The EAI 180 Analog/Hybrid Computing System — Product Brochure

This document is an English translation of the original German-language brochure “Das EAI 180 Analog/Hybrid-Rechensystem” published by EAI Electronic Associates GmbH, Aachen.

A NEW ANALOG/HYBRID COMPUTER

It is well known that EAI, the world’s leading manufacturer of analog/hybrid computers, offers customers a wide range of analog computers to choose from.

The range extends from the most widely known desktop analog computer TR-20 with a maximum of 20 computing amplifiers, through the EAI-380, TR-48, EAI-580, EAI-680, EAI-7800, up to the EAI-8800 with approximately 348 computing amplifiers. All of these computers can be expanded into analog/hybrid computers by means of parallel logic. The accuracy of the linear components of these computers is on the order of 0.01%.

Market research revealed that even this broad range of instruments did not satisfy all customer requirements. There was a lack of a small unit that, at somewhat lower accuracy and component density, would offer the same technology as the larger EAI analog/hybrid computers. Such a unit should give the user a first step into analog computing at a favorable price, without having to sacrifice operating convenience, clarity, and versatility. From this need the EAI-180 analog/hybrid computer was developed.

System Composition

The system consists of:

Analog section:

12 summers, of which 6 are switchable as integrators
8 potentiometers
Additionally: multiplier, fixed and variable diode function generators, function switches, free elements, comparators, electronic switches, etc.

Logic section:

AND/NAND gates
Flip-flops
Counters (BCD and binary)
Indicators and switches
Digital clock

Multiple EAI-180 units can of course be connected in parallel to increase computing capacity. It is also possible to couple the EAI-180 with existing EAI analog/hybrid computers.

Through the use of the most modern integrated circuits, a compact unit has been developed that, with adequate capacity, is also suitable for lecture and demanding laboratory use. In designing the exterior, particular attention was given to clear presentation and separation of the computing components.

Through careful pricing it should be possible to deploy the EAI-180 even where financial constraints have until now prevented this.

EAI is convinced that this unit will be received with as much enthusiasm in the fields of research and education as the other analog computers, since more than 3000 EAI analog computers are already in service.

SPECIAL FEATURES OF THE EAI-180

Construction: Like the larger EAI computers, the EAI-180 was also built using plug-in card technology. To construct a cost-effective, service-friendly unit, as many printed and integrated circuits as possible with convenient plug-in connectors were employed.

Safety: To ensure the safety of untrained personnel, the computing voltage is 10 V. In addition, various precautionary measures were taken to protect the electronics against overloading and short circuits.

Compatibility: Since thousands of EAI desktop analog computers are already in worldwide use, the EAI-180 was designed so that the same patch cords as those used with other EAI desktop analog computers can be used. Compatibility of the patch panels was also ensured. Besides the fact that beginners can thereby more easily transition to larger machines, continuity is achieved when reading the various EAI reports and operating manuals.

Mode Control: In order to make the best possible use of the logic of the EAI-180, the control of analog operating modes — initial conditions, hold, and compute — is accomplished purely electronically. In addition, it is possible to control each integrator individually.

Repetitive Operation: The timer for repetitive operation provides logic output signals corresponding to the respective states “Compute” and “Initial Condition.” Furthermore, the timer provides a sawtooth voltage from 0 to 10 V, which can be used as the time sweep for a connected recorder or oscilloscope.

Clocked Logic: Apart from the gates, all logic components are clocked, so that the user need not spend time on considerations regarding rise times and propagation delays.

BRIEF SPECIFICATIONS

I. GENERAL

Parameter	Value
Supply voltage	220–260 V
Frequency	50 Hz
Power consumption	approx. 30 W
Dimensions	approx. 64 × 40 × 30 cm (24″ × 16″ × 12″)
Reference voltage	+10 V and −10 V, ±0.1% at 50 mA
Repetitive operation timer	1 ms to 10 s
Null meter	50 µA; ranges +1 V to 30 V (full scale)
Digital voltmeter	3½-digit (option)
Null potentiometer resistance	5 kΩ
Null potentiometer linearity	±0.1%
Null potentiometer type	10-turn, wire-wound
Function switch positions	3
Function switch operation	Manual, individual, visual
Overload recovery	Fast recovery from overload

II. ANALOG COMPONENTS

1. Operational Amplifiers

Parameter	Value
Output voltage	±11 V at 5 mA
Offset voltage	<5 mV
Bandwidth	100 kHz min (at gain factor 1)

1.2 Summers

Parameter	Value
Number of ×1 inputs	2
Number of ×10 inputs	2
Resistors	3 × 1 MΩ, 2 × 100 kΩ
Precision	0.25%

1.3 Integrators

Parameter	Value
Resistors	2 × 1 MΩ
Capacitance	1 µF; 0.1 µF option
Precision	0.25%
Drift (initial condition, hold)	max. 1 mV/sec
Individual mode control	possible

2. Potentiometers

Parameter	Value
Resistance	10 kΩ
Type	Carbon or wire-wound

3. Nonlinear Elements

3.1 Multiplier (with built-in inverters and output amplifiers): Accuracy 2%
3.2 Variable diode function generator: 4 or 10 segments
3.3 Comparators: Electronic type

4. Free Elements

Resistors
Capacitors
Diodes, Zener diodes

III. LOGIC COMPONENTS

Parameter	Value
Clock frequency	1 Hz to 10 kHz
Operating modes	Run, Stop, Clear (pushbuttons)

Components:

3.1 AND/NAND gates with inverted outputs
3.2 Flip-flops
3.3 4-bit binary counters
3.4 4-bit BCD counters
3.5 Indicators
3.6 Switches

APPLICATIONS

This new analog/hybrid computer, the EAI-180, is intended primarily to serve two purposes in educational institutions and industry.

The first is to place in the hands of educational staff an extremely cost-effective unit with which students can be trained in the operation of both pure analog computers and analog/hybrid computers. The use of the EAI-180 allows a maximum number of students to be thoroughly trained with a minimum of financial outlay. Any larger installations already in place can thereby be kept free for advanced courses and special research projects.

A further purpose the unit can serve is as an instructional aid across many disciplines. By equipping the EAI-180 with a display, the explanation of a difficult-to-grasp phenomenon can be visualized — something that is often not easy without this visual representation. One might think, for example, of the effect on a chemical reaction when increasing quantities of a catalyst are added.

In research establishments and industry, the EAI-180 can also serve to test solution approaches for specific sub-problems of larger simulation tasks, without consuming expensive machine time on larger installations.

A further application is the testing of integrated circuits, where the entire circuit in which the IC is to be used is simulated on the computer.

TECHNICAL SUPPORT

As a purchaser of an EAI-180 analog/hybrid computer, the following services are available:

Courses: EAI regularly conducts courses in Europe for the operation and maintenance of analog, analog/hybrid, digital, and hybrid systems. Customers benefit from more than 20 years of experience in the design and application of modern computing systems.

Application Studies: The application studies collection currently comprises approximately 500 titles from 34 subject areas (e.g., aerospace, bio-medicine, chemistry, control engineering, and others).

Consulting: The staff at the computing centers and applications laboratories possess a wealth of experience, continuously supplemented through collaboration with scientists from the most varied academic disciplines. EAI is therefore confident of being able to provide the best possible advice and support in solving specific problems.

OUTPUT DEVICES (DISPLAYS)

EAI offers a range of high-quality output devices for the EAI-180 analog/hybrid computer from its production and distribution program:

EAI XY Recorder VARIPLOTTER: EAI manufactures 8 different XY recorder VARIPLOTTER models, namely models 1110, 1125, 1130, 1131, 1132, 1133, 1136, and 205 S/T. Corresponding data sheets are available on request.

EAI 2-Channel Strip Chart Recorder 8870: An excellent output device that allows the recording of 2 analog measured quantities with a recording width of 2 × 40 mm. The unit also has 2 event markers and provides clearly defined measurement curves with a nonlinearity of less than ±0.5%. Data sheets available on request.

Oscilloscope HM 312/3: A general-purpose oscilloscope with stable triggering and relatively high measurement accuracy. The usable screen area within the rectangular graticule is 8 × 10 cm. As a display device, the HM 312/3 is a valuable addition to the EAI-180.

EAI PRODUCT LINE

EAI Analog Computers

EAI-680 Analog/Hybrid Computer: Fully transistorized, electronic mode control; 204 computing amplifiers, 120 servo potentiometers, nonlinear components, parallel logic, 10 V reference voltage, interchangeable problem board.
EAI-580 Analog/Hybrid Computer: Fully transistorized, electronic mode control; 120 computing amplifiers, 70 servo potentiometers, nonlinear components, parallel logic, 10 V reference voltage, interchangeable problem board.
EAI-380 Analog/Hybrid Computer: Fully transistorized, electronic mode control; 31 computing amplifiers, 36 coefficient potentiometers, nonlinear components, parallel logic, 10 V reference voltage, 3 interchangeable problem boards.
EAI TR-48/58 Desktop Analog Computer: Fully transistorized, electronic mode control; configured with 58 computing amplifiers, 60 coefficient potentiometers, a range of nonlinear computing components, interchangeable patch board.
EAI TR-20 Desktop Analog Computer: Fully transistorized, equipped with 20 computing amplifiers, 24 coefficient potentiometers, and a range of nonlinear components; interchangeable patch board.
EAI TR-8 Small Analog Computer: In 19-inch plug-in card technology. For building specialized analog computing systems with PACE TR-20 computing components.
EAI Process Analog Computer PC-12: An extremely flexible, fully transistorized analog computer for industrial process control.
EAI Digital Extension System DES 30: Add-on unit for EAI analog computers type TR-48/58 and TR-20. The system contains AND gates, monostable timers, differentiators, counters, flip-flops, registers, etc.

EAI Digital Computers

EAI A10 Digital Computer: Word length 16 bits + memory protection bit; cycle time 1.05 µs; core memory capacity 8–32K. Hard-wired multiplication, division, and square root. Extensive software.
EAI Universal Digital Computer Type PDS 1020: General-purpose digital computer; runtime memory with 4096 words × 16 bits plus sign; input via paper tape or keyboard; output via paper tape or electric typewriter; simple programming through INTERPRETER language; desk-size (mobile).

EAI Hybrid Systems

EAI-390: Consisting of analog/hybrid computer EAI-390, digital computer EAI-640, and interface. Specialized hybrid software.
EAI-590: Consisting of analog/hybrid computer EAI-590, digital computer EAI-640, and interface EAI-693. Specialized hybrid software.
EAI-690: Consisting of analog/hybrid computer EAI-680, digital computer EAI-640, and interface EAI-693. Specialized hybrid software.