Analog Computer Do 80

This document translates the original German/English bilingual product brochure published by Dornier System GmbH. The original is in both German and English (parallel columns); this translation reproduces the English content faithfully and supplements it with any German-only material.

1. General

The DORNIER 80 is a compact 10 V desktop analog computer. Its small dimensions (19” standard casing) make it a transportable desktop computer. The computer is stackable with other 19” equipment.

The patch panel layout corresponds to that of bigger computers; the possibilities for flexible wiring of the computing elements are similar. The DO 80 differs from common instructional computers in so far as it permits advanced training and test over or up to large computers. The exchangeable patch panel was dispensed with for reasons of cost; such panels are indeed not customary with computers of this price class.

2. Computer Set-Up

The four potentiometer modules are located above the patch panel. Each module contains the pertinent patch panel segment. On the right-hand side is located the control module with the indicator and control panel. External operation of the control module is possible via adapter cables for the purpose of maintenance and repair.

On the rear are located the connectors for parallel operation of two computers, control signal terminations, mains fuse, and the mains supply. The termination of the internal supply lines is also located on the rear.

3. Description of Control and Indicator Elements

The individual control and indicating elements have the following functions (see illustrations on front and rear views):

Balancing potentiometer for +10 V reference voltage
Balancing potentiometer for −10 V reference voltage
Lamp panel to indicate the state of the maximally loaded computing element
Overload indicator panel. Overload of the amplifiers indicated in the module is indicated simultaneously. A green indicator light shows when the reference voltages are indicated simultaneously.
Analog voltmeter with switchable measurement ranges
(OT) overload holds switch. If the switch is thrown, the hold mode is automatically set in case of an overload.
Twelve-Position selection switch for analog voltmeter. The following can be measured by means of this switch:
- the supply voltages
- the voltage applied on the green socket (7), which is connected to the first thirteen positions: at +10, −10, ±15 V
- at +1: 1.5 V full scale
- at +10: 15 V full scale
- at 100: 150 V full scale
Setting potentiometers for the computing time in the repetitive operation mode and a 1× compute (1×) mode. The product from potentiometer setting to the number of positions is the computing time, and thus the time during which the computer is in the computing state during “repetitive computation.”
Selector switch for rough setting of compute time. The compute time may be varied by the setting of potentiometer 10 and the switch 11 according to the following table:

Position	IC time	Compute time
0.1 sec	0.1 sec	0.1 / 1.1 sec
1 sec	0.1 sec	1 / 11 sec
10 sec	1 sec	10 / 110 sec

Setting potentiometer for IC time. The IC time tp indicated in position 11 applies when the potentiometer 12 is set to its max. position in counter clockwise direction. It may be decreased from this value via the multi-turn potentiometer. IC and compute time are decreased via button 21 to a tenth of the values set. The settable IC time, realized by the potentiometer, may be especially profitable in case of an operation of complementary integrators.
REMOTE control switch. By setting this switch, the DO 80 may be operated as a slave to another DORNIER computer. The timer of a slave computer remains separately functional and may be set as usual via the buttons 15 to 21. A further independent clock is thus available.
IC-MODE indicator. This lamp illuminates if a DORNIER 80 is operated as a slave computer.
Function switches and buttons:
- (HT) Hold button. By pressing this button the computer is set to the IC mode (initial condition) during which all normally controlled integrators build up their initial conditions.
The DR (operate) and HT (hold) buses in the lower part of an integrator module are switched to relay ground via transistors, depending on the mode. The individual modules are decoupled via diodes. The following is valid for the buses in the IC mode:
- DR → transistor cut off
- HT → transistor conducting (relay ground)
- (HT with HOLD). If the HT button is pressed and “HOLD” and DR “with HOLD”, the timer output (ramp) is stopped at +10 V. This may be of service if in the 1× mode with external X-Y plotters. In the IC mode the timer produces a repetitive ramp, increasing during computing time from −10 V to +10 V. By pressing the DR button again, the machine goes back to −10 V.
- (DR) button. This button selects the “computing” state, i.e. a computation is started. The further sequence depends on the mode pre-selection via the push buttons 18 and 19. If neither the 1× button is pressed nor the RR button, the computer goes to the operative mode. In this mode the timer produces a repetitive ramp, increasing during compute time from −10 V to +10 V. By pressing the DR button again, the DR and HT signals become identical. This corresponds to the multi-turn potentiometer. IC and compute time are decreased.
- (mHT) with HOLD button. By pressing the mHT button, the computer is held in the computing state; their instantaneous output voltages being maintained. Computing from the HD mode may be continued by pressing the DR (17) button.
- (AB) Overload holds switch.
- (HT) button — integrator Hold.
- (DR) — Operate; button 17.
DR button. This button selects the “computing” state.
(mHT) button.
1× (compute one x) button.
DR (operate) button.
RR button. The “repetitive operation” mode may be pre-selected via this button. The compute and initial condition modes are then cyclically activated. In this position the computer generates a single ramp—increasing from −10 V to +10 V during computation—which, during IC time, decreases linearly to −10 V.
AB button.
Timer/AB.
1/10 button. Pressing this button reduces the IC and compute times by a factor of 10. The computer time is accelerated by a factor of ten.

4. Descriptions of Computing Elements

Each computing element consists of a printed circuit board, to accommodate the components, and of the patch-board segment rigidly fixed to the PC-board.

Owing to the identical wiring of all 16 computing element slots, every element may be employed on any of the locations.

The following three modules are currently available:

module with one integrator
module with three summers
module with two complete multipliers and two additional summers
module with dead time delay generator
module with AND/NAND gates
module with three flipflops and one monoflon
module with two counters and one timer
module with one timer and two counters

Module with One Integrator

The circuit of an integrator and its patch-board connections are shown on the illustration overleaf. Modes and time constants of each integrator may be selected separately. The mode of this integrator is effected via the buttons T1/10 button.

The capacitors are: 1 µF, 0.1 µF, 0.01 µF.

If the terminations HT and H as well as S and DR are connected on the control panel of an integrator, the mode voltages may be released as by pressing the buttons. This permits an uncomplicated remote control of the computer. If the H termination is connected on the patch panel to the summing junction the integrator is used as a summer by jumper-wiring the terminations marked with E.

Module with Three Summers

Each summer unit contains three summers, the upper one of which works with a feedback and two gain-one inputs. The central summer is a gain-of-ten as well as an available summer. The lower summer requires an externally programmable feedback and can also be operated with gain-of-0.1 inputs. Each summer is an externally programmable feedback and may also be operated with gain-0.1 inputs. A further independent counter is also available.

Module with Two Multipliers and Two Summers

The multiplier module includes two multipliers and, in addition, two summers. To operate the multipliers, the Z input must be wired in such a way that, in case of a division, the output must be jumpered to the Y input.

Potentiometer Module

The following illustration shows patch panel segment belonging to a potentiometer module.

The terminations are identified as follows:

T1, T2: Trunks to rear of computer
E1, E2: Comparator inputs
RTR: Reset-input (TTL-level)
HAND: Logic output of a function switch
SP-A, SP-B: Reference voltage terminations
P1, P2, P3: Setting potentiometers
P4: Ganged potentiometer
black: Signal ground terminations

The upper relay is directly connected with the comparator output. The switch has setting potentiometers for summing junction and for amplifier to be limited by A and B respectively.

Module with One Death Time Delay Generator

This module simulates the transfer function F(s) = e^(−sT). It comprises of an analog-to-digital converter, a shift register, and a digital-to-analog converter. The generator operates either on an external clock pulse or with an internal clock pulse, voltage-controlled oscillator. The oscillator frequency is accelerated by a factor of 10 if the T1/10 button is pressed.

The death time delay generator has an individual mode control. Normally the mode is selected by the DR and HT buttons by pressing DR (button 17) and DR (mode). The compute and initial condition modes are available after pressing DR.

Module with Five AND/NAND Gates

The module has five inputs, a true output and a false output. The outputs of two gates may be connected for wired AND.

Module with Three Flipflops and One Monoflop

The flipflops are designed as RS-flipflops with a clock input. True and false outputs are terminated at the patch panel. Flipflop status is indicated by LEDs. The maximum time can be extended to 1 s by a 10 s external input. The maximum time may be extended further by connection of another counter.

Module with Two Counters and One Timer

The counters are designed as 4-bit binary counters. The counter outputs are indicated by a LED register. A decimal coding of the counters is possible via accessing the first three patch panel positions respectively. Both counters can be reset at the patch panel.

Counters and timer have an individual mode control. Normally the timer is started and the counters are started also. If the computer goes to AB mode (initial position), the timer is started and the counter contents are reset to zero.

Logic Components

All logic components are protected at their outputs against shortage and back-voltage.

5. Patching Examples

The following gives some examples of uncomplicated computing circuits and the appertaining patch panel wiring:

Integrator example 1: Y = −X₀ − ∫(X₁ + X₂ + 10X₃) dt
Integrator example 2: Y = −X₀ − 10∫(X₁ + X₂ + 10X₃) dt
Summer (H = open): Y = −[X₁ + X₂ + 10X₃]; Y = 0 for H = grounded
Summer module (three summers): Y₁ = −(X₁ + X₂); Y₂ = −(X₃ + 10X₄); Y₃ = −(X₅ + 10X₆)
Multiplier / division: Y₁ = X₁ · X₂; Y₂ = −(X₃ + X₄); Y₃ = −X₅/2; Y₄ = X₇/X₆ (X₆ < 0)
Squaring and square root: Y₁ = X₁²; Y₂ = −√X₂ (X₂ > 0)

6. Technical Specifications

Basic Unit

Parameter	Value
Width (19” standard housing)	445 mm
Width (19” plug-in unit)	483 mm
Height (19” standard housing)	234 mm
Height (19” plug-in unit)	220 mm
Depth	485 mm
Weight	approx. 12 kg
Supply voltage	220 V/50 Hz
Power consumption	approx. 100 VA
Reference voltage	±10 V
Stability (90 days)	0.1%

Summers

Parameter	Value
Linear range	±10.5 V
Output current	5 mA
Bandwidth (−3 dB full signal)	80 kHz typ.
Resistor accuracy	0.1%
Overload recovery	20 µs

Integrator

Parameter	Value
Capacitors	1 µF, 0.1 µF, 0.01 µF
Capacitor accuracy	0.1%
Drift accuracy of IC mode (1 µF)	1 mV
Mode switching time	0.5 ms typ.

Potentiometer

Parameter	Value
Type	10-turn, wire-wound
Resistance	10 kΩ
Resolution	0.02%

Limiters

Parameter	Value
Slope after limit	20 mV/V
Adjusting range	±11 V

Multiplier

Parameter	Value
Static error	0.5% FS
Band width (−3 dB), x input	500 kHz
y → 10 V—set wt	500 kHz
Output current	5 mA

Variable Function Generators

Parameter	Value
Input spanning voltage	±10 V
Range of output voltage	±10 V
Output current	5 mA
Max. slope	9 V/s
Bandwidth (−1 dB, full signal)	8 kHz
Location of break points (FG 1)	±1 V, ±2 V, ±3 V, ±5 V, ±7 V, ±9 V
Location of break points (FG 2)	±1 V, ±2 V, ±4 V, ±6 V, ±8 V

Comparators

Parameter	Value
Switching time	20 µs
Sensitivity	10 mV

Logic Components

Parameter	Value
Type	TTL
Fan out	10
Outputs Monoflops, timer, counters	true
Flipflops, gates	true, false
Tolerance of timer frequency	±2%

All components are protected at their outputs against shortage and back-voltage. The specifications given above are referred to 25°C ambient temperature and a 10-minute warm-up. The specifications are subject to change without notice.

Published by: Dornier System GmbH, Postfach 1360, 7990 Friedrichshafen. Tel. 07545/81 – Telex 0734359. Document number: VC 77091000.