7000 Analog/Hybrid Computing System
teaturing
MICROPATCH
wort aruacletle |
DIGITAL COMPUTER CONTROLLED 4
ELECTRONICALLY PROGRAMMED
ANALOG/HYBRID COMPUTER.
COMDYNA, Inc.
COMPUTERS FOR DYNAMIC ANALYSIS
700.
i
A HYBRID COMPUTER i
A DIGITAL COMPUTER PERIPHERAL ©
A SMALL PROCESSOR
A LARGE SIMULATOR
The 7000 Building Block Analog/Hybrid Computing Sy
computing units, accessories and interface networks that may be configured to meet
isan
small, medium or large simulation requirements.
A schematic of the 7000 organization is shown below...
ACCESSORIES
7979
INTERFACE
NETWORK
EXTERNAL
DIGITAL
COMPUTER
7091 or 7093
ANALOG/ DIGITAL
CONVERTER
POWER SUPPLY
7986
CONTROL UNIT
blage of analog
Analog Computing Units . . . The
programmed Micropatch and the patch cord pro-
grammed GP-10 analog computing units plus a
wide assortment of computing components offer
a versatile choice of Bnelog computer operations.
Performance,
iences are cost-benefit determinations as pros-
pective users may custom select the pert imi of
g units, op-
erating features. Following installation, ri 7000
system may be expanded, contracted or upgrad-
ed by the addition, deletion or exchange of com-
puting units and internal components.
Interface .. . An internal bus structure organizes
into single operating systems the analog comput-
ing units, desk top control module, analog/digital
and digital/analog converters and an external
digital computer. The 7000 system fi an all
isplays; digital and display of the com-
pute time period; a lamp indicator of amplifier
overrange; a digital voltmeter for measurement
of coefficient gs or
outputs.
Analog/Digital & Digital/Analog Conversion . . .
Within a 7000 system are analog to digital and
digital to analog convertors that are interfaced to
the host digital computer via a bi-directional data
bus. All analog variables may be accessed efor
digital p as the
work is. the ADC multiplexer, Multiplying digital
to analog convertors, located within the analog
computing units, provide analog computer pro-
cessing of digital variables. In addition to the
MDAC’s, a central digital/analog converter is
available to transmit digital computer generated
electronic
tor mode control and time scaling, digital volt-
meter or digital computer set of coefficient at-
tenuators and a digital computer I/O port.
Operator Control and Monitor . . . A desk top con-
trol unit serves the 7000 system as a centralized
base of operations. Operator features include a
push button slow time and high speed icpetitive:
operation mode control with LED
External Digital Computer . . . A twenty four bit
parallel data bus and ribbon cable connector ter-
minations are easily used with standard digital
computer input/output ports. Digital information
is transfered as analog variables and as control
states. A 7000 system may be operated by the
host solely as a i peripheral,
or it may be operated as a hybrid computer where
‘ion control is shared with the desk top
two axis electronic address with vSigital Tocation
control module.
Micropatch, centerpiece of the new 7000 Building Block Analog/
Hybrid C i y pl. i panels and patch
cords with a digital computer controlled electronic switch network.
Once progr: d, Micropatch operates i ically to traditional
patch panel computers. Through a host digital computer, simula-
tions are programmed directly from differential equation statements.
From digital computer memory, stored simulation programs are in-
stantly recalled for immediate use.
MICROPATCH
ANALOG COMPUTER PROGRAMMING THROUGH DIGITAL COMPUTER SOFTWARE
Micropatch operates essentially as a digital computer peripheral. The electronic switch organization is adapta-
ble to standard digital computer |/O buses. Coding is easily formatted and implemented with common high
level languages such as BASIC, PASCAL and FORTRAN. Memory requirements are modest. Complex, high order,
non-linear simulations are generated with less than a hundred bytes of usuable memory.
Micropatch software enhances the use of analog computer simulation in two principle ways.
1. Program Development . . . Micropatch is a digital Pp aid that eliminates the tedious
scaling, patching and checkout of analog computer programs. Through a keyboard/CRT, the micro-
patch programmer directly enters equations and system parameters. The digital computer formats equa-
tions into micropatch programming codes, scales variables, computes coefficients, outputs to micro-
patch the programming enters and finally performs a checkout routine. The
micropatch user, within after equation entry, is pi an analog simulation model that is
ready for experimentation and analysis.
2. Program Storage. . . C i i rogram storage enhances the application of
analog simulation models. Once a model is digitally formatted it may be indefinitely stored. A virtual
limitless number of analog computer models may be digitally stored and ilable for ii di. use. An
icati library a live i i i are perpetually on-call. On-call simu-
lations offer particularly strong benefits for the following application areas:
Teaching . . . One micropatch computing unit, through
program recall, is a potential simulator of many physical
systems. Student experiments benefit from powerful digital
computer graphics and the unique realism of analog com-
puter simulations. Simulations are instantly available to
support a wide range of engineering and scientific educa-
tional programs.
Math Model Development . . . Analog models are derived
with the help of hands-on operations and intuitive evalua-
tions. Micropatch enables a proposed model to be quickly
programmed, evaluated, easily modified, set aside and
Simulation Aided Design . . . Stored programs may be re-
called to assist component selections, search for para-
meters, conduct design concept validations and perform
evaluations of a design’s operation in untested applications.
Simulation for Test and Checkout . . . Micropatch simula-
tions are i i for i parts,
products or and operating 5
Simulation for Operator Training . With methods similar
to those used for teaching, electronic program storage con-
verts a Micropatch analog/hybrid computing system into a
general purpose operator training simulator.
periodically recalled.
ELECTRONIC PATCHING
To simulate a model of differential equations, micropatch applies both electronic switching and patch cord
programming. Electronic switching programs a model's basic framework. Patch cord programming adds non-
linearities and other subleties that are common to analog computer simulations.
Electronic switching is implemented through a set of micropatch attenuator-switch networks, each of
which is coded with an eight bit programming word. The host digital computer formats a set of equations
into a list of programming words. When individual networks are coded, a program is electronically
patched,
At the digital computer, progr i is initi: from differenti: ions that are exp! ina
state variable form. To use the microp: progr i , State variable equations are reduced
to combinations of three principle ingredients . . . variables, first derivatives (with respect to time) of
variables and attenuators. Equations are of the general form:
X (n) or dX (n)/dt = E A(k1)*X (m1) +A (k2)*X (m2)... + A (kiX (mi)
A()*X() is aright hand side term, and
m1, m2, . . mi are variable selectors,
k1, k2,. . ki are attenuator selectors.
where:
nis a left hand side variable selector.
For each equation, programmers assign a left hand varia-
ble selector. For each right hand side term, p
designate the term’s polarity and assign attenuator and
variable selectors.
Software variable selectors are hardware summer-integra-
lor ifi i n i! it of the variable se-
lector also assigns the amplifier that is to simulate the
variable.
assign the pi
terms are ly any function that can be
switch networks that operate with the
Micropatch attenuators are programmed much like simple,
coefficient potentiometers but they are considerably more
complex. They simulate complete equation right hand side
terms. Essentially, the terms are created as transfer func-
tions of right hand side variables. An attenuator transfer
function may be as simple as a variable multiplied by a
constant or as complex as a multi-amplifier, non-linear
function of a variable.
Preliminary set-up operations establish the transfer func-
tions that are performed by each attenuator network. Soft-
ware attenuator selectors call specific transfer
with analog computer operational elements.
An attenuator network inherently provides sign determina-
tion and the multiplication of a variable by a digitally set
constant. Programmers may optionally add variable multi-
lic nN, division, diode function generation, diode simu-
lated discontinuites, complete patch panel programs and
even external devices and sauiprnent. The linreatricted
choice of giv lhe versa-
tility to simulate any model that is within | Serra, analog
computing capabilities.
Electronic patching is handled entirely by individual at-
Variable and attenuator transfer
to be appropriate right hand side terms.
as shown in the
are
S
itch Network
itch network
SELECTED VARIABLE T OPTIONAL 1
FUNCTION OF SELECTED VARIABLE
4 EXTERNAL + +
LPROGRAM |
dig
ital computer data word bus
AMPLIFIER
INPUTS
GAIN 1
JAIN 10;
T
BS
B4 B3
B2 B1
Bo
MICROPATCH PROGRAMMING WORD
GENERAL CAPABILITIES
A fully ded micropatch cc
unit handles up to eighth order linear or non-linear simulations. Pro-
gramming is performed electronically based on a patched set-up of computing elements that are shown in the
photograph and described below.
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aa MICROPATCH
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si s
sim-
ulate equation variables. Each ssi requires the use
of one amplifier. The amplifier’s role as a summer or an
integrator determines whether the equation is algebraic or
differential.
Integrators have three mode electronic switch networks
that are independently controlled with patch panel logic.
Operation may be slow or high speed as determined by
time scale logic. Initial conditions are entered by adjust-
ing the manual potentiometers that are located to the
right of the patching area.
pe ilar ie ‘Switch | Network . As shown on the Micro-
itch A itch Network the outputs
ond esis of sixteen networks are terminated at the patch
panel. To simulate linear terms, where a variable is multi-
plied by a digitally set constant, the output is simply
patched to the input terminal. To simulate more complex
terms, the output is patched to an external program of
operational elements, The input is patched from the exter-
nal program.
Manual
provide manually ica attenuation of ‘variables, Equa-
tion terms may include knob adjustments by patching
a manual as the external
function.
Dividers . . . Two networks may be
i dividers, or square root
extractors | ot input variables, Two attenuator-switch net-
poedee to electronically program a multiplier
ider. One output is patched to the “X” terminal; the
other i is abides to the “Y” terminal.
Other Functions . . . Inputs to and outputs from remote pro-
grams may be transported to the patch panel via eight
trunk lines. Patch panel trunks are convenient terminations
for attenuator transfer function inputs and outputs. One
termination “‘f (t)”is reserved for time dependent forcing
functions such as sine, saw tooth or square waves, digital
computer generated functions or any input of the user's
choosing.
GP-10 ANALOG COMPUTING UNIT
The GP-10 is a traditional, patch cord programmed analog computing unit. It has a capacity to
simulate up to fourth order linear or non-linear models. For larger requirements, a number of
GP-10 or other computing units of the 7000 series may be combined into single operating
systems.
si A
1 thru 4 may be used
as summers, integrators, high gain operational amplifiers
or as logic controlled, single pole, double throw electronic
switches. Each has: a precision summing resistor network
with patch panel gain 1 and 10 values; provisions for up
to four integrating capacitors; a three mode electronic
switch that is independently controlled with patch panel
logic; an attenuator for entering initial conditions.
Eight are located to the right
of the patching area, Each is a grounded potentiometer
that has its top end and wiper terminated at the patch
panel. Coefficients are set with an external digital volt-
meter. Depression of the push button that is associated
with each attenuator places an input/output voltage ratio
on a potentiometer readout bus. While the button is de-
pressed, the attenuator is adjusted until the desired setting
is observed.
Logic applied to the SW switch control termination creates
two summing junctions, Either the SJ or SJ’
junctions is active depending on the switch control state.
An ampltiers ie Programmed as an snlesrator by patching
and app witch control
eget The Le ne aes a halos of two Yooibask capacitor
values. In slow time operation capacitors B and .1B and a
gain 1 input resistor produce 1:1 and 10:1 time scales; in
high speed operation an internal relay switches the time
scales to 400:1 and 4000:1. The OP termination is the sys-
tem’s mode control bus. For centralized integrator mode
operation, the SW switch control is patched to the OP
bus, Integrator initial conditions may be entered by an
attenuator that is located to the right of the patching area
or applied with a patched input to the IC termination.
An amplifier is programmed as a summer by patching a
resistor as the feedback. When there is no switch control
patching, SJ is the active summing junction. In this condi-
tion, SJ and SJ’ may be Hera line together so that the initial
network p resistor and the
IC termination is one wien summing input.
An amplifier is programmed as an electronic function
switch by patching the appropriate feedback element and
switch control logic.
Summers ... Amplifiers 5 thru 8 may be used as summers,
inverters or for special functions that require high gain
operational amplifiers. Each has a precision resistor net-
work. Amplifiers 5 and 6 have patch panel gain 1 and gain
10 values; amplifiers 7 and 8 have gain 1 values. Ampli-
fiers 7 and 8 also have provisions for function generator
networks,
An amplifier is programmed as a summer or inverter by
patching a resistor as the feedback.
ider . Two ‘iplier networks may be
used as multipliers, dividers, squarers or square root ex-
tractors. Each network produces a current that is propor-
tional to the X and Y input voltages. When the network is
patched as an input to an operational amplifier that has a
resistor as the feedback, the amplifier’s output is the prod-
uct of the input variables. When the network is patched as
the amplifier's feedback, the amplifier output is the quo-
tient of the two input variables.
Function Generators . . . Function generator networks mex
be used as an 's input or
create either arithmetic or empirical functions of facut
variables. Possible arithmetic networks include logarithm,
squaring, cubing, sine and cosine generators. Variable
diode function generators may be used for adjustable,
straight line approximation of empirical curves.
Trunks .. . Eight uncommitted trunk terminations are avail-
able for transporting variables to and from the patch panel.
The trunk terminations help organize patch panel inter-
connections with external devices and other computing
units.
Reference . . . Reference is used as computer unity for
entering constants and for scaling output variables. A
precision positive and negative 10 volt reference is avail-
able as patch panel terminations.
Accessories . . . An assortment of accessories, in the form
of networks and devices, are offered to simplify program-
ming and provide more realistic simulations. The pail
sories discor
vide controller functions, simulate, ese processes Gnd
g! y expand the
REPLACEMENT OF MANUAL WITH DIGITAL ATTENUATORS
Multiplying digital/analog converters, set from a host digital computer, may either replace or be added in
series with the manual coefficient potentiometers. The MDAC’s attenuate analog variables by digital data words.
Setting occurs from digital computer data that is transferred via the central interface and bus system.
CONTROL UNIT
Simulations are controlled
and monitored with the 7986
Control Unit. A keyboard
type panel and LED displays
provide a desktop base of
operations for all system
analog computing units.
Mode Control... Logic control of analog computing
unit and central time base integrators is produced
from operation of the MODE CONTROL push buttons
and LED state indicators. The four modes are des-
ones as follows:
. The initial condition mode is a manual reset of
Si time operation integrators.
HD... Hold mode logic electronically di: the
Compute Time Period . . . As indicated by the COM-
PUTE TIME display and measured in computer time
units, the compute time period is the full scale X axis
coordinate of XY oscilloscope and recorder time res-
ponse curves. The X axis is generated by an internal
time base integrator that sweeps from negative to
positive reference where the duration of the sweep
is the compute time period.
summing resistor networks from integrator inputs. In-
tegrators hold their values until released-either into the
initial condition or operate modes.
fe) The operate mode is a manually actuated run
state for slow time operation integrators.
RO. Repetitive operation is a high speed run state
where integrator time constants are reduced by a factor
of four hundred and modes are alternately switched
from initial condition to operate. Integrators are held in
the operate state for the duration of the compute time
period. When observed on an oscilloscope, repetitive
operation outputs appear as solid XY curves.
Cc time period have a range of 10 to
90 time units with increments of 10. To change a set-
ting, first the “CTP” button is depressed and then the
period’s ten’s digit is entered.
A toggle switch located to the left of the COMPUTE
TIME display enables the oscilloscope or recorder’s
horizontal input to be either the time base or X Read-
out Bus. In the TIME position, Y vs. time response
curves are produced; in the AMP position, Y vs. X
curves occur.
Other Data Entries . .. The keyboard can also be used
for communication with external digital devices.
Facilities oe available for parallel, hexidecimal data
through the 7976 Interface Network.
Keyboard Functions . . . Amplifier address
and other numeric data inputs are entered via push
The “INT, “A” and ‘“‘B” buttons are for external use
and have no significance for general
buttons that are arranged in a sixteen key-
board matrix.
Monitor of System Variables . . . A two axis electronic
address places the outputs of any two analog comput-
ing unit amplifiers on the X and Y Readout Buses. An
operator may choose to either simultaneously plot the
X and Y selections as a function of time or Y as a func-
tion of X.
Y Address ... An amplifier output is placed on the Y
Readout Bus by first depressing the “Y” push button
and then entering, in sequence, a two digit number
that selects the computing unit and amplifier loca-
tions. The selected Y amplifier location apears as the
Y ADDRESS numeric LED display.
X Address .. . Depression of the “X” push button
followed by the computing unit and amplifier loca-
tions places a selected amplifier output on the X
Readout Bus. The selected X amplifier location ap-
pears at the X ADDRESS display.
7000 Analog/Hybrid Compu-
ters are normally housed in
an electronic enclosure. A
desk top chassis is also of-
fered for operation of single
analog computing units.
7000 operations.
Digital Voltmeter . . . Coefficient attenuator settings
and measurements of amplifier outputs are perform-
ed by a digital voltmeter that features a 3% place
accuracy and autopolarity. Readings appear at the
DIGITAL VOLTMETER display. To the right of the dis-
play is a toggle switch that connects the digital volt-
meter input to either the system’s potentiometer bus
or the X Readout Bus.
Overload . . . The OVLD display is a state indicator
of the system’ s overload bus. The bus is enabled by
individual analog computing unit networks as an
alarm to indicate when any of the system’s amplifier
outputs exceed an overrange amplitude. If the toggle
switch to the display’s right is in the W/HD position,
an overrange amplitude will place the system into the
Hold Mode. The hold feature allows an operator to
determine the overranged amplifier location and the
time at which the overrange occurred.
OPERATION WITH AN EXTERNAL DIGITAL COMPUTER
A 7000 system is made into a hybrid computer by con-
necting an external digital computer to an interface
1/O port. Three parallel, eight bit words, arranged in
configurations that are compatible with integrated
circuit peripheral devices, enable the digital compu-
ter to control 7000 operations and to handle digitized
analog variables. Some standard hybrid computing
functions are described below.
Monitor of System Variables .. . An operator, may
transfer address of the X Readout Bus from the Con-
trol Unit to the external digital computer. The X Ad-
dress network thereby becomes an analog multi-
plexer for digital conversion of analog variables.
Analog/Digital Conversion . .. In addition to the multi-
plexer function, interface features allow the digital
computer to start the analog/digital converter, sense
the end of conversion and place digitized analog vari-
ables on a bi-directional data bus to be read by the
digital computer.
Digital/Analog Conversion . . . Digital/analog con-
version is applied to analog simulations by atten
tion or voltage representation. The multiplying di:
tal/analog converters that are located within indivi-
dual analog computing units attenuate analog varia-
bles by digital data words. An extensive network of
ANALOG TO DIGITAL CONVERSION
The conversion of analog variables to di
conditi to meet specific use
ital data is
r requi' An
internal printed circuit connector provides a facility
MDAC’s and the 7000 bus structure enables analog
simulation constants to be quickly set from the host
digital computer.
In addition to the local MDAC’s, a central digital/ana-
log converter is available to produce voltage func-
tions that are generated by the digital computer. The
DAC’s output appears at the analog computing unit
panel as a special function generator.
Time Interface .. . An analog compute time clock is
ilable for sy’ ion of digital pro-
grams with analog computer simulations. The clock
pulses are discrete analog time units. By sensing the
clock pulse train, analog/digital or digital/analog
co! ion can be i with the simulation’s
time domain.
Operator Interaction . . . While it is anticipated that
the digital computer will be operated primarily from
its own data entry facilities, there are provisions to
input parallel, hexidecimal data from the Control Unit
keyboard. Control Unit entries may be used for nu-
meric data inputs or as codes to actuate digital com-
puter routines.
There are also provisions for the digital computer to
sense integrator mode control logic and to issue bit
state commands.
When synchronized with the analog compute time
clock, conversions may be time as well as space
oriented. Complete time dependent functions are
igitized by bling the converter’s start logic with
for general analog/digital converter op: with-
out a committment to a particular design. The type of
converter (its linearity, resolution, speed, etc.) can be
the clock pulse train. Digitized functions are entered
as strings of data words where each data word re-
determined by user needs and future adi
in converter technology.
Conversions may be handled entirely by the internal
7000 system ADC, be shared by the internal and an
external ADC or be handled entirely by a converter
that is dedicated to the host digital processor. Stand-
ard converter assemblies are offered but custom
units are practical if standard designs are not suit-
able. The modification of an existing design or imple-
mentation of a new one may add only a minor ex-
pense to the total system cost.
Internal and external ADC’s may both utilize the X
Address network as a system multiplexer. Digital
computer address commands to individual analog
rep a variable’s amplitude at a specific point
in time.
Strings of data words can also be returned to the
analog simulator as time response functions. By
synchronizing the digital/analog converter with the
analog compute time clock, analog/digital and digi-
tal/analog conversions can occur simultaneously or
independently at the same time position. Complete
curves may be converted, processed and then return-
ed as time dependent functions.
Conversion of complete functions and the general
employment of the analog compute time clock are
computing unit ip place
outputs on the X Readout Bus. The X Readout Bus is
the normal input to the internal ADC and is also avail-
able for external use.
COMDYNA, Inc.
1g 7000 . With an ible time
unit reference and simple software instructions, digi-
tal computer programs and analog computer simu-
lations may be space and time coordinated.
COMPUTERS FOR DYNAMIC ANALYSIS
305 Devonshire Road, Barrington, Illinois 60010, (312) 381-7560