NBSIR 73-270 ^)

Field Service Test Model:

Computer-Controlled U System

Manual for Computer Subsystem

R. J. Carpenter

E lectronic Instrumentation

Measurement Engineering

Institute for Applied Technology

K. M. Gray

D. S. Grubb

L. J. Palombo

Measurements Automation

Information Processing Tectinology

Institute for Computer Sciences

and Technology

August 23. 1973

Instruction Manual

Prepared for Department of the Air Force HQ ^ USAF (AFTAC. TAP)

Patrick A. F. B., Florida 32925

NBSIR 73-270

FIELD SERVICE TEST MODEL:

COMPUTER-CONTROLLED U SYSTEM

MANUAL FOR COMPUTER SUBSYSTEM

R. J. Carpenter

E lectronic Instrumenta tion Measurement Engineering

Institute for Applied Technology

K. M. Gray

D. S. Grubb

L. J. Palombo

Measurements Automation

Information Processing Technology

Institute for Computer Sciences

and Technology

August 23, 1973

Instruction Manual

Prepared for Department of the Air Force

HQ ~ USAF (AFTAC/TAP)

Patrick A. F. B.. Florida 32925

/ w \

U. S. DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary

NATIOWAL BUREAU OF STANDARDS, Richard W. Roberts, Director

FIELD SERVICE TEST MODEL: COMPUTER-CONTROLLED U SYSTEM

MANUAL FOR COMPUTER SUBSYSTEM

R. J. Carpenter, K. M. Gray

D. S. Grubb and L. J. Palombo

1 . INTRODUCTION

The computer subsystem monitors the status of the receiver and

its output signal; performs the necessary programmed calculations on

the status and signal; manipulates the receiver's controls for

proper operation of the receiver; and records the phase of the output signal. The overall system is shown in figure 1 and the computer

subsystem is shown in figure 2.

The computer subsystem includes a minicomputer with a 16-bit

word size, 32K words of core memory, and processing power adequate

for the control of up to 15 receivers. It also includes input/

output logic for the use of several computer peripheral devices

and for input/output data for the receivers. The peripheral devices

include two teletypewriters, a high-speed paper tape reader, and

a magnetic tape unit. Interface logic is provided for a high-speed

paper tape punch.

Each receiver provides three analog inputs to the receiver:

Phase Difference, Amplitude, and Blanking Percentage. The first

two are from the receiver and the latter from the ADACS Interface

Certain commercial equipment and materials are identified in

this paper in order to adequately specify the components used. In no case does such identification imply recommendation or endorsement

by the National Bureau of Standards, nor does it imply that the

material or equipment identified is necessarily the best available

for the purpose.

1
Chassis. Each input is filtered to remove high frequency noise.

The inputs are then multiplexed and the multiplexer output used

with a sample and hold circuit as the input to a 12-bit analog-todigital converter. The digital outputs of the converter are input

data for the computer. The 15 receivers use 45 of the available 48

input channels.

Each receiver provides, via its ABACS unit, a 16-bit word of

digital data to the computer. The real-time clock provides 2 words

of time information and a wired connector plug is used to provide 1

word of information for the unit/detachment number. These words are

multiplexed to provide a stream of 16-bit words to the computer.

The 15 receivers (if that many are used), the 2 real-time clock words

and the unit/detachment word use 18 of the 22 available digital input channels.

The computer program generates a 16-bit digital output word to

send to each of the receivers via its ABACS unit. The 15 receivers

use 15 of the available 16 digital output channels.

Interrupts from the receiver's ABACS units are "daisy-chained"

to provide a single computer interrupt. The real-time clock

provides one interrupt for seconds and another for minutes. The

least significant bit from each cardioid unit is used with the

Common Alarm circuit of the computer subsystem to generate an interrupt when the status of one of the cardioid units changes. These

interrupts use 4 of the available 8 interrupts for the computer subsystem.

2
2 . CONFIGURATION

The computer subsystem requirements were specified, and the

MODCOMP III computer was selected. In the following descriptions

of the system the MODCOMP model number is given for each of the

features and attachments (see figure 2).

2.1 CENTRAL PROCESSING UNIT (CPU)

The CPU, a MODCOMP III, is a general-purpose, 16-bit digital

computer mounted in a 19-inch wide rack enclosure with the necessary

power supplies for use on 117 volt a.c. The CPU contains an

arithmetic unit, a read-only memory for the instruction controls, a

32K word core memory, 15 general registers, 8 priority interrupt

levels, an operator's console, and a built-in controller for a

teletype unit and a high speed paper tape reader.

Logic was added to provide hardware multiply and divide (model

number 3503) . The core memory uses 4 sections of 8K words (model

number 3608) for a total of 32K words, with byte parity (model

number 3606) for the detection of memory errors. A power-failsafe and automatic start feature (model number 3739) feature was

added to protect against power failures. "Direct Memory Processor"

for automatic block transfers (model number 3704) was provided.

2.2 PERIPHERAL DEVICES

Several peripheral devices are attached to the computer for

operator use. An ASR-35 console Teletypewriter (model number 4235)

is attached using the computer's built-in control logic. The ASR35 contains a keyboard, a page printer, a paper tape reader, and

a paper tape punch. The printer, reader and punch are relatively

3
slow devices. All of the devices use USASCII code.

An ASR-28 console typewriter is also attached to the computer.

It is similiar to the ASR-35 in its general features, but uses 5-bit

Baudot code. It is attached to the computer by an asynchronous

communications interface (model number 4810)

A high-speed paper tape reader (model number 4511) capable of

625 characters per second is attached to the computer using the computer' s built-in controller.

A magnetic tape unit (model number 5149) for 7 track, 25 inches

, per second, 556/800 bit-per-inch magnetic tape using 10.5-inch reels

: is attached to the computer using the peripheral controller interface (model number 4901) . The latter is designed to permit the

attachment of a high-speed paper tape punch and up to two other

input/output controllers.

2.3 RECEIVER INTERFACING

The analog and digital data to and from the receivers is interfaced with the computer via the Connector Panel and the I/O interface

subsystems. The Connector Panel provides a common point for the connection of the cables from the various receivers and the real-time

clock. Card plugging for the interface subsystems is shown in

figure 3.

The three analog input lines for each receiver are filtered to

remove high frequency noise and harmonics of the 60 hertz power.

Each filter unit (model number 1224) contains filters for 16 lines

and uses a cutoff frequency of 148 hertz. The analog lines are

multiplexed on the multiplexer gate cards (model number 1210) . The

4
output from the multiplexing is used with a sample and hold circuit

as the input to the analog-to-digital converter. The output of the

analog-to-digital converter is a 12-bit digital for the computer.

For more details on the 1200 interface subsystem, see the manufacturer's technical manual on the Analog Input Subsystem 1200.

The 16 digital bits from each receiver's ABACS unit to the

computer enter the interface subsystem logic via the Connector Panel.

From there the bits are sent to a digital input channel card (model

number 112A in the 1100 chassis), which provides the signal conditioning. The 16 digital bits and flag pulse to each receiver's

ABACS unit from the computer leave via the digital output channel

card (model number 1131 in the other 1100 chassis) , which drives

the lines through the Connector Panel to the ABACS units. The flag

pulses are generated by 1101 cards that have been modified to produce

10 microsecond pulses. Only one interrupt line is received from the

ABACS units, as the interrupts are "daisy-chained". This interrupt

enters via the Connector Panel to an I/O Interrupt Coupler card

(model number 1161). For more details, see the manufacturer's

technical manual on the I/O Interface Subsystem 1100.

3. REFERENCES

The manuals for the various units of the computer subsystem

contain detailed descriptions and diagrams. Programs supplied with

the computer are also described in the manuals on programming.

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FORM NBS-114A (1-71) U.S. DEPT. OF COMM. 1. PUBLICATION OK REPORT NO. BIBLIOGRAPHIC DATA NBSIR 73-270

SHEET

2. Gov't Accession

No.

3. Recipient's Accession No.

4. TITl.H AND S'J HTM LE FIELD SERVICE TEST MODEL: COMPUTER-CONTROLLED U SYSTEM

MAIWAL FOR COMPUTER SUBSYSTEM

5. Publication Date August 23, 1973

6. Performing Organization Code

O V v> J_

7. AUTHOR(s) R. J. Carpenter, K. M. Gray

D. §. Grubb and L. J. Palombo

8. Performing Organization

IMCoiK /j— Z/(J

9. PERFORMLN'G ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/ Work Unit No. 6505413

11. Contract/Grant No. AFTAC T/2301/U/NBS

12. Sponsoring Organization Name and Address

Department of the Air Force

HQ USAF (AFTAC /TAP)

Patrick A. F.B. , Florida 32925

13. 1 ype of Report & Period Covered

Instruction Manual

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a sigr-lficant bibliography or literature survey, mention it here.) This manual contains a description of the computer subsystem used to control t'he operation of the receivers in the U System. The diagrams show the connection of the

computer subsystem to the other units in the system, the arrangement of the components

within the computer subsystem, and the card locations in the I/O interface portion of

the computer subsystem.

17. KEY U'ORDS (Alphabetical order, separated by semicolons)

ADACS; computer-controlled receivers; U system

18. AVAILABILITY STATEMENT

UNLIMITED.

:X l"^-">i'. Ot- rfCI A!. 0!^-TRir-U !'ION. [)() NO T RELEASE

TO NTIS,

19. SECURITY CLASS

(THIS REPORT)

UNCL ASSIFIED

20. SECURITY CLAS-

(THIS i'AGE;

UNCLASSIFIED

21. NO. OF PAGES

22. Price

USCOMM-DC 6624J.P~I