EAI Report No. 017 — April/May 1970

This is an English translation of the original German-language periodical “EAI — Report, Mitteilungsblatt der EAI Electronic Associates GmbH, Nr. 017, April–Mai 1970.”

Cover Page

EAI — Report Newsletter of EAI Electronic Associates GmbH 51 Aachen – Bergdriesch 37 April – May 1970 No. 017

The cover shows the EAI 430 DATAPLOTTER, which provides automatic conversion of computer-generated data, either on-line or off-line, into graphic form — quickly, accurately, reliably, and efficiently.

EAI Deutschland — Sales Staff Map

A map of West Germany showing regional sales coverage. The sales engineers serving the various regions are:

Dipl.-Ing. D. Meerkamp
Dipl.-Ing. H. Leuschner
Dipl.-Ing. W. Ahn
Ing. V. Koch
Dipl.-Ing. K. Wenkemann

Letter from Management

Bad Aachen, May 1970

Dear Report Reader,

It is a pleasure to present EAI Report No. 17 — fresh from the press.

After a very successful fiscal year 1969 — in which sales grew by 40% compared to 1968 — EAI GmbH is preparing for a great 1970. In September of this year, EAI-USA will celebrate its 25th anniversary and is therefore one of the oldest and most experienced, yet completely independent, manufacturers of analog/hybrid computers and complete hybrid computing systems.

This Report highlights, among other things, the newly conceived EAI-640 Digital Computer, the DATAPLOTTER EAI-430, and the hybrid-interface capability for the TR-48 analog computer; it also covers the newly introduced EAI-590 and EAI-680/690 hybrid installations.

Additionally, a report is presented on the recent publication by Dipl.-Ing. Fritz Vogt (Aachen) on “Amplitude and Phase Measurements with the Electronic Analog Computer.”

The comprehensive European training and instruction program is also highlighted, along with this year’s participation in the Hannover Trade Fair.

A qualified, experienced consulting staff is at the reader’s disposal for discussions of technical problems.

Under the leadership of Ing. grad. D. Schwarz, the customer service department has been expanded in the southern region. In the southern area, the service center of Mr. E. Roth has since 1 July 1969 handled customer service for EAI systems and Brush devices in cooperation with the Aachen EAI customer center. Mr. Roth’s office is centrally located in Munich, 8 München 2, Dachauer Str. 42. Tel.: 0811/591271.

Applications engineers are available for problem discussions or system analyses, and registration is welcomed for the many courses and EAI events planned for 1970.

EAI thanks all business partners for the trust and interest shown, and will continue to strive to meet all expectations.

With kind regards, EAI ELECTRONIC ASSOCIATES GMBH (Henk W.A. Junghauer) Managing Director

New — Digital Computer EAI 640

New Configurations of the EAI-640 Digital Computer

EAI offers three basic configurations for the EAI-640 Digital Computer immediately: 640/100, 640/200, and 640/300. Each of these combinations is fully operational in itself and can be expanded as needed by adding further peripheral devices.

EAI-640/100

The EAI-640/100 is a basic system that provides the user with limited speed and performance without, however, restricting the machine’s possibilities. Standard equipment includes the memory protection system and fail-safe backup (overflow protection). In addition to the standard I/O data channel, the EAI-640 also includes — besides the standard I/O data channel — an additional channel for direct memory access (transfer rate 93 kHz in Single Word Mode, 600 kHz for both modes via a so-called “Cycle Stealing” basis). Memory expansions and additional peripherals can be added as needed.

Equally, the software capabilities of the EAI-640/100 are not limited to those of the hardware. The 640/100 software includes the Symbolic Assembler, FORTRAN IV, Digital Operations Interpreter, Text Editor, Debug, and mathematical and user routines. All 640/100 software is designed to work in an 8K Single Word Mode environment; complete upward compatibility with the other 640 systems is ensured.

EAI-640/200

The EAI-640/200 is a mass-storage system with 8,192 16-bit words of core memory and high-speed cassette tape I/O. It is suitable for both measurement and data processing and testing. The EAI-640/200 hardware connects 8,192 core memory words and the high-speed cassette unit (300 cps/sec read, 150 cps/sec write). The Teletype Model 35 in 640/200 is also available as a high-performance operator device. Standard equipment includes a high-precision multiply unit, an interrupt system with multiple levels, memory protection, as well as the standard I/O data channel with a direct memory access channel. The cassette tape unit is a highly compact unit; each of the four bands can be read and written independently. A complete band holds up to 200,000 words; insertion of a band takes a simple single motion. The built-in software is the same as 640/100, plus Cassette Tape Library software (Cassette Tape Library) provides a record storage and retrieval system. Data lengths are variable, corresponding to the data organization requirements.

EAI-640/300

The EAI-640/300 is designed so that the requirements for handling complex real-time problems — from program development to testing — are fully met.

The 640/300 contains 32,768 16-bit core memory words, with the Gleitkomma-Processor (floating-point processor) as an important part of the 640/300 software. Fast 32-bit floating-point operations lead to higher computing speed and simplicity of programming.

The Gleitkomma processor speeds up FORTRAN object programs, making it possible to substitute floating-point operations for many time-critical iterations or machine-language operations. This enables the user to save time in both programming and error correction. This means that less time is spent on programming details and more on problem handling itself.

The 640/300 operator console in desktop design includes a 35-line ASR Teletype unit with a permanently connected keyboard for all operations. Also available are: high-speed multiply unit, division, square root, standard I/O data channel, and a channel for direct memory access as standard equipment.

The software includes the Symbolic Assembler, FORTRAN IV, Digital Operations Interpreter, Text Editor, Debug, and mathematical and user routines.

New Peripheral Devices for the EAI-640 Digital Computer

Cassette Tape Unit EAI-640/700

The cassette tape unit 640/700 is the economical answer to problems of program and data storage and retrieval. It serves for program loading, data input, data exchange storage, data backup, and program backup.

The cassette tape unit contains four separate tape magazines. The tape magazines are housed in exchangeable bays, each of which can hold two independent magazines. Loading the cassette unit is done by means of the tape magazines.

The storage capacity of each band is 50,000 16-bit words, resulting in a total storage capacity of 200,000 words per cassette unit. Bays with 50 or 100 ft tapes are also available.

The four bands can be used independently and in any sequence; data can be written and read on a band in “records” format — here the “record” length is variable, corresponding to the data organization requirements.

The input/output to tape occurs continuously at a speed of 10 inch/sec with a density of 600 bit/inch, resulting in a transfer rate of 333 words/sec.

Magnetic Tape Unit EAI-640/710

The EAI-640/710 includes a magnetic tape unit and a magnetic tape controller. The controller can connect up to three tape units in addition to the 640/711 units. The 9-track tape units are IBM-compatible. The tape units operate at 12.5 inch/sec with a write speed of 800 bit/inch, i.e., the transfer rate is 10 kHz.

The maximum tape reel size is 7 inches, resulting in a tape length of 600 ft.

The magnetic tape units can read forward and backward. Writing is only possible in the forward direction.

Line Printer EAI-640/600

The EAI-640/600 line printer prints at a maximum 80 columns at a speed of 356 lines/min for 80 columns. The print speed increases to 1110 lines/min with a corresponding reduction in column count:

356 lines/min at 80 columns
460 lines/min at 60 columns
650 lines/min at 40 columns
1110 lines/min at 20 columns

The printer is a drum model with 64 possible alphanumeric characters in each line. It prints 6 lines per inch.

Card Reader EAI-640/500

The economical EAI-640/500 card reader reads standard cards with 12 rows and 80 columns at a speed of 200 cards/min. The cards are read photo-electrically column by column. Cards can be inserted or removed during the reader’s operation, so that these operations cause no time delays. The input device has a capacity of 400 cards, as does the output device.

A comprehensive EAI-640 handbook in German is available on request.

Please contact us for information: (0241/26042).

(Volker Koch)

HYBRIDIZE YOUR COMPUTING LAB WITH AN EAI-640 DIGITAL COMPUTER!

Major EAI News for TR-48 Analog Computer Owners (approx. 150 in West Germany)

Since about half a year ago, EAI has been offering a hybrid expansion for the TR-48 analog computer.

It makes from the TR-48 a universally deployable hybrid computer, placing the computing power of modern EAI-590 and EAI-690 hybrid systems at the user’s disposal.

The following new aspects arise from “hybridization”:

The economic application range and efficiency of the TR-48 is expanded.
A hybrid standard coupling network is available — the EAI-693 Interface — which has been used in over 40 cases.
A particularly flexible digital computer, the EAI-640, is available, which is already in use at over 60 computing centers.
A comprehensive hybrid standard hardware and software package is available.

The hybrid TR-48 expansion includes:

HARDWARE:

Operating speed control of the integrator
Operating speed control of the track/store units
Universal “sample lines” for event recognition
Universal “control lines” for event generation
D/A multipliers (2 different generosities are available)
They can be used as standard D/A data converters or as coefficient potentiometers
A/D data channels (2 different signal ranges)
Hybrid core memory access capability
Coupling network oscillator

SOFTWARE:

Function storage and replay
Time delay
HOI = Hybrid Operations Interpreter
Over 30 hybrid user programs
Hybrid oscillator
Hybrid error-search program
- All standard software programs

Advantages:

In the future, the TR-48 analog computer can be operated in parallel with the most modern modular hybrid computers, without having to procure another expensive and space-wasting device from any other manufacturer.
The reader is already acquainted with EAI’s other advantages — such as the extensive EAI training program and the qualified EAI service.

The advantages of EAI systems are best discussed in detail by a sales or applications engineer. Please contact them for more details.

(Dipl.-Ing. K. Schwarz)

EAI SYSTEM SUPPORT

EAI is the only analog/hybrid computer manufacturer offering complete system service to meet user needs: equipment maintenance, personnel training, and the application of the computing systems. This extensive service has been largely responsible for the high degree of customer acceptance and regard for EAI and its scientific computing systems.

Software: Hybrid hardware requires adequate software to be a complete system. EAI provides a complete and comprehensive software package which includes the hybrid programming system, applications reference library techniques and case history library as well as iterations and maintenance manuals. EAI software support is continuing, updating programs and techniques to keep pace with equipment change, hardware modifications and special applications.

Maintenance: EAI excels in custom-designed service programs — from minor equipment adjustment to long-term maintenance contracts. Service Division refurbishes and updates any computing equipment. EAI personnel will assume full responsibility for maintaining customer equipment or supplement the customer’s own maintenance staff.

Education and Training: EAI Computation Centers also provide facilities and instructors for EAI’s program of regularly scheduled training courses. Students receive instruction in courses ranging from basic analog computer techniques through equipment operation and maintenance to advanced analog and hybrid programming. Special courses cover topics such as computer applications in the process industries and biomedical engineering.

Commissioning of the Hybrid Analog Computer EAI-680 at the Technische Hochschule Wien

On 4 December 1969, the hybrid analog computer EAI-680 was commissioned at the Institute of Mathematics of the TU Wien.

At a working meeting, Prof. Dr. R. Wurzer welcomed the numerous guests, including representatives of the Federal Ministry of Education, Senate members of the TU Wien, representatives of the Federal Chamber, the Austrian Society for Cybernetics, and the press.

The rector pointed out in his address that the Technical University, through the acquisition of this computing system, would in future be able to meet the growing demands of research and teaching.

Following the welcome, Prof. Dr. E. Bukovics, Ordinary at the Institute for Mathematics, described the computing system, giving a brief overview of the history of predecessor systems and then an outlook on the near future. Prof. Bukovics thanked EAI for the generous support received in procuring the necessary funds.

The reception closed with a demonstration of satellite simulation performance of the installation under test conditions.

In the afternoon, Dipl.-Ing. C. Willems from the EAI European Hybrid Computing Center in Brussels visited the application areas of hybrid computing systems.

The hybrid analog computer EAI-680 currently has a capacity of 70 amplifiers and 30 integrators. The computer can be expanded to over 200 amplifiers in due course.

It is planned to expand the computer in the course of the current year with the addition of a digital computer EAI-640 (16 bit, 1.65 MHz, 8-32 k) and the hybrid coupling network EAI-693 into a full hybrid EAI-690 system.

The installation provides Austrian science with a novel tool for partial differential equations, simulation of heat transfer and diffusion processes, optimization problems, and study of stability limits of differential equations.

(Dipl.-Ing. D. Meerkamp)

Commissioning of a Hybrid Computing System EAI-590 at the Deutsche Forschungs- und Versuchsanstalt für Luft- und Raumfahrt e.V. in Braunschweig

On 27 November 1969, the hybrid computing system EAI-590 was handed over at the computing center of the Deutsche Forschungs- und Versuchsanstalt für Luft- und Raumfahrt (DFVLR) in Braunschweig at a small commissioning ceremony.

The system consists of the analog/hybrid computer EAI-590, the hybrid interface system EAI-693, and a digital computer EAI-640. The digital computer currently has approximately 70 amplifiers in the analog section. It is equipped with a Teletype and high-speed tape unit and provides the analog section with a full complement of I/O devices. The connection of the EAI-590 with the already existing analog computer — EAI-580 — is planned, as is an expansion of the interface system and the digital computer.

In the absence of the DFVLR director, Prof. Dr. H. Blenk, who welcomed the numerous guests from research and industry, Dipl.-Ing. C. Willems (European Hybrid Computing Center of EAI in Brussels) gave an overview of this relatively young but future-oriented branch of technology for scientists and engineers.

After this lecture, a theory-illustrated application of hybrid computing systems was discussed, followed by a personal conversation with DFVLR staff and EAI personnel to discuss details of the system.

(Dipl.-Ing. D. Meerkamp)

Amplitude and Phase Measurement with the Electronic Analog Computer

By Dipl.-Ing. F. Vogt, Scientific Associate of Professor Dr.-techn. Th. Wasserrab, Institute for Communications Technology and Electrical Drives, Technische Hochschule Aachen.

1. Problem Statement

From a heavily distorted current, the magnitude of the 50 Hz component and its phase angle relative to the sinusoidal mains voltage are to be determined and displayed in a Lissajous figure.

Measuring devices that can measure phase angles require sinusoidal input signals — devices that determine and filter the phase angle. A reference source must therefore be used whose phase error can be compensated by using two identical devices.

Since a direct measurement with the available devices was not sufficient, the measurement was carried out with the aid of a filter on the analog computer.

2. Construction of the Band-Pass Filter

In order not to distort the phase angle between current and voltage, both signals must pass through a filter with equal amplitude and phase response. For multi-element filters, this equality can only be achieved with considerable effort; on the analog computer, however, even for 50 Hz two equal filters with high quality can be realized. If one takes as a filter model the parallel resonant circuit of Figure 1, the following equations can be established:

u = L · di_L/dt; i_L = (1/L) · ∫u dt
i_C = C · du/dt
u = e − R_v · i
i = i_L + i_C + i_R; i_R = u/R

This gives the differential equation:

(u − e)/R_v + (1/L) · ∫u dt + (1/RC) + du/dt = 0

which, after division, can be brought to the following form:

du/dt = (1/R_v·C) · (e − u) − (1/LC) · ∫u dt − (1/RC) · u

This differential equation is solved on the analog computer using the circuit shown in Figure 2.

With potentiometer P1, the factor 1/LC and thus the resonant frequency is set; with potentiometer P2, the factor (1/RC + 1/R_v·C) is set, which influences the quality and bandwidth.

Both filters were set to a resonant frequency of 50.0 Hz and a quality of 100, ensuring equal amplitude and phase for the two filters.

3. Measurement of Current by Magnitude and Phase

Since a measurement would require an analog computer to be used anyway — also to determine the measurement data — the analog computer was also used here. For the desired magnitude measurement, the analog computer should be used; it should depend only on the momentary value of the mains voltage and frequency and not on the parameters of the circuit (d.h., it should be proportional to the momentary amplitude of the mains voltage regardless of the instant of time and the mains frequency). For this reason, the analog signals are first converted into rectangular functions u_r and i_r, which are then divided smoothly and gently using rectification and smoothing to make the ratio |i|/|u| available without the need to carry out a division of two time-varying quantities.

4. Measurement of Active and Reactive Power

With the quantity φ already determined, the quantities k·sin φ and k·cos φ can be obtained by the following calculation. Both rectangular signals pass through a 100 Hz switching circuit, so that one obtains the filtered amplitude and the other the filtered phase. The point of intersection of these two signals is: u = G·sin(ωt) and i = k·G·sin(ωt − φ).

Multiplying the current by this auxiliary voltage, one obtains:

i · u_h = (1/2) · G² · (cos φ − cos(2ωt + φ))

This corresponds to a DC component (1/2)·G²·cos φ and an AC component, which can be separated by a capacitor or smoothing element. By multiplying with 100 Hz one obtains two peak rectifications in series, resulting in two values: k and k·cos φ.

The remaining dependence on G²/2 is eliminated by dividing by the AC equation:

u · u_h = (1/2) · G² · cos(2ωt)

after which one has: k·sin φ = √(k² − k²·cos²φ), from which k·sin φ can be computed for any ordinate k·sin φ belonging to the abscissa k·cos φ.

This procedure is not only elegant but also requires a considerably larger number of nonlinear components, which needs attention because the error for cos φ in the range of small φ is greatly amplified. This difficulty can be avoided, however, if one computes sin φ differently by inverting the auxiliary voltage u_h = G·sin(ωt + 90°), thereby obtaining the corresponding expression.

5. Extending the Measurement Range

In order to work accurately and without disturbance on the analog computer, it is necessary that the input quantities lie within a range between one-third and the full reference voltage, and that the full computing voltage applies. Additionally, the current without galvanic coupling had an input impedance that was too large. Through current-dependent scaling of the transducer, it was possible to make the analog computer’s input size as small as desired. In this way the assigned task could be resolved with the required accuracy.

Summary: The above method makes it possible to determine, without iterative procedures, the vector envelope of a non-sinusoidal current. The analog circuits described allow direct representation in polar coordinates and in Cartesian coordinates.

European Training and Instruction Program

EAI Training and Programming Courses — Calendar 1970

Course	Date	Location	Language	Cost (DM)
Analog: Introduction and Simulation	4–6 Nov; 25 May 1970	Burgess Hill	English	800
Analog: Simulation and Techniques	6–11 Apr, 6–10 Jul, 5–9 Oct	Brussels	French	650
Analog: Simulation and Techniques	20–24 Apr, 15–19 Jun, 14–18 Sep	Aachen	German	650
Analog/Hybrid-Rechner	25–29 May	Brussels	French	650
Hybrid-Rechner	22–26 Jun, 28 Sep–2 Oct	Aachen	German	650
EAI/490 Programmierung	17–21 Feb; 20–24 Apr; 19–23 Oct	Brussels	French	635
EAI/490 Programmierung	various dates	Aachen	German	635
Hybrid Computing	various dates	Burgess Hill	English	800
EAI 640 Programming	17–21 Feb; Jan 19–23	Brussels	French	535

[condensed — the full table lists approximately 20 course types with multiple session dates throughout 1970 in Brussels, Burgess Hill, and Aachen.]

The Fabulous New EAI 430/200 Data Plotter

Delivery of the high-speed digital plotter DATAPLOTTERS EAI 430/200 has begun. After the system 430/100 with a drawing area of 78 × 91 cm (31 × 36”) had been in use in various branches of industry for several months, the 430/200 now provides the user with a drawing surface of 137 × 193 cm (54 × 76”), on which even extremely large paper sizes can be placed. A large American oil company uses the 430/200 for plotting geophysical data using a digital computer IBM 360.

The DATAPLOTTERS EAI 430/200 uses a unique “hybrid plotter” concept, combining the speed of the analog (30 cm/sec) with the accuracy of the digital (0.032 mm). This accuracy applies not only to straight lines but also to curve drawing. Input can be via magnetic tape as well as on-line with a digital computer.

EAI-690 Hybrid System — Presentation

At the European Hybrid Computing Center of EAI-ELECTRONIC ASSOCIATES INC., EUROPEAN DIVISION, 116–120 Rue des Palais, BRÜSSEL 3, Belgien:

In the past year, multiple seminars were held several times at the EAI European Hybrid Computing Center in Brussels on the working method and applications of hybrid computing systems. The strong interest encouraged EAI to hold another such seminar this year.

Dates: Thursday 18 June and Friday 19 June 1970; Monday 22 June and Tuesday 23 June 1970.

At this two-day seminar, both the hardware and the software of the EAI-690 hybrid system will be explained. In addition, a number of typical application examples will be presented in theory and practical demonstrations.

A letter of invitation with a detailed program will be sent shortly; registration is welcomed.

EAI-GmbH at the Hannover Trade Fair: 25 April – 3 May 1970 Hannover-Messe, Hall 12, Stand 110

Showing:

Hybrid system EAI-590
Analog/Hybrid computer EAI-380
DATAPLOTTER EAI-430
DART data acquisition and recording system

Upcoming (announced): 17 June – 24 June 1970, ACHEMA Frankfurt

PACE system (automatic monitoring and measurement data processing of analytical devices such as gas chromatographs, mass spectrometers, etc.)

Brush Mark 220 Recorder (Model 15-6327-50)

Light, simple to operate… yet tough and accurate

The two-channel high-speed recorder Mark 220 from Brush Instruments Ohio, USA, introduced in 1967, is here once again presented as one of the most compact, precise, and reliable recording devices on the market.

Two separate 40 mm analog channels, plus 2 event markers, precision seconds timer.
Servo-controlled pen motor with contactless (inductive) feedback achieves high accuracy (better than 99.5% of full scale), writes square waveforms (approximately 5 ms rise time) without overshoot.
Patented ink-free pen system: pens write on special Rechteckflachen with equally strong, straight, continuous strokes; immediately dry — no smearing; the only maintenance-free direct-writer! The fluid lasts one year or 500 km of trace.
Patented Brush-Accushart paper (ceramic-coated) absorbs writing paste immediately — at a price of under 0.20 DM per meter.
Frequency range: linear (±2%) up to 50 Hz; write width from 40 mm to over 100 Hz in 10 mm.
2 differential inputs per channel (10 MOhm impedance), high noise rejection.
Total measuring range of built-in preamplifiers: 50 mV (full-scale) up to 500 V; all ranges protected against overvoltage to 500 VDC.
Precision paper feed electrically switched over print tacker (no data loss); paper speeds: 1, 5, 25, 125 mm/sec.
Fully transistorized; weighs only 11 kg.

This universal recorder is immediately available from stock. Data sheets, trial demonstrations, and non-binding quotations are available on request. Tel.: 0241/26041.

Brush Mark 260 Recorder — 6-Channel Portable

Save thousands of dollars each year… from the information revealed by your Mark 260’s traces…

Starting in 1968, Brush Instruments brought the Mark 260 to market as a follow-on to the successful 2-channel Mark 220 and quickly captured a strong market position.

6 independent 40 mm analog channels (up to 2 event markers), seconds timer.
Identical contactless servo pen motor system as the Mark 220.
Ink-free pen system, reliable and maintenance-free; frequency range 50 Hz/40 mm, 100 Hz/10 mm.
Built-in preamplifiers: 50 mV to 500 V full-scale.
Paper advance: 1, 5, 25, 125 mm/min and mm/sec, electrically switchable.
Fully transistorized; a 6-channel high-speed recorder weighing only 29 kg!

Data sheets, trial demonstrations, and quotations are available. Tel.: 0241/26041.

(Dipl.-Ing. H. Leuschner)

Digitally Controlled Function Generator (DCFG)

The DCFG is a genuinely new hybrid component with which analog functions can be generated quickly and reliably on an analog computer. EAI offers this as an extremely powerful tool for the hybrid computer programmer.

Advantages:

New Concept — New Possibilities: All functions are generated from specific X-Y values (no modification of X values or card-based function settings as is conventional); self-testing software is provided as standard; EAI is naturally pleased to supply special programs.

High Speed: In a few μsec the 16 breakpoints are set by the digital computer. The manual setting of function generators takes approximately 15–20 minutes.

Versatility: The slope can be represented “infinitely” — processes such as “dry friction” can be simulated, which could not be represented with conventional diode generators. Arguments up to 1000 Hz can be processed — approximately 50 times faster than the digital computer.

Flexibility:

Slope up to 400 Volts/Volt.
The digital computer is only used to set the function; it is then available for other tasks.
The frequency behavior is independent of the number of set function points.

Accuracy:

Static error: ±0.05%.
Slope errors do not add.
Dynamic error (dead band) at 100 Hz is less than 0.5%.

Reliability:

Low noise.
Virtual null drift.

Installation: The DCFG was developed to operate with standard EAI analog/hybrid computing systems (100 V oder 10 V). The DCFGs are housed in separate enclosures with their own power supply. Inputs and outputs of the DCFG terminate at the analog patchboard.

Operation: Each of the 16 X-Y points is described by a 23-bit word. The resolution is 0.5% (X) and 0.02% (Y).

DCFG Software:

Seeks optimal breakpoints.
Sets breakpoints and function values automatically in a few μsec.
Provides diagnostic programs for automatic testing.

Benchmarks: A government agency provided EAI with a test function plot. The agency used this to evaluate the capability of the DCFG. Note that on some portions of the functions the slopes are virtually infinite. Of particular interest is the scope trace at 1 kilohertz. This demonstrates the high function fidelity at high repetition rates.

DART — Data Acquisition and Recording Terminal

A highly economical solution for data acquisition and recording.

EAI introduces a completely new system for data acquisition and recording: DART (Data Acquisition and Recording Terminal). It provides in compact form a comprehensive, flexible, and most economical data logger, which meets approximately 90% of the market requirements for flexible, simple, and economical systems — but DART delivers as much as any system at half the expense and lower cost.

The dimensions of DART are 48 × 45 × 62 cm, with only the recorder unit separately mounted.

Key features:

Analog inputs from thermocouples, strain gauges, potentiometers, etc. in the range 0–10 mV, 100 mV, 1 V, 10 V, or 100 V. 10 switch-selectable channels, expandable in groups to up to 100 channels with fully flexible input management (single stepping, group selection, or continuous); either automatic single-channel scan or continuous scanning, or manual or external control; DART’s input handling is extremely flexible.
The analog-to-digital converter has a resolution of 0.05% with a conversion speed of 200/sec. The 4-digit display shows the converted value with the units selected.
The downstream parallel/series converter takes the digitized data in the fastest form, as required by the output device. Additionally, special characters such as line feed, carriage return, line erase, etc. can be entered here.
A series of peripheral devices such as tape punches, printers, magnetic tape, or a computer can receive the digitized data. The system’s output speed depends on the output devices; at tape punch output a maximum output speed of 10 channels/sec can be achieved.

Several additional features, which will also be housed in DART enclosures, extend the possibilities of the system.

The DART digital unit automates the query and digitization process by allowing a specific cycle to be specified, after which each time the front panel selector switch specifies the individual channel order. For monitoring purposes, upper and lower alarm values can be set that trigger an alarm output when exceeded or undershot. Particularly for querying thermocouple inputs, the linearization function is used, making a non-linear input linear within 0.1%.

The DART system is simple to operate, making the design effort for large-quantity production feasible, and the adjustment and alignment instructions are brief and clear. DART is therefore the ideal data acquisition and recording device for both industry, universities, and research.

(Ing. Volker Koch)

EAI 640 Digital Computer — System Summary (Back Cover)

(Der EAI 640 ist kein “und dann brauchen Sie noch–, und dann brauchen Sie noch”-Computer) (The EAI 640 is not a “and then you need this… and then you need this too” computer.)

Monolithic integrated circuitry
64 fixed-wired instructions such as: addition, subtraction, multiply/divide, square root, logic, register exchange, conditions
Fixed word length of 16 bit for data or instructions
8 and 16 k memory — plus memory protection option
Core memory: 1.65 μsec cycle time; basic system 8,192 words; expandable to 32,769 words
Indirect addressing with index register: unlimited number of memory words usable as index words
7 internal and 64 external interrupts (including interrupts)
I/O standard data channel, Single Word Mode/Record Mode, channel for direct memory access (DMAC)
A interval timer connection options
Software: FORTRAN IV, Real-Time Monitor, Symbolic Assembler, Digital Operations Interpreter, Basic Operating System, Debug and Update

The EAI 640 has so far been used a hundredfold as the most trusted digital computer — and paired with analog computers — in hybrid systems for science and research.

Electronic Associates GmbH 51 Aachen — Bergdriesch 37

Detailed information on the standard system EAI 640/100, 640/200, and 640/300 is available in the comprehensive German-language handbook, which will be sent on request free of charge.