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!
Bookmark not defined.
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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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Problem Solving
If the instrument appears to be not working properly, check all of the control settings
and connections. Be sure to wait at least 5- 10 seconds after turning the instrument off
before turning it on again. The following summary of typical problems for the user
(along with the most common solutions) may help:
Problem Cause/Solution
EVENT indicator never lights, even in
FREE RUN mode. • Replace fuse, check power connection
• Set DELAY or PERIOD to a shorter interval.
• Power-on too soon after power-off.
OVERLAP indicator is on. • Set DURATION >0.00.
• DURATION is set to SQUARE, but PERIOD is
0.00. Increase PERIOD or set DURATION
independently.
• BURST and WIDTH are > DURATION.
Increase PERIOD or decrease DURATION.
• BIPHASIC pulse output is on and PERIOD is
not longer than twice the DURATION.
Increase PERIOD or decrease DURATION.
• Free-run is on and BURST is < PERIOD
(BURST off), DELAY is 0 and PERIOD is <
DURATION. Add, delay or modify PERIOD.
• Free-run is on, BURST > DURATION,
PERIOD < DURATION. Increase PERIOD.
ERROR indicator is on. • For VOLTAGE outputs: the output is trying to
drive too low a resistance or capacitance (e.g.
a short circuit). Check by disconnecting the
output. It is possible that for the fastest cycles
and largest amplitudes (close to 100V and
1µs) that the ERROR indicator might always
come on during repetitive pulses. Fix output
load or decrease amplitude as required
.
Time appears to be excessive. • Changed control in mid-cycle, (resets current
status).
Can’t seem to get a full signal out. • Load is not properly connected, repair wiring.
Incoming triggers not accepted frequently
enough • PERIOD is set too long, (enforces “dead time”) followed by BURST set to SIGNAL. Reduce
.
Table 1.0 Problem Solving
If you suspect that the Model 2100 may have completely failed, we recommend
checking the basic level of functionality. If this fails, your instrument is defective and
must be repaired. If this passes, either your experimental setup is incompatible or
inconsistent; or there is a more subtle flaw in your Model 2100.
If the Model 2100 appears to be malfunctioning, contact A-M Systems, Inc., or your
dealer.

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Theory of Operation
The operation of the Model 2100 is summarized in the block diagram (see the figure on
Page 11). Not shown are all of the interconnections with the microcontroller. The
internal microcontroller plays an important role in setting the signal path, but does not
directly contribute to the dynamic characteristics. It scans the front panel switches,
and sets the control values for the logic arrays. It programs the internal counters,
which along with the other hardware achieve the necessary sub-microsecond speeds.
Pulse generation starts either from an input trigger signal (from Trig In), or an internally
signal (Free Run mode). A Delay timer counts the 10MHz clock until its count value is
exhausted. At this point, the Burst, Period, and Duration timers are started. If the
Burst timer has not expired by the end of the Period, the Period and Duration timers
are restarted. If the Biphasic mode has been set, the Duration timer is restarted at the
end of the initial Duration, and the sign of the output pulse is reversed, doubling the
total duration.
The system state (pulse on, pulse sign, baseline sign [+/0/-]) is transmitted to the
isolated section via optoisolator. The baseline and pulse amplitudes are selected by
an analog switch. The resulting signal is amplified by a variable-power-supply discrete
operational amplifier. The amplifier connections and gain is modified to provide two
voltage and three current ranges.
Timing overlap errors are detected by a logical decision computation rather than by
testing for counter collisions. This provides instant feedback, rather than waiting up to
an hour for such a collision to occur. Output errors are measured by sensing the
output amplifier’s differential input voltage. Under normal conditions, this is a negligible
voltage. If the amplifier fails to deliver the requested signal the window comparator
testing this voltage sends this message (via optoisolator) to the logic section, turning
on a warning LED.

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Specifications
There are three classes of specifications. Class A specifications tested in all units, and
are guaranteed. Class B specifications are inherent in the design; they are indirectly
tested and are guaranteed. Class C specifications are typical operating values which
are occasionally tested-, these are typical values, given for your information but not
guaranteed. The class for each specification is noted in the center column of the
following sections.
Inputs
Switching level
A
1.6 V (± 0.2 V)
Hysteresis
C approx. 50 mV
Input equivalent circuit C 100KΩ to +5 in parallel
with no more than 35pF
Minimum duration
(TTL-level signal) C > 50 ns.
Open circuit condition
Timing and rate accuracy
B defaults to high/on level
Rate selector steps B 100µs to 100s in 7 steps
Timing multiplier steps B 1% of rate selector step
size. Maximum value is
9.99 x the rate selector
step size
Resolution B approx. 0.1% of the maximum
value
Timing error (second and later B < 0.02% of rate selector value +
pulses after resetting controls) 0.15 µs
Timing error (first pulse after C an additional 0.25 µs error may
readjusting timing controls) occur
Timing repeatability C < 0.01% setting + 20 ns

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(monophasic)
TRIG IN to OUTPUT delay C approx. 0.5 µs for a load of no
(DELAY set to 0), output set to more than 10 KV in parallel with
2 V 50 pF
Timing jitter from TRIG IN to C < 125 ns (all rates except 100s)
OUTPUT (for TTL trigger input
with risetime <10 ns) < 1.25 µs (100s rate)
Timing jitter from TRIG OUT
(either BURST or PULSE) and
OUTPUT
C Less than 20 ns (all rates)
Trigger output to pulse output
delay
Output characteristics
C approx. 350 ns
Pulse level error (voltage mode:
A
< 0.3% of setting + 0.5% of r
open circuit; current mode: short range (plus an additional 0.5 µA
circuit in 100 µA range)
Biphasic level difference C < 0.3% of range (voltage
| V+ + V- | /2 modes: into open circuit;
current modes: into short circuit)
Baseline level error (voltage mode:
open circuit; current mode: short
circuit)
A
< 0.3% of setting of setting +
0.1% of range (plus an
additional 0.5 µA in 100µA
range)
Risetime (2.5 V out)
A
≈200 ns into less than 30 pF
Risetime (25 V out)
A
≈1.5 µs into less than 30 pF
Transient response
A
< 8% overshoot into less than
30 pF for pulse voltages
different than baseline voltage
by at least 10% of range
Output impedance (voltage mode) C ≈50 ohms
Output impedance (current mode) C >>10 GΩ(typically 200 GΩ)
Isolation resistance
A
>>100 MΩ

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Isolation capacitance C ≈ 60 pF at 100 Hz
Noise (differential mode) C ≈ 1 mV rms (10 V scale;
10 Hz - 4 MHz)
Noise (common mode: earth to C ≈ 8 mV rms (10 Hz - 4 MHz);
isolated ground) with no signal ≈ 100 mV p-p
output (200 Hz - 10 MHz), measured
with a 10 M
Ω, 15 pF
oscilloscope probe
Overload error indicator (low C
Turns on for set amplitude at or
frequency, short circuited voltage greater than approx. ±1 V (10 V
mode) range); or ±2 V (100 V range)
Overload error indicator low C
Turns on for set amplitude at or
frequency, open circuited current
mode) above approx. 2% of range
Overload error response time C Flat to approx. 30 µs duration
Decreasing sensitivity for
Miscellaneous
shorter pulses
Power
approx. 11 watts
Fuse
1 amp 3 AG
Operating temperature range
10 - 30° C
Storage temperature range
0 - 50° C
Operating humidity
5 - 80% RH
Dimensions 17 x 4.75 x 11.25 (inches)
43.2 x 12.1 x 28.6 cm
Weight 20 lbs (9 kg)

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Warranty and Service
LIMITED WARRANTY
What does this warranty cover?
A-M Systems, LLC (hereinafter, “A-M Systems”) warrants to the Purchaser that the Instruments manufactured by
A-M Systems (hereinafter the “hardware”), and sold after January 1, 2020, is free from defects in workmanship or
material under normal use and service for the lifetime of the hardware. Headstages manufactured by A-M Systems
and sold after January 1, 2020, will be repaired under warranty only once per year. This warranty commences on
the date of delivery of the hardware to the Purchaser. “Lifetime” is defined as the time all components in the
instrument can still be purchased from mainstream, common, electronic component distributors such as Digi-Key
Electronics, Newark, or Mouser Electronics.
For hardware sold prior to January 1, 2020, the warranty in effect at time of purchase applies, with the maximum
warranty period of three (3) years for new purchases, and one (1) year for those that have been repaired by A-M
Systems. For headstages manufactured by A-M Systems and sold prior to January 1, 2020, the maximum warranty
period is one (1) year.
What are the obligations of A-M Systems under this warranty?
During the warranty period, A-M Systems agrees to repair or replace, at its sole option, without charge to the
Purchaser, any defective component part of the hardware. To obtain warranty service, the Purchaser must return the
hardware to A-M Systems or an authorized A-M Systems distributor in an adequate shipping container. Any
postage, shipping and insurance charges incurred in shipping the hardware to A-M Systems must be prepaid by the
Purchaser, and all risk for the hardware shall remain with Purchaser until A-M Systems takes receipt of the
hardware. Upon receipt, A-M Systems will promptly repair or replace the defective unit and then return the
hardware (or its replacement) to the Purchaser with postage, shipping, and insurance prepaid by the Purchaser. A-M
Systems may use reconditioned or like-new parts or units at its sole option, when repairing any hardware. Repaired
products shall carry the same amount of outstanding warranty as from original purchase. Any claim under the
warranty must include a dated proof of purchase of the hardware covered by this warranty. In any event, A-M
Systems liability for defective hardware is limited to repairing or replacing the hardware.
What is not covered by this warranty?
This warranty is contingent upon proper use and maintenance of the hardware by the Purchaser and does not cover
batteries. Neglect, misuse whether intentional or otherwise, tampering with or altering the hardware, damage caused

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LIMITED WARRANTY, cont
by accident, damage caused by unusual physical, electrical, chemical, or electromechanical stress, damage caused
by failure of electrical power, or damage caused during transportation are not covered by this warranty. Further, no
guarantee is made regarding software compatibility with future updated operating systems. Products may not be
returned to A-M Systems for service, whether under warranty or otherwise, which are contaminated by infectious
agents, radioactive compounds or other materials constituting a health hazard to employees of A-M Systems
What are the limits of liability for A-M Systems under this warranty?
A-M Systems shall not be liable for loss of data, lost profits or savings, or any special, incidental, consequential,
indirect or other similar damages, whether arising from breach of contract, negligence, or other legal action, even if
the company or its agent has been advised of the possibility of such damages, or for any claim brought against you
by another party.
THIS EQUIPMENT IS NOT INTENDED FOR CLINICAL MEASUREMENTS USING HUMAN SUBJECTS.
A-M SYSTEMS DOES NOT ASSUME RESPONSIBILITY FOR INJURY OR DAMAGE DUE TO MISUSE OF
THIS EQUIPMENT.
Jurisdictions vary with regard to the enforceability of provisions excluding or limiting liability for incidental or
consequential damages. Check the provision of your local jurisdiction to find out whether the above exclusion
applies to you.
This warranty allocates risks of product failure between the Purchaser and A-M Systems. A-M Systems hardware
pricing reflects this allocation of risk and the limitations of liability contained in this warranty. The agents,
employees, distributors, and dealers of A-M Systems are not authorized to make modifications to this warranty, or
additional warranties binding on the company. Accordingly, additional statements such as dealer advertising or
presentations, whether oral or written, do not constitute warranties by A-M Systems and should not be relied upon.
This warranty gives you specific legal rights. You may also have other rights which vary from one jurisdiction to
another.
THE WARRANTY AND REMEDY PROVIDED ABOVE IS IN LIEU OF ALL OTHER
WARRANTIES AND REMEDIES, WHETHER EXPRESS OR IMPLIED. A-M
SYSTEMS DISCLAIMS THE WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR USE, WITHOUT LIMITATION.

A-M Systems Model 2100 Manual DRW-5027100 rev 12
Revision History
Rev Date Description
76/30/06 Initial Document Control release
84/28/10 DCR201200 Warranty and company name
92/10/16 DCR 202466. Remove Calibration Instructions
11 1/18/19 DCR 202615. Review content. Correct rev, Add rev control to content
12 3/19/20 DCR 203316. Update Warranty