English translation
EAI Report — September 1967, No. 012: EAI 580 Analog/Hybrid Computer System Introduction
This document is an English translation of the original German-language EAI Report, dated May–September 1967, No. 012, published by EAI Electronic Associates GmbH, Aachen.
EAI 580 — Introduction of the EAI 580 Analog/Hybrid Computer
In August 1967 the new EAI 580 Analog/Hybrid Computer was presented publicly for the first time. It is the thirteenth development by EAI Electronic Associates Inc. in the field of analog computing systems. On this occasion it is appropriate to provide a historical overview of EAI systems delivered during the 19-year history of Electronic Associates Inc.
Historical Overview of EAI Systems
1948 — Development of analog computing components for the U.S. Navy, which used them to build special analog computing systems.
1952 — Introduction of the EAI 16-24 D analog computer; a large, high-precision system for nuclear simulation.
1954 — EAI 16-31 R; first general-purpose analog computer with miniature tubes and “Time Division” multipliers.
1957 — EAI 131-R; analog computer with automatic output system (AERO).
1958 — Introduction of the EAI 231-R analog computer. This standard computer quickly established itself and proved very popular (over 500 systems still in use). It incorporated automatic digital input/output systems and enabled for the first time higher computing speeds and repetitive operation.
1958 — A smaller version of the 231-R system, the EAI 221-R analog computer, is completed.
1959 — The world’s first fully transistorized desktop analog computer, the EAI TR-10, with 20 computing amplifiers, brings analog computing to the engineer’s workstation.
1961 — The EAI TR-48, a fully transistorized desktop analog computer with 48 computing amplifiers, fills the gap between large installations and small systems, and quickly becomes a standard instrument in industry (over 700 units delivered to date).
1962 — The first standardized hybrid system, the EAI HYDAC 2000, comes to market. It consists of the EAI 231-R analog computer and the parallel logic unit DOS 350.
1963 — EAI 231-R-V; the first analog computer with built-in logic enabling automation of the program sequence.
1963 — Introduction of the EAI HYDAC 2400; the first hybrid system consisting of large-scale standard analog and digital computing systems (EAI 231-R-V and DDP-24 respectively).
1963 — Introduction of the EAI TR-20, a fully transistorized desktop analog computer with 20 computing amplifiers and drawer-mounted function generators.
Over 1600 units of the TR-10 and TR-20 series have been delivered to date.
1964 — The digital expansion system EAI DES-30 provides, in a desktop console, parallel digital components to supplement the newly developed TR-48/58 analog computer (with electronic mode control).
1964 — Development of the EAI 8800 Analog/Hybrid Computer; with 330 computing amplifiers, the largest of its kind. It forms the analog section of the hybrid system EAI 8900 (including the EAI 8400 digital computer) introduced in 1965.
1965 — Introduction of the EAI 680, a hybrid analog computer of medium size (156 computing amplifiers), with 10 V reference voltage. Expandable with the EAI 640 digital computer to form the EAI 690 hybrid system.
1967 — After fifteen years of experience in computer development, introduction of the EAI 580 Analog/Hybrid Computer.
EAI 580 Analog/Hybrid Computing System
The EAI 580 Analog/Hybrid Computer is a desktop computer embodying a completely new concept that closes an existing gap between desktop units and large computing installations.
The idea for the EAI 580 was born from the growing demand for a high-precision medium-sized computer that offers the possibility of expansion into a true hybrid system, yet whose operation can be learned quickly and easily. The result is a compact unit in which the analog section, parallel logic, and interface for coupling to a digital computer can be combined in a single base console with the dimensions of a desktop computer (130 × 75 × 80 cm).
The computing centers of EAI played a major role in the design of the EAI 580 system. Their experience in daily work with analog, digital, and hybrid computing systems is responsible for the development of a unit whose organization is entirely oriented to the needs of the user.
Furthermore, the design was based on a comprehensive study of the wishes and suggestions of existing users of analog and hybrid computing installations. The result is a machine that spares the user a large portion of the deliberation and manual operations involved in programming, so that more attention than before can be devoted to the problem itself.
Key Features of the EAI 580 Analog/Hybrid Computer
- Accuracy: ±0.01% (linear computing components)
- 80 computing amplifiers
- 70 servo potentiometers
- 10 manual potentiometers
- ±10 V reference voltage
- Electronic integration control (via timer and parallel logic)
- Many nonlinear computing components (high-precision multipliers)
- Parallel logic
- Built-in interface
- Optical and acoustic overload indication with automatic program stop
- Static test
Particular emphasis has been placed on flexibility and expandability: all computing components are implemented as plug-in modules; the unit can be delivered as a pure analog computer with individual component complement and expanded at a later date by additional components, by the parallel logic, and — for expansion into a full hybrid system — by an interface. The base console is fully pre-wired for accommodation of all additional equipment.
All integrators can be controlled individually or in groups from the operating panel, from the parallel logic, or from a digital computer. This makes it possible to apply iterative and hybrid computing methods extremely effectively for solving boundary-value problems and partial differential equations. The electronic control and the excellent dynamic characteristics of the components permit high computing speeds (100 µs). The times for “COMPUTE” and “INITIAL CONDITION” can be set independently of each other and continuously to values between 100 µs and 100 s.
EAI 580 Master Control Panel
The EAI 580 is the first desktop computer with servo potentiometer setting. Up to 70 potentiometers can be set via a clear keypad or by a digital computer. In addition, it is possible to “scan through” all potentiometers using a manual switch during the computing run.
The EAI 580 system also contains 10 manual potentiometers.
Particularly useful for the application of iterative and hybrid computing are the Track/Store units. The problem of low-delay tracking with minimum drift during storage has been solved by means of two separate, electronically switched storage capacitors of different sizes.
The standard complement of nonlinear and digital components includes high-precision parabolic multipliers (accuracy ±0.025%), comparators with built-in amplifiers, limiters, and logic units such as counters, gates, flip-flops, registers, crystal-stabilized timers, etc.
Noteworthy is the convenient setting of the diode function generators. They are housed in drawers that can be pulled out for adjustment. The setting of slopes and breakpoints is accomplished with convenient rotary knobs. Additional programming aids such as time base, Track/Store amplifiers for separate setting of breakpoint and slope, and output amplifiers with variable gain are built in.
EAI 580 Advanced Analog and Hybrid Features
The block diagram of the EAI 580 illustrates the system architecture, including:
- Parallel Logic System — parallel logic elements, external logic trunks
- Control Interface System
- Analog Computing Components
- Address and Readout System
- Time Scale Selection System
- Mode Control System
- Analog Computer with data transfer, sensing, storage, decoding, buffering, and steering functions
Information flows as data, control data, and combined data/control.
EAI 580 Coupling to Digital Computers
Standard interfaces are available for coupling to the EAI 640 and PDP-8-S digital computers. However, any other desired digital computer can also be connected on request. The interface enables mode control, addressing of components, and potentiometer setting by the digital computer, as well as data exchange between the analog and digital sections.
The price of the EAI 580 Analog/Hybrid Computer ranges, depending on the component complement, between DM 50,000 and DM 250,000.
The EAI 580 Analog/Hybrid Computer will be available on the German market in November 1967.
Detailed color brochures or technical specifications for the EAI 580 system are available on request. The sales and applications department is available at any time for discussion of further details or for demonstration of the EAI 580.
Attention is drawn to the fact that the EAI 580 system will be exhibited and demonstrated for the first time in the Federal Republic of Germany and West Berlin from October 30 to November 3, 1967, during the “Electronics USA 67” exhibition at the US Trade Center, Frankfurt am Main. A corresponding invitation is enclosed with this report.
Education and Training Services
EAI Analog/Hybrid Computing Course 1967
Date: December 4–8, 1967, in Aachen or Munich.
An invitation is extended to participate in the 12th Analog/Hybrid Computing Course.
The course will take place — not as previously announced in the second week of October — but from December 4–8, 1967. The venue is either Aachen or Munich.
Participants will be given the opportunity to work at the computer themselves within the framework of the practicum. Consequently, the number of participants is limited to 20 persons in the interest of efficiency. Write-ups of the demonstration problems will be given to each participant.
The participation fee is DM 400 per person. For EAI customers who already own an EAI computer, participation for two persons is free of charge. For each additional participant, half the fee is charged.
Registration should be submitted as soon as possible (before October 31, 1967). The number and location of participants will determine whether the course takes place in Aachen or Munich. The participation fee is to be remitted prior to the start of the course upon receipt of confirmation. A place reservation is only possible after payment of the fee.
Course Curriculum
Monday — Introduction, computer organization: fundamental operating principles, control, monitoring. Peripheral equipment: recorders, oscilloscopes, etc. Structure and operating principle of linear and nonlinear computing components: potentiometers, amplifiers, integrators, sample-and-hold units, electronic multipliers, fixed and variable function generators, resolvers, comparators. Practicum.
Tuesday — Introduction to programming techniques: setting up the computing circuit, amplitude and time scaling, static test, treatment of numerical examples. Practicum.
Wednesday — Special applications: simulation of transfer functions, delay circuits, control engineering applications, solution of algebraic equation systems. Introduction to hybrid computing techniques: Boolean algebra; components of parallel logic: AND gates, flip-flops, registers, counters, timers, etc.; control and synchronization. Practicum.
Thursday — Components of parallel logic (continued); applications to digital problems; interface components; multi-speed technique: principle and application for optimization and boundary-value problems; function generation. Practicum.
Friday — Solution of partial differential equations; demonstration of a problem solved using the method of characteristics. Practicum.
The practicums are conducted on the Analog/Hybrid System EAI 580, TR-48/DES-30, and the analog computer TR-20.
(Dipl.-Ing. K. J. Hortenbach, Applications Engineer)
Brush Instruments — MARK 220 Two-Channel Recorder
A new portable two-channel recorder, the MARK 220, by Brush Instruments Division of Clevite Corporation, was presented to the public in the United States in early August 1967.
This is a truly portable device weighing only 11 kg, equipped with two analog channels and all the technical characteristics of Brush recorders that until now were only achieved in expensive units.
- Servo-controlled pen via contactless HF feedback system
- Patented pressure-fluid writing system
- Rectangular coordinate paper
The frequency response is linear and constant up to 100 Hz. The analog channels have a differential input symmetric to ground. Maximum sensitivity is 1 mV/division.
The pen servo system is electrically protected against unintentional overloads. Critical damping enables an optimal step response, so that square-wave signals can be recorded faithfully without rounding of corners or overshoot.
The adjustment arrangement for both channels includes a 14-position input divider, a parallax potentiometer, and an additional potentiometer for continuous setting of intermediate values of the input divider. Two event markers are available at the edge of the analog channels to mark any event during recording. A third center marker can be installed.
The MARK 220 uses the cost-effective “Brush Accuchart” special paper. The paper roll is easily accessible from the front panel. The paper feed speed is electrically selectable at 1, 5, 25, and 125 mm/sec.
The new Brush two-channel recorder MARK 220 is fully transistorized and designed for 110 V/50 Hz or 220 V/50 Hz mains connection.
The price of the Brush recorder MARK 220 is approximately DM 8,000 ex Aachen warehouse. The unit is available for short-term delivery.
A detailed data sheet on this new Brush device is enclosed with this report.
New EAI Digital Voltmeters
EAI Digital Voltmeter Type 6200 (background)
In the previous issue of the report, the new EAI 6200 digital voltmeter was described in detail: a compact, easily transportable small device with integrating operation, 3½-digit display, and printer output. The display unit and power supply are housed in a base enclosure accommodating various plug-in modules for measurement of DC and AC voltages, time intervals, and frequencies.
New Variants of the EAI Digital Voltmeter
The same device is now presented in two further versions:
- Type 6240 as a 19-inch rack-mount module
- Type 6250 as an accessory for desktop computers TR-10 and TR-20
EAI Digital Voltmeter Type 6240
The Type 6240 digital voltmeter is a 19-inch rack-mount version of the Type 6200. Electrically, both units are identical. Both types can be supplied on request with a BCD output for connection to printers, parallel-to-serial converters, remote displays, etc.
Technical Data:
| Parameter | Specification |
|---|---|
| Display | 4-digit, 3 true digits and 1 overflow digit; trigger of display continuously adjustable from 0.2 to 6 sec; automatic polarity indication |
| Measuring range | 100 mV to 1000 V |
| Resolution | 100 µV |
| Accuracy | ±0.1% of full-scale ±1 digit |
| Range overload | 40%, except 1000 V range |
| Input impedance | 10 MΩ, constant |
| Input | Floating or grounded; ±500 V DC allowed between input and chassis ground |
| AC rejection | 80 dB at 60 Hz, 90 dB at 120 Hz |
| Conversion time | approx. 100 ms |
| Response time | For a step input corresponding to the maximum value of the respective voltage range, 99.9% of full-scale is reached after 700 ms |
| Overload protection | Up to 1000 V DC can be applied safely at any range setting (overload indication) |
| Mains connection | 115 V / 230 V ±10%, 50–400 Hz |
| Price | DM 2,475 (undutiable) / DM 2,915 (dutiable) |
As an accessory, an additional 19-inch chassis is supplied into which various add-on units can be inserted. At present, a preamplifier and an AC voltage converter are available; further plug-in modules are under development.
AC Voltage Converter Type 6243 — Technical Data:
| Parameter | Specification |
|---|---|
| Measuring ranges | 1 V rms – 300 V rms |
| Frequency range | 20 Hz – 100 kHz |
| Accuracy | 0.2% for 20 Hz – 10 kHz; 0.3% for 10 kHz – 100 kHz |
| Input impedance | 1 MΩ, 30 pF shunt capacitance |
EAI Digital Voltmeter Type 6250 — Accessory for EAI TR-10 and TR-20 Desktop Analog Computers
The new EAI Digital Voltmeter Type 6250 is a precision unit for the EAI analog computers Type TR-10 and Type TR-20, serving for rapid visual display of analog voltages in digital form. This additional capability shortens problem processing time and increases the readout accuracy of data obtained in the computer. Its high conversion speed permits rapid reading of slowly varying voltages and significantly reduces the time required to manually set potentiometers and function generators. Its high input impedance permits accurate reading of output voltages and potentiometer settings without loading errors.
Relative errors between the reference voltage of the digital voltmeter and the analog computer are eliminated by the CALIBRATE mode, operated by a pushbutton on the digital voltmeter; the digital voltmeter full-scale is thereby aligned to the ±10 V computer reference.
In its external dimensions, the Type 6250 digital voltmeter matches the dimensions of the TR-10 and TR-20 computers, so that it can be placed on top of their enclosures. The voltmeter is held in place by permanent magnets. No mechanical modifications to the computer, such as drilling of holes, are required; only a connector with six connecting wires is installed at the rear.
Technical Data:
| Parameter | Specification |
|---|---|
| Voltage range | 3.1 V and 10 V full-scale |
| Accuracy | ±0.1% |
| Voltage overload | 40%; maximum displayable value 13.99 |
| Input impedance | 10 MΩ, constant |
| Overload protection | Without damage to the unit: 1000 V on any range (with overload indication) |
| Conversion time | 100 ms |
| Display time | Variable from 0.2 to 6 sec, plus HALT |
| Response time | 700 ms for full-scale step at input |
| Polarity | Automatic display of ”+” and ”−“ |
| Noise rejection | 80 dB at 60 Hz (common-mode and series noise) |
| Price | DM 2,230 (undutiable) / DM 2,625 (dutiable) |
EAI PACE TR-20 Desktop Analog Computer
Fully transistorized, equipped with 20 computing amplifiers, 24 coefficient potentiometers, and a range of nonlinear components; provided with a high-speed repetitive system enabling automatic iterative computing; interchangeable patchboard; etc.
EAI Electronic Associates GmbH, 51 Aachen, Bergdriesch 37 Tel. (0241) 28021/22 — Telex: EAI Aachen No. 832676