PERIOD to be less than the pulse
DURATION.
TRIG OUT (UPPER): This BNC connector provides a signal
which is coincident with the internal Burst timing signal
(default). This means the signal starts at the end of the
Delay time, and persists until the Burst time expires. This
output may also be set to represent the delay time-out by
setting the internal jumper J510 to the right two pins instead
of the left two pins (Please see the Calibration section in
this manual for jumper location; Directions are given as
viewed from the front of the instrument).
TRIG OUT (LOWER): This BNC connector provides a signal which is coincident with the
Duration timing signal which controls pulse output.
NOTE: Both trigger output signals slightly lead the isolated output signal.
Output
PULSE SIGN: This switch determines the
polarity of the pulses to be generated. It also
allows generation of biphasic pulses, thereby
doubling the effective total period. Warning:
the first pulse generated after changing the PULSE
SIGN switch may have the wrong polarity.
BASELINE: This switch determines the polarity
of the baseline signal.
RANGE: This rotary switch determines if the
output pulses will be constant current (3
ranges) or constant voltage (2 ranges).
BASELINE AMPLITUDE: This value is independently set using a ten-turn counting dial.
The maximum baseline amplitude is one tenth the value shown on the range amplitude
switch
PULSE AMPLITUDE: This value is independently set using a ten-turn counting dial. The
maximum pulse amplitude is the value shown on the range amplitude switch.

A-M Systems 131 Business Park Loop, P.O. Box 850 Carlsborg, WA 98324
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Telephone: [phone] * 360-683-8300 * FAX: [phone]
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EVENT: This LED indicates when a pulse is ongoing.
ERROR: This LED indicates when the internal output amplifier cannot output the pulse
as desired. This is usually due to a short circuit while trying to output a voltage, or an
open circuit while trying to output a current.
NOTE: The Pulse Sign control in the Output section directly affects waveform timing.
When set to the Biphasic mode, a positive-going pulse is immediately followed by a
negative-going pulse. This effectively doubles the pulse “duration”. If a burst of
biphasic pulses is being produced the period must be at least twice the single pulse
duration. In the Square wave mode, the baseline disappears as long as the burst
persists.

A-M Systems 131 Business Park Loop, P.O. Box 850 Carlsborg, WA 98324
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Telephone: [phone] * 360-683-8300 * FAX: [phone]
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Operating Instructions
Examples
Simple setup (and minimal instrument test)
Connect the output of the Model 2100 to an oscilloscope. Before connecting the Model
2100 to any other instrument, or the experimental preparation, it is safest to turn its
power off.
Set the Output controls:
Range: 10V
Pulse Sign: +
Baseline: Zero
Pulse Amplitude: 2.00
Setting The Timing Controls:
Delay: none
Burst Width: single
Duration: 1.50 * 10-2
Period: 5.00 * 10-2
Setting The Start Controls:
Mode: Free Run
Disconnect any cables to the TRIG or GATE inputs.
Note that the green Trig and Event indicators turn on as Free Run is turned on (and
turn off otherwise). You should observe a 15ms duration, 20Hz rate pulse. of 2.00V
above a 0V baseline on the oscilloscope.

A-M Systems 131 Business Park Loop, P.O. Box 850 Carlsborg, WA 98324
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Telephone: [phone] * 360-683-8300 * FAX: [phone]
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Demonstration of Burst Mode
Connect the output of the Model 2100 to an oscilloscope. Before connecting the Model
2100 to any other instrument, or the experimental preparation, it is safest to turn its
power off.
Set the Output controls:
Range: 10V
Pulse Sign: +
Baseline: -
Pulse Amplitude: 2.00
Baseline Amplitude 1.00
Setting The Timing Controls:
Delay: 8.80 * 10-2
Burst Width: 1.20 * 10-2
Duration: 1.50 * 10-2
Period: 5.00 * 10-2
Set the START controls as follows:
Mode: Free Run
Disconnect any cables to the TRIG or GATE inputs.
Trigger the oscilloscope from the Burst trigger out (upper Trig Out connector) for a
stable display. In each burst (occurring every l00ms), you should observe a trio of
15ms duration starting 50ms apart. Try switching the Start/Mode from Free Run to the
center (normal) position. The pulses will no longer be produced, and the Trig and
Event indicators will turn off. Pressing this switch once (to Manual) will cause a single
burst to occur.