CAMAC Crate Research Articles

An Enhanced 8086-Based CAMAC Crate Controller

An enhanced CAMAC crate controller (ECC) has been developed for data handling for Fermilab experiment E-704. The module also is currently used in an experiment to make a precise measurement of the weak vector coupling constant. The ECC incorporates hardware to do block transfers (DMA) of CAMAC modules within the crate at several times effective CAMAC rates, or it may be programmed to do individual CAMAC transfers. If desired, data may be rippled out an ECL port to fast ECL devices, or may be written in RAM for processing within the controller itself. The EEC is implemented with the CAMAC Request/Grant protocol for use with an A-2 crate controller, allowing the ECC to be used either as an auxiliary controller or crate controller. Trigger logic in the controller allows the device to respond to any of three triggers by initiating a DMA, or dedicated crates may be daisychained, one crate providing a trigger to the next at the conclusion of each DMA. The device is built as much as possible in High Performance CMOS logic using surface mount techniques, on two 8-layer printed circuit cards.

A VME/VMX - CAMAC Interface and Crate Controller

A VME/VMX bus interface has been designed and built to interface a VME-based data acquisition system to CAMAC. The interface communicates via a differential bus with a companion unit that functions as a CAMAC crate controller. The interface maps both VMiE and VMX address cycles into appropriate CAMAC cycles. Special diagnostic features have been incorporated in the design to allow quick fault detection and location.

CAMAC Data Scanner with LRS4299 DATABUS Interface

A CAMAC data scanner was designed and manufactured. The scanner is in conformance with LeCroy's 4290 series DATABUS interface. The scanner supports CAMAC single action and block transfer mode with zero suppress capability. The S2 timing of CAMAC cycle may be skipped to squeeze data acquisition cycle. The scanners are located at front-end CAMAC crates in the FASTBUS based TOPAZ data acquisition system.

New High-Performance Computer Interfaces to CAMAC

Data acquisition and control systems have often included the need for high throughput between the front-end hardware and the host computer. This is particularly true in the aerospace/defense and experimental physics fields. With the advent of more sophisticated I/O hardware and faster host computers with larger memories, the need for higher performance real-time computer interfaces has increased dramatically. A family of CAMAC-based interface products has been developed that supports high data throughput while providing the flexibility to meet the particular application. These new products fall into three basic categories: enhancements to the CAMAC Serial Highway, new CAMAC crate controllers, and software drivers. The Serial Highway enhancements provide at least a five-fold improvement in effective throughput and rival the Parallel Branch Highway in that regard. A new crate controller with a ribbon-cable bus interface uses balanced-line transmission and supports a bus length to 500 feet. List processing is provided as a hardware option for the Serial Highway Driver and is supported by a list sequencer module, an auxiliary crate controller, as well as software device drivers. This paper describes these new products, details their performance, and recommends trade-offs for their application. Benchmark comparisons indicate the extremely high data throughput that has been obtained. With certain configurations, Serial Highway throughput approaching three megabytes per second can be achieved.

An Intelligent VME-Based CAMAC Crate Controller

A VME-resident Camac crate controller is described which maps all Camac functions into the address space of a 68000 microprocessor. The controller also contains a VME bus requester, thus allowing it to contribute Camac data, completely formatted, to a global event buffer.

Data Acquisition and Processing System for the HT-6M Tokamak Fusion Experiment

This paper describes a high-speed data acquisition and processing system which has been successfully operated on the HT-6M tokamak fusion experimental device. The system collects, archives and analyzes up to 512 kilobytes of data from each shot of the experiment. A shot lasts 50-150 milliseconds and occurs every 5-10 minutes. The system consists of two PDP-11/24 computer systems. One PDP-11/24 is used for real-time data taking and on-line data analysis. It is based upon five CAMAC crates organized into a parallel branch. Another PDP-11/24 is used for off-line data processing. Both data acquisition software RSX-DAS and data processing software RSX-DAP have modular, multi-tasking and concurrent processing features.

Final design of the control and auxiliary systems for the Balcones 60 MJ homopolar pulse power supply

The Center for Electromechanics at The University of Texas at Austin (CEM-UT) has completed the final design of a 60 megajoule (MJ) laboratory pulsed-power facility. Six identical 10-MJ homopolar generators are utilized in various series and/or parallel configurations to provide maximum output current and voltage ratings ranging from 1.5 MA at 660 V DC to 9.0 MA at 110 V DC. An overview of the guidelines and constraints governing the final design of this versatile system are presented. Topics include the homopolar generator terminal voltage matching via rotor speed and magnetic field control, control and hardware features, power supply configurations and output terminal ratings, failsafe fault protection, computer automated measurement and control (CAMAC) data recording system, radio frequency and electromagnetic interference (RFI/EMI) shielding considerations, signal processing, as well as the mechanical and electrical subsystems required for generator operation and protection.

Equipment for digital recording of transient signals

The instrumentation for digital recording of transient signals was built and incorporated into a system for pulse radiolysis experiments. A single analog signal which is displayed on the screen of the oscilloscope is captured by a TV-camera in the measuring set up. The camera is connected to a Camac crate which is directly linked to a microcomputer. The analog signal can be digitized and memorized in 128×256 matrix points.

An Ultrahigh Speed CAMAC Interface for a Large Flight Simulator System

The real-time simulation subsystem (RTSS) at the NASA Langley Research Center in Hampton, VA, consists of several CDC CYBER computers and over 20 flight simulation sites. This simulation network is used by the Langley Center to advance the state of aeronautics and to improve air safety. The current simulator interface system at NASA-Langley was installed in 1968 and uses centrally located analog and discrete conversion equipment. Of the alternatives studied by NASA for a replacement RTSS, only the network and input/output (I/O) system conforming to the international computer automated measurement and control (CAMAC) standards meets their requirements. The CAMAC serial highway provides a distributed I/O system with an extremely high data throughput approaching 24 000 000 information bits/per second. Fiber-optic links transmit the data over paths to 1 km. For multisite simulations, a computer-controlled electronic switch configures site highways in any combination. The CAMAC system uses analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and synchro converters with 16 bits of resolution to give the needed system performance. The time to acquire data from 80 16-bit ADCs and 960 discrete inputs and transfer them to the CYBER central memory is less than 320 ?s. Similarly, the time from CYBER central memory to the setting of 256 16-bit DACs and 960 discrete outputs is less than 650 ?s.

TFTR CAMAC data-acquisition system

Diagnostic data acquisition on Princeton’s tokamak fusion test reactor (TFTR) is accomplished via CAMAC (computer automated measurement and control system). This paper describes the capabilities of this instrumentation technique as applied to TFTR diagnostics and presents the family of CAMAC modules and equipment necessary for TFTR data acquisition and process control. These modules provide system configurations that range from meeting the basic requirements of digital and analog input/output to the requirements of transient digitizers, scalars, histogramming memory controller (each with add-on memory storage), timing and sequencing and timed gate units, function generators, and microprocessor interface units. The applications and guidelines that have evolved from our experience with TFTR CAMAC are presented.

Controls and data acquisition for the NRL modified betatron accelerator

A CAMAC based data acquisition and control system (DACS) has been developed for the NRL modified betatron accelerator. The design goal of the MBA is to accelerate single-shot multi-kA currents of electrons to 50 MeV. The DACS must perform three general tasks: (1) the control and shot sequencing of the accelerator, (2) the data acquisition of MBA shot data and (3) the archiving of the shot conditions, shot digitizer data, and oscilloscope data. A VAX 11 750 controlled system crate contains a serial highway driver that communicates with CAMAC crates in three remote locations via fiberoptic links. The DACS utilizes sensing and feedback to control capacitor banks, high vacuum pumping systems, high speed digitizers and the precision infector accelerator during shot sequencing. A control program written at NRL invokes CAMAC functions to perform shot sequencing, provide data acquisition, and archiving. The computer actuates switches that control equipment subsystems by operating relay logic and interlocking. Thus, the computer control functions in parallel with manual controls. The DACS logs the conditions before and after MBA shots. It also archives data acquired form the buffer memories of transient digitizers and from a PDP 11 23 controlled vidicon camera that digitizes oscilloscope photographs.

Final report on the FMIT control system

The computer control system for the Fusion Materials Irradiation Test Facility (FMIT) prototype accelerator was designed using distributed intelligence driven by a distributed database. The system consists of two minicomputers in the central control room and four microcomputers residing in CAMAC crates located near appropriate subsystems of the accelerator. The system uses single vendor hardware as much as practical in an attempt to minimize the maintenance problems. Local control consoles are an integral part of each node computer to provide subsystem checkout. The main console is located in the central control room and permits one-point operation of the complete control system. Automatic surveillance is provided for each data channel by the node computer with out-of-bounds alarms sent to the main console. Report by exception is used for data logging. This control system has been operational for two years. The computers are too heavily loaded and the operator response is slower than desired. A system upgrade to a faster local-area network has been undertaken and is scheduled to be operational by conference time.

Experience with the CES Starburst

Applications of the CES 2180 auxiliary CAMAC crate controller as a data pre-processor are described. They include track analysis in a wire chamber polarimeter to produce a smart trigger, and NMR singnal averaging for polarization measurements in deuterated targets. Methods of generating and down-line loading stand-alone FORTRAN programs for various host computers will also be described.

CAMAC crate controller on a FASTBUS cable segment

A CAMAC crate controller that can be attached to a FASTBUS cable segment has been designed to incorporate CAMAC systems into a FASTBUS environment. The controller meets the multiple controller specification of CAMAC. The block transfer modes are enhanced with functional shares with a FASTBUS master activity. The controllers are installed in the TOPAZ data acquisition system for the TRISTAN high energy electron-positron collider at KEK, Japan.

New general purpose interfacing modules for an accelerator control system

Two types of intelligent interfacing modules, CIM and DIM, for controlling many instruments have been designed. These modules can be used as an interfacing system which connects a CAMAC crate or a host computer with various controlled instruments. A CIM/DIM system which consists of a CIM and DIMs can communicate with 256 input and output ports of DIMs directly. Furthermore, it has a function as local controller for a group of instruments and can include 256 kinds of macroprograms for sequential control, data logging, etc.

A CAMAC based ultrasonic data acquisition workstation

Computer Automated Measurement and Control (CAMAC) is an instrumentation and interface standard that provides both hardware and software flexibility. Using standard CAMAC modules and a few custom designed routing and clock circuits we have developed a computer‐controlled system for general purpose ultrasonic scanning and data acquisition. The CAMAC system provides a relatively easy way of interfacing to the motor controllers and a transient recorder for complete computer control. The main advantage is that the interface software can be written in a high‐level language such as FORTRAN to send commands to individual modules in the system to move motors or to activate a transient or to readout the transient recorder data. The system has the capability of performing sequences of commands repeatedly so processes like signal averaging can be easily implemented. New, custom applications can easily be accommodated by changing modules and writing new interface routines in FORTRAN. For example, we have modified the basic system by replacing the transient recorder with a time‐to‐digital converter and we now have the capability to record time‐of‐flight ultrasonic data. Another example is the ease with which new scanning devices can be added to the system. The stepper‐motor controllers can be reprogrammed to accommodate the characteristics of the new device, again using a high‐level language such as FORTRAN.

CAMAC and LAN's

We are implementing an Ethernet interface for our intelligent CAMAC crate controller, CANDI 2, to connect it to the Ethernet Network which will tie together all of the Frascati National Laboratories computing facilities. We feel that Local Area Networks can add a lot of power and flexibility to a multicrate CAMAC installation.

CANDI2, a CAMAC microcomputer system for a physics laboratory

CANDI2 is an intelligent CAMAC Crate Controller which implements high resolution color graphics and is intended to be easy to use in a laboratory environment for both data acquisition and process control.

The LEGS Data Acquisition Facility

The data acquisition facility for the LEGS medium energy photonuclear beam line is composed of an auxiliary crate controller (ACC) acting as a front-end processor, loosely coupled to a time-sharing host computer based on a UNIX-like enviromnent. The ACC services all real-time demands in the CAMAC crate: it responds to LAMs generated by data acquisition modules, to keyboard commands, and it refreshes the graphics display at frequent intervals. The host processor is needed only for printing histograms and recording event buffers on magnetic tape. The host also provides the environment for software development. The CAMAC crate is interfaced by a VERSAbus CAMAC branch driver.

A Programmable Delay Unit Incorporating a Semi-Custom Integrated Circuit

The synchronization of SLC accelerator control and monitoring functions is realized by a CAMAC module, the PDU II (Programmable Delay Unit II, SLAC 253-002), which includes a semi-custom gate array integrated circuit. The PDU II distributes 16 channels of independently programmable delayed pulses to other modules within the same CAMAC crate. The delays are programmable in increments of 8.4 ns. Functional descriptions of both the module and the semi-custom integrated circuit used to generate the output pulses are given.