LSI-11 Microcomputer Research Articles

Data acquisition and monitoring system for the UHE gamma ray experiment at Kolar Gold Fields

A computerised on-line data acquisition system has been implemented to acquire data and monitor all the detectors in an extensive air shower experiment at Kolar Gold Fields, India, designed to search for point sources of Ultra High Energy gamma rays. It is based on the LSI-11 microcomputer, which has a powerful instruction set and a daisy chained vectored interrupt facility. Two personal computers are linked with LSI-11 through a 16-bit communication bus, to transfer data for a quick analysis. While the system performs this function in the background, it can be interrupted, at different priority levels, by several foreground functions, such as event data acquisition, detector monitoring, etc. The hardware and software features of the data acquisition system are described in detail.

A computer system for imaging and spectroscopy in analytical electron microscopy

The modern analytical transmission electron microscope gives signals from both elastically and inellastically scattered electrons at rates up to a few magabytes per second. A flexible multiasking system is needed to effectively integrate the information from a microscope with multiple detectors while synchronously controlling selected optical parameters of the instrument. We describe a system based on a Digital Equipment LSI-11 microcomputer equipped with a frame buffer and show how it has been used to develop new experimental capabilities such as time-resolved spectroscopy and multi-spectroscopy elemental mapping.

A robotic sample changer for a radiochemistry laboratory

A Microbot Alpha robot has been interfaced to a Nuclear Data Model 680 multichannel analyzer (MCA) and computer to allow unattended accumulation and storage of gamma-ray spectra. Software was written in DEC RT-11 system language to control the robot, MCA and dual floppy disk system from a DEC LSI-11 microcomputer. Typically, 8 spectra are accomulated for 3 hours each, providing 24 hours of unattended operation for one detector or 12 hours for two detectors. The system has proven to be highly reliable and has eliminated the need for operator intervention after working hours.

CSM: A Distributed Programming Language

This paper presents an overview of a distributed programming language called Communicating Sequential Modules or CSM, intended to support distributed computing. Developed from Modula-2 and CSP, CSM has been implemented on the ZCZ distributed microcomputer system consisting of several LSI-11 microcomputers. Its implementation is also described.

DMODULA: A distributed programming language

This paper presents an overview of a distributed programming language called DMODULA, which is intended for the programming in a distributed environment. DMODULA develops module concepts of its ancestor, MODULA-2, and provides features of generic and remote procedure calls. DMODULA has been implemented on the ZOZ system, a distributed microcomputer system consisting of several LSI-11 microcomputers, which was designed and implemented at Nanjing University in 1982.

Linking 8 and 16 bit microcomputers using the ieee 488 interface bus

The IEEE 488 bus is fast becoming the data communications standard in instrumentation industries. A system developed at Cranfield Institute of Technology allows a DEC LSI-11, a Texas Instruments TMS 9900 based microcomputer and two KIM-1 hobbycomputers to be linked in a mini-network mode. This system is the subject of the paper. To detect possible data transmission errors a number of methods are considered and the checksum method is implemented. In the LSI-11 microcomputer data transactions for the two protocols, software polling and interrupt, are demonstrated. The hardware used to construct the interfaces is fully detailed and the logic of the software is described.

ZCZOS

ZCZOS

Remote Ground-Based Observations Of Terrestrial Airglow Emissions And Thermospheric Dynamics At Calgary, Alberta, Canada

The article discusses the automated optical observatory at Calgary, Alberta, Canada at which three sophisticated optical instruments are operated unattended via telecommunications between the laboratory and observatory computers. These instruments are a single-etalon, 15-cm Fabry-Perot interferometer with six filter channels, a tilting filter with four filter channels, and a 1-m Ebert-Fastie spectrophotometer. The instrumental control computer is a LSI-11 microcomputer packaged with dual floppy disk drives. The observatory has been operating with good results since September 1981.

Packet Switching in the MICRONET Network Computer

Packet switching is a communication technology which has been used extensively in geographically distributed computer networks. It is also applicable to the communication subnetworks of compact multimicrocomputers known as network computers. This paper describes the use of the language Concurrent Pascal to build a packet-switching subsystem for the MICRONET network of DEC LSI-11 microcomputers. Examples of actual Concurrent Pascal source code taken from the system demonstrate the usefulness of high-level languages with abstract data types for complex communication software.

On-line microcomputer system for analysis of precordial maps

An inexpensive system was developed for automated on-line analysis of ST segment heights, Q, R, and S heights and areas under these peaks, using an LSI-11 microcomputer. System accuracy was evaluated using a computer graphics technique which enabled magnification and labelling of the computed peaks on 60 maps from 17 patients. To compare the computer with hand analysis, the sigma ST (.06 seconds from S nadir) for 20 maps was calculated by three blinded observers. Correct computer evaluation occurred in all but five of 2058 leads. The mean observer sigma ST was 3.2 millivolts (range 0.77-7.5 mv). Mean inter-observer SD was +/-0.21 mv. The mean computer sigma ST was 3.5 mv (range 0.82-9.3 mv). The spread between computer and observer was +/-0.45 mv. Discrepancies between computer and observer were due to cumulative imprecision in observer measurements. This system has proven to be a practical and economic solution to handling the large volume of data accumulated with serial precordial mapping. It is considerably more precise than conventional hand analysis. Additionally, the system's versatility makes it ideally suited to many clinical and research functions.

OMSI Pascal-1 for ROM Applications

A microcomputer-based system which executes code in read-only memory (ROM) and is written in the high-level programming language Pascal was developed for the Nuclear Test Program at the Lawrence Livermore National Laboratory. This system is a part of a network of LSI-11 microcomputers which control, monitor, and acquire data from digital measurement devices. The Pascal language itself is a powerful and flexible tool for software engineers in the development of well-structured software that can be easily maintained. This paper describes a technique for developing code in the OMSI Pascal-1 language Which will execute successfully in ROM.

An implementation and empirical evaluation of the tasking facilities in ADA

An implementation of Ada's tasking facilities, on the LSI-11 microcomputer, is described.The performance and the size of the kernel are compared with those of another language having the same basic characteristics, but with a synchronization mechanism based on shared data.The execution of typical test examples shows that the time spent in the two kernels is more or less the same.

Control System for the Stony Brook Superconducting Heavy-Ion Linac

The control system for the Stony Brook Superconducting Heavy-Ion LINAC is described. Familiar response characteristics and convenient operation have been given high priority in the design. A star network of 9 LSI-11 microcomputers forms the basis of the system which in addition comprises a PDP 11/34 minicomputer, one 6502 microprocessor-based RF controller for each of 43 resonators, and several I/O devices such as graphics display and reassignable control knobs.

Magnetotelluric studies at Cerro Prieto

Ten magnetotelluric soundings were made near the production zone at Cerro Prieto, bringing to 17 the number of stations occupied in and around the geothermal field during 1978 and 1979. Results from the first seven soundings were reported elsewhere (Gamble et al., 1980). Data were analyzed in the field using a DEC LSI-11 microcomputer installed in a recording truck. The new soundings provide new information on the geometry of the geothermal system. We find evidence for a narrow resistive zone plunging southeastward, at a shallow angle, from a concealed apex a few hundred meters north of the power plant. This zone comes within about 500 m of the surface and can be traced roughly 5 km to the south. This zone correlates very well with a region of hydrothermal metamorphism, which has been identified by means of detailed studies of cores and cuttings from wells. The three dimensionality of this feature, combined with the influence of the large resistivity contrast between valley sediments and Cucapa Range granites 10 km to the west, makes a rigorous quantitative interpretation impractical. Although such an interpretation awaits further advancements in the techniques of calculating electromagnetic scattering by complex geological structures, the general picture seems clear. A comparison of the subsurface resistivity model with the position of the production zone and with subsurface geology suggests that the heat source lies at depth, roughly 4 km SSE of the present power plant. North of the power plant a two-dimensional interpretation of the magnetotelluric data is possible. A good fit between observed and calculated parameters is obtained for a subsurface model that is consistent with the model derived from dipole - dipole de resistivity measurements.

Signal averager interface between a Biomation 6500 transient recorder and an LSI-11 microcomputer

This paper describes the design and implementation of a versatile and compact signal averager interface between a Biomation 6500 transient recorder and an LSI-11 microcomputer. The design allows for fast signal averaging in excess of 1 kHz and is also easily software configurable and controllable. This permits the rapid recovery of high-speed waveforms at a minimum sampling time of 2 ns (500 MHz sampling rate). The interface has been incorporated into an LSI-11 system using the RT-11 V3B operating system and found to perform very satisfactorily.

Micros, A Distributed Operating System for Micronet, A Reconfigurable Network Computer

MICROS is the distributed operating system for the MICRONET network computer. MICRONET is a reconfigurable and extensible network of 16 loosely coupled LSI-11 microcomputer nodes, connected by packet-switching interfaces to pairs of high-speed shared communication buses. MICROS simultaneously supports many users, each running multicomputer parallel programs. MICROS is intended for control of network computers of thousands of nodes.

Application of Microcomputers to Automatic Weld Quality Control

The demand for increased productivity of welding operations has led to the expanded use of computer control to allow higher production rates while maintaining weld quality. The charateristics of the gas metal arc welding process and the relationship between welding parameters, the desired output of the welding process, and the automation of the process are discussed. A strategy for two-axis welding torch positioning and velocity control is developed based on preview control techniques. To evaluate the applicability of the proposed control method the motion of heat source along different welding paths is simulated on an analog computer with on-line control of process time constants by an LSI-11 microcomputer. The simulation results show that high quality seam tracking can be accomplished by controlling the torch motion using the proposed method. The method appears to be suitable for on-line control of welding processes.

A feedback system for steering and correcting the energy of the SLAC beam in the beam switchyard

This system provides closed loop feedback position and energy steering of the SLAC beam line ‘A’. The position monitoring and control mechanisms include four pairs of non-intercepting position monitors, four corresponding steering magnet pairs, and two non-intercepting charge monitors. The energy monitoring and control mechanism consists of a position monitor placed where the beam's horizontal displacement is proportional to its momentum, and a device for controlling the energy contribution to the beam of two of the accelerator klystrons. All of these are read and set by CAMAC modules accessible to an LSI-11 microcomputer which performs the feedback control.

Technical overview of the Renaissance Octobus system

With the recent availability of inexpensive micro-computers, a technique for effectively sharing the still costly peripherals is needed. This paper summarizes the OCTOBUS, a multi-processor microcomputer architecture and system designed to meet this requirement. The current implementation is based on DEC's LSI-11 microcomputer.

Microcomputer-based multiplexer for performing depth profiling with an Auger electron spectrometer

A microcomputer-based instrument for the automated profiling of samples with an Auger electron spectrometer and Ion Gun is described. The instrument records the changing heights of spectral peaks as it controls spectrometer scanning over predefined windows. Interactive front panel controls are used to set up a run and control profiling operations. The generated data is stored on a magnetic disk for later analysis and plotting. Implementation of the device using an LSI-11 microcomputer and interfacing hardware is detailed, along with the characteristics of the fortran iv driving software. An exploration of future capabilities and applications of the multiplexer is also given.