English translation
EAI Report No. 010 — Newsletter of EAI Electronic Associates GmbH, Aachen (January/February 1967)
This document is an English translation of the original German-language EAI-Report Nr. 010, January/February 1967, published by Electronic Associates GmbH, Aachen.
Staff Organization Announcement
EAI-PAC-b NEWSLETTER
EAI Electronic Associates GmbH, Aachen, Bergdriesch 37 January/February 1967, No. 010
Staff:
- K.J. Hortenbach — Applications Engineer / Sales Engineer, Aachen
- A. Bento — Sales Engineer
- H.W. Bock — Sales Engineer II
- [Sales territories shown on map: Hamburg, Düsseldorf, Köln, Frankfurt, Berlin, München]
- B. Krüger — Berlin
- V. Koch — Sales Engineer III
- E. Roth — Sales Engineer IV, Munich
- D. Schwarz — Head of Customer Service
- U. Keck — Service Engineer
- J. Stute — Service Engineer
1966 was so successful for EAI Electronic Associates GmbH that the decision was made to further expand the technical departments starting January 1967.
As shown in the enclosed overview, starting January 1967 six consulting engineers will be active in the Federal Republic of Germany and West Berlin:
Sales Territory I: Dipl.-Ing. Alberto Bento (Aachen)
Sales Territory II: Dipl.-Ing. Hans-Werner Bock (Aachen)
Sales Territory III+B:
- Ing. Volker Koch (Berlin)
- Dipl.-Ing. Burkhard Krüger (Aachen/Berlin)
Mr. Krüger is a scientific assistant at the Technical University of Berlin and works as a freelancer for EAI GmbH in West Berlin. Mr. Krüger will be available for both service purposes and, in urgent cases, for consultation with Berlin business contacts. Dipl.-Ing. B. Krüger, 1000 Berlin 42, Oberlandstrasse 101, can be reached by telephone at Berlin / 31 07 81 / Ext. 403 at the Technical University of Berlin.
Sales Territory IV: Erwin Roth, 8034 Munich-Germering, Parsbergstr. 8, Telephone: Munich (0811) 87 34 57.
Mr. Roth, in addition to his consulting work in Sales Territory IV, is responsible (in cooperation with the Aachen customer service laboratory) for EAI customer service in Sales Territory IV and the Stuttgart area. Mr. Roth resides in Munich, where he maintains a small stock of the most important EAI-Brush spare parts. Southern German business contacts can reach Mr. Roth daily at telephone: 0811 / 87 34 57.
Sales Territory A (Aachen): Dipl.-Ing. Klaus-Jürgen Hortenbach (Aachen).
Mr. Hortenbach heads the EAI GmbH Applications Department and is available to all EAI GmbH business contacts for specialized technical consultation. In addition to these duties, Mr. Hortenbach is responsible for advising EAI customers in and around Aachen.
The EAI GmbH Customer Service Department in Aachen is led by Ing. Dieter Schwarz and handles all service work for EAI and Brush equipment in the Federal Republic of Germany and West Berlin. Mr. Josef Stute is responsible for customer service in Sales Territory I and North Rhine-Westphalia; Dipl.-Ing. Ulrich Fleck is responsible for customer service in Sales Territories II and III. Customer service in Sales Territory IV and the Stuttgart area is handled by Mr. Dieter Schwarz and Mr. Erwin Roth.
The company hopes that through this reorganization it will achieve more effective cooperation with its business contacts.
Yours faithfully, EAI Electronic Associates GmbH (Henk W.A. Jungbauer) Managing Director
Education and Training Services
EAI Analog Computing Courses 1967
Dates:
- 1–3 March 1967: Introduction Course
- 6–10 March 1967: Analog/Hybrid Course
Both courses take place Monday through Friday at the Astoria Hotel, Bad Aachen.
Participants are invited to attend one of the above analog computing courses.
The Introduction Course lasts only three days and is limited to conveying the basic principles of analog computing. It is intended for participants who have not previously been involved in analog computing and work in other fields.
The five-day Analog/Hybrid Course also covers basic concepts, though in somewhat less detail. The main emphasis here is on hybrid computing.
In both courses, participants are given the opportunity to work directly on the computer. Consequently, the number of participants is limited to 20 persons per course to ensure effectiveness. Writeups of the demonstration problems are distributed to each participant. Practical exercises are carried out on the EAI Analog Computer TR-48 and TR-48/DES-30.
Fees:
- Introduction Course, 1–3 March: DM 200.- per person
- Analog/Hybrid Course, 6–10 March: DM 400.- per person
For EAI customers who already own a computer, participation for 2 persons is free of charge; for each additional participant, half fees are charged.
Interested parties are requested to submit a registration soon. The course fee should be transferred upon receipt of the confirmation, before the start of the course. A place reservation is only possible after payment of the fee. Hotel reservations can be made on request.
Program: Introduction Course in Analog Computing
Day 1 (Monday): Introduction: Purpose of the analog computer, organization of analog computers — Principles of operation, control, monitoring. Peripheral devices: recorders, oscilloscopes, etc. Construction and operation of linear computing components: potentiometers, amplifiers, integrators.
Day 2 (Tuesday): Solution of simple differential equations. Construction and operation of nonlinear computing components: multipliers, resolvers, function generators, comparators.
Practical session: Solution of simple ordinary differential equations. Solution of differential equations of higher order. Solution of differential equations with variable coefficients. Investigation of simple physical systems. Function generation. Special circuits with computing amplifiers. Analog storage. Simple iterative programs.
Program: Analog/Hybrid Computing Course
Monday: Introduction, computer organization — principles of operation, control, monitoring. Peripheral devices: recorders, oscilloscopes, etc. Construction and operation of linear and nonlinear computing components: potentiometers, amplifiers, integrators, sample-and-hold units, servo multipliers, electronic multipliers, fixed and variable function generators, resolvers, comparators.
Practical session.
Tuesday: Introduction to programming technique: setting up the computing circuit, amplitude and time scaling, static test. Treatment of numerical examples.
Practical session.
Wednesday: Special applications: simulation of transfer functions, delay circuits, control engineering applications, solution of algebraic equation systems.
Introduction to hybrid computing: Boolean algebra. Components of parallel logic: AND gates, flip-flops, registers, counters, timers, etc. Control, synchronization.
Thursday: Parallel logic components (continued). Applications to digital problems. Interface components. Multi-speed technique: principle and application for optimization and boundary-value problems. Function generation.
Practical session.
Friday: Solution of partial differential equations. Demonstration of a problem solved using the method of characteristics.
Practical session.
Practical exercises are carried out on the Analog-Hybrid System TR-48/DES-30.
(K.-J. Hortenbach, Applications Engineer)
News From: Electronic Associates Inc. — European Division
Centre International 2, 2nd Floor, Place Rogier, Brussels, Belgium Telex: 2.21.10 — Telephone: 18.40.04
EAI 640 Digital Computing System
Balance in Versatility and Economy in Hardware and Software
EAI Electronic Associates Inc. introduced its new, very fast binary digital computer, the EAI 640, at the end of 1966. After the larger system EAI 8400, this is the second general-purpose digital computer built by EAI in the last two years.
The EAI 640 is ideally suited for a wide range of technical and scientific applications. It includes new input/output and interrupt capabilities that allow optimal use not only as a pure digital computer but also in hybrid or special data-processing systems. The computer is built from integrated circuits.
The fixed word length of the EAI 640, the same for data and instructions, is 16 bits with an additional memory protection bit. Further highlights include: maximum core memory capacity of 32,768 words; cycle time of 1.65 µsec; instruction set of 62 instructions; multi-level program interrupt system; capability to connect up to 64 peripheral devices. The maximum I/O transfer rate is 1.2 million 8-bit bytes/sec.
In addition to the basic system with 4K core memory, the EAI 640 can be expanded to 8K, 16K, or 32K; furthermore, a direct memory access channel can be added, which is unusual for computers in this price class.
Available peripheral devices include: a cost-effective disk storage unit with a maximum capacity of 1/4 million words; a line printer — 300 lines/min; high-speed paper tape reader and punch at 300 and 120 characters/sec respectively; a card reader — 400 cards/min; a card punch — 100 cards/min; a magnetic tape unit with a transfer rate of 36 kHz.
The EAI 640 software library contains a symbolic assembler, FORTRAN (ASA Standard), Linking Loader, Debug, Update, Bootstrap, an operations interpreter, and other hybrid programming systems.
A more detailed report on the EAI 640 will appear in the next issue of the EAI Report.
(Volker Koch, Sales Engineer)
Recording Rapidly Repetitive Computing Runs with a Coordinate Plotter
There is often a desire to record a solution curve obtained from the analog computer in repetitive mode — displayed on an oscilloscope — also using a coordinate plotter (X-Y recorder). Since a coordinate plotter can only process very low frequencies, direct recording is not possible. In many cases, especially with simple problems where the computation time is not critical and can be freely chosen, the computer will be operated slowly (non-repetitively) for recording the solution. In some circuits, however, the computation time is fixed and amounts to only a few milliseconds — for example, when using subroutines, boundary-value problems, etc.
A method is described here that makes it possible to record a rapidly running solution function point-by-point through a coordinate plotter using a sample-and-hold circuit.
The mode of operation is explained with reference to Figures 1 and 2 for a simple exponential function. The function to be recorded, f(τ) = Ae^(−τ/T), obtained in repetitive mode, is applied to the input of a track-and-store (T/S) unit. The operation of a T/S unit was already discussed in detail in EAI Report No. 007, May–June 1966, and is assumed to be known here. Instead of the T/S units used here — available in the plug-in unit of an electronic comparator — standard integrators may also be used, though at the cost of a larger time constant. (The minimum time constant is 10 µsec for the T/S unit and 100 µsec for the integrator.)
The switching of the T/S units between “track” and “hold” is accomplished by binary commands from the comparator. In the comparator, two input voltages are compared with each other. If their sum is greater than zero (more precisely, greater than 1 mV), a binary 1 appears at the output, switching T/S 1 to “hold” and T/S 2 to “track.” If the sum is less than zero, conditions are reversed. The comparator input voltages are two ramp functions. Integrator 2 generates a repetitive rising ramp corresponding to the computing time τ. Integrator 3 is switched to “store,” i.e., it operates continuously in the “compute” state. It generates a slowly falling ramp corresponding to the recording time t (drawn in Figure 2 as rising for clarity). At the moment when t = τ, the comparator switches the storage unit, which holds the corresponding instantaneous value of f(τ). The function f(τ) thus transforms into f(t). It is taken as a staircase approximation at the output of T/S 2 and fed to the Y-input of a coordinate plotter. The X-input of the coordinate plotter is connected to the output of Integrator 3.
As can be seen from Figure 2, the more gently the slope of t, the more curve points are sampled. It is therefore possible to make the steps of the solution curve so small that they are no longer visible. It should be noted, however, that the sampling points must be more densely spaced the higher the frequency components contained in the function f(t).
This circuit can also be used effectively for function generation. If, instead of the ramp τ, an arbitrary function f(t) is applied to the comparator, the output of T/S 2 yields f(τ) with τ = f(t). Using this so-called subroutine technique, functions of three to four independent variables can be generated by temporal interleaving of additional partial programs.
Several applications of the subroutine technique will be described in subsequent issues of the EAI Report.
Brush Recorder Mark 250 — Versatile 4½” Strip Chart Recorder
The new Brush Recorder Mark 250 is a single-channel recorder in a compact design. Due to its versatility, it can be used universally in the laboratory, test field, medical research, and in recording arbitrary quantities for monitoring industrial process sequences, to name only a few examples.
The Mark 250 can be used with particular success in applications where high response speed is important. The rise time for a voltage step at the input is 40 ms for 1% to 99% of full channel width. With full use of the entire writing width (114.3 mm), the frequency response is flat up to 10 Hz.
The very low nonlinearity of less than 0.5% is attributable to the special type of pen deflection. This deflection system consists of a closed control loop in which the pen position is measured by a displacement transducer with an accuracy of 0.1%. The Brush Metrisite displacement transducer operates without friction, without brushes or other contacts, so that accuracy does not degrade through wear or contamination even after extended use.
The recorder owes its versatility to the fact that all preamplifiers, etc., can be exchanged. 21 different fully transistorized plug-in units are available: DC preamplifiers with sensitivities from 1 µV to 50 V/division; phase-sensitive demodulators; carrier frequency amplifiers; logarithmic plug-ins; as well as plug-ins for measuring frequency, power, current, and AC voltage. These units allow the system to be easily expanded and adapted to the respective application.
The lateral movement of the writing pen is rectilinear, so that paper with a right-angle coordinate grid can be used for recording. Since the ink system is pressurized, the ink is pressed into the paper during the writing process. This results in a very uniform and clean line, which is completely smear-proof within seconds after registration. Another outstanding feature of this device is the removable paper cassette. The user thus has the ability to remove the entire recording and evaluate it elsewhere. Rotary knobs allow any desired point on the curve to be conveniently located by hand. By turning back to a previously defined starting point, another curve can be superimposed on the original recording. The writing table of the paper cassette can be tilted 45°, which facilitates viewing the recording and making handwritten notes during the writing process.
Twelve paper feed speeds can be selected using push buttons. The speeds are synchronized with the mains frequency. The perforation on both edges drives the paper without slippage, thus avoiding accumulative errors in paper advance.
Please request detailed data sheet and price.
Brush Recorder Mark 250 — Model 15-6317-00 Portable
Specifications:
- Span: 4½” calibrated chart
- Response: 40 milliseconds full scale
- Nonlinearity: ½% of full scale
- Trace Presentation: Rectilinear
- Trace Width: 0.01” nominal
- Marking Method: Pressurized Fluid
- Marking Fluid Capacity: 2 oz. (Sufficient for one year of normal recording); replaceable cartridge
- Chart Description: 4½” grid, graduated in 50 divisions across span. Graduated in 1/10” increments (1/2” and 1” accentuated) on time axis. Right and left event marker channels.
- Chart Capacity: Hi-contrast — 100’; reproducible — 150’
- Chart Speeds: 0.1, 0.2, 0.5, 1, 2, 5 inches/min and inches/sec
- Chart Speed Accuracy: Sprocket drive, line synchronized. Speed error non-accumulative.
- Chart Takeup: Internal within chart magazine; chart may be fed externally
- Basic Sensitivity (Without Preamplifier): ±100 mV/div, 50 K input impedance, single ended
- Power Input: 115V (±10/6%), 60 cps, 100 watts max.
- Weight: 65 lbs.
Units for 230/115V, 50 cps operation available, model 15-6317-06.
Signal Conditioners (choice of):
- Signal couplers (50 mV/div., 50K)
- DC Preamplifiers (1 microvolt/div. or 100 microvolt/div.) with or without calibrated zero suppression
- Carrier-Strain-Gage (2 kc)
- Demodulator (60 cps to 10 kc reference or 60 & 400 cps reference)
- Log/Linear
- Converters: frequency deviation, amps, watts, or AC volts to DC volts
Standard Complement Includes: Oscillograph, drive amplifier, pen motor and pen; chart magazine, 1 roll chart paper; inking system; 2 oz. marking fluid.
Highly Stabilized Transistor Power Supplies — All Silicon Technology — 2-Year Warranty
EAI GmbH Aachen is pleased to announce that as of 1 January 1967 it has taken over distribution in the Federal Republic of Germany and West Berlin of the highly stabilized transistor power supplies manufactured by:
G. Polz & Co., Electronic Measuring Equipment 8050 Türkenfeld/Bruck-Emmering, Mitterfelweg 14 Telephone: 08141 / 21 60 or 0811 / 55 70 60
The company POLTRON offers a standard product range SBN — Stabilized Transistor Operating Power Supplies — for voltages up to 300V and currents up to 100A in a power range from 30W to 3 kW.
A detailed data sheet for Poltron transistor stabilized power supplies is enclosed with this EAI Report. A favorable quotation and further technical details will be gladly provided on request.
EAI Variplotter
A wide variety of X-Y plotters, to permit every user to meet exact requirements. All utilize all-solid-state circuitry, simple single-loop drive systems, and rugged high-quality components throughout to provide the finest in recording equipment at moderate prices.
Models available: Series 1110, 1125, 1130, 1131, 1132, 1133, Series 1120, Series 205, Series 99-361.
EAI Electronic Associates GmbH, 51 Aachen, Bergdriesch 37 Tel. (02411) 260 41/42 — Telex: EAI Aachen No. 832676