JAERI-Conf 95-021

PB24
CONSTRUCTION OF A REMOTE CONTROLLED MONITORING SYS1EMWITH GPIB DEVICES AND EPICS
Takeshi YOSHIKAWA and Noboru YAMAMOTO+Electronic Control Systems Division, Hitachi Zosen Co., Osaka-shi, Osaka-fu, 554 Japan+National Laboratory for High Energy Physics (KEK), Tsukuba-shi, Ibaraki-ken, 305 Japan

Channel Access Clients(workstations, OPis)

Abstract
DisplayManagers

The Experimental Physics and Industrial
Control System (EPICS) has been used for theaccelerator control system in recent years.
EPICS has rich set of tools to create application
with Graphical User Interface (GUI). It reduces
the load of complex programming for GUI andshortens the application development period.
the remote
This paper will describe
temperature monitoring system using EPICS.

Archivers Sequencers
AlarmManagers

OtherClients'lt@~~~
Channel AccessDistributed
RunTime
Database

1. Introduction
Slow drift of a beam orbit in TRISTAN Mainring is observed during a long time operation. It
caused the degration of the performance of themachine.
beenOne reason for this slow drift hasthought as the temperatures of magnets in thering. Drift of temperature can affect the orbit ofthe thermal expansion ofbeam throughWe build aelectromagnets and its supports.
system to monitor the temperatures in theaccelerator tunnel to study correlation between
the temperature drift and the beam orbit drift.
Thermocouples are used as temperature
measurement device. Data collected bythermocouple controller are sent to a VME
computer through GPIB/LAN (local areanetwork) linker. User can control and monitor
this system by EPICS tools.
2. EPICSEPICS 1>·2> is a scalable, distributed processcontrol system that is built on a softwarecommunication bus called Channel Access.
UNIXincludes thearchitecture
EPICSlevel
highexecutingforworkstations
applications (including operator interfaces),and single board computers as front endcomputers, called Input Output Controllers orIOCs. The single board computers in VME crates
are used as IOC. Communication among thedistributed components is over TCP/IP sockets,
via ethernet or FDDI.

-t>-<:1-Hardware

Interfaces

Channel Access Servers(VME single board conputers, IOCs)

Figure 1. Functional subsystem layout ofEPICS. The only sequencer
runs on both OPI and IOC.
The EPICS architecture provides a wide range offunctionality, rapid application development
and modification, and extensibility at all levels
to meet the demands of experimental physics.
The hardware and software for each functional
subsystem were selected to meet these
theare:subsystems
The
requirements.
Distributed Database, the Display Manager, theAlarm Manager, the Archiver, the Sequencer,
and Channel Access (see Figure 1). These
functional subsystems greatly reduce the needfor programming. Sequential control is provided
through a sequential control language, allowing
the application developer to express state
diagrams easily. Data analysis of the archived
data is provided through an interactive tool. The
system is scalable from a single test station
with a low channel count to a large distributed
network with thousands of channels. All data ispassed through the channel access protocol. One
can extend the basic EPICS system in IOC bycreating new database record types, calling 'C'
subroutines from the database, extending the-315-

JAERI-Conf 95-021

driver support
VxWorks task.

andcreating

independent

Send the message to the specified user byan e-mail if there is no answer form IOC
to OPI or the data from the measurement
system for the temperature is same asprevious data including the time stamps.

3. Monitoring System
We built a monitoring system for thetemperature measurement with EPICS. The
reasons why we employed EPICS are:1) No need for programming except driver
support.
2) Easy modification for the monitoringsystem.
3) Easy addition for the measurement
channel.

Temperature

Monitor~ MONITOR I
IGPIB
LI0,0,5Commandstop.,., 40.,tostart~~e 3oa-~0.

El~ 20stop-150 -100 -50

0Time [sec.]

startthermocoupleg)

measuring system fortemperatureSCAN DISPLAY
Figure 3. System architecture.
tempO templ temp2

l29.4ll2s.4l~Figure

2.

Control panel. The display
panel for the current valueof the temperature comes out
if the DISPLAY button ispushed.

3-1. System functions
The functions of this monitoring system are:1) Device control
Transmit the GPIB command set on thecontrol panel created by
the display
manager to the measurement system forthe temperature (Figure 2 shows thecontrol panel).
2) Status/ Data Display
Display the current temperature and plot
its last 200 seconds' history.
3) Data Archiving/Retrieving
Record the temperature data measured by
the measurement system for thetemperature into the disk. And readout
and displays the recorded data.
4) Alarm Notification

3-2. System architectureThis system consists of workstation, VME
single board computer, GPIB/LAN linker,
computing data logger, sensor terminal, andthermocouples. Figure 3 shows the arrangementof these components.
The functions and names of each component
are:Workstation
HP 9000 workstation model 735/755 isused as an Operator Interface (OPI) inEPICS, and runs the UNIX operating
system and a number of EPICS tools suchas the archiver, the display manager andthe alarm manager.
VME single board computer
FORCE CPU40 is used as an Input OutputController (IOC) in EPICS, and runs theVxWorks real-time kernel and a numberof EPICS programs such as the distributed
database and the sequencer.
GPIB/LAN linker
SONY Tektronix ET488 exchanges the datafrom the data logger through GPIB tooutput to ethernet and performances aGPIB controller.

-316-JAERI-Conf 95-021

Computing data logger, sensor terminal,thermocouples
ADVANTEST TR2731, TR2741 andthermocouples compose a measurementsystem for the temperature.
NetworkThe network among the workstation, theVME crate and GPIB/LAN linker isethernet on which the transmission speed
is 10 Mbps.
3-3. Data acquisition
The process of data acqmsltlon is as follows.
1) The operator initiates the start commandfor data acquisition on the control panel,to process the database record.
2) The database record issues the GPIB
command which starts the sensor terminalor programming for the data logger.
3) The data logger starts the sensor terminal,
complying with the GPIB command fromthe database record.
4) The sensor terminal collects the data fromthe thermocouples which are in theaccelerator tunnel.
5) The temperature data collected by thesensor terminal are sent back to the IOC(database) via GPIB/LAN linker.
4. Conclusion
By using EPICS, there was no need of coding
except the driver support for the GPIB
controller, device support for the data logger
and sequential control.
added toAnother measurement point can be
the system just adding a new record to the EPICS
run-time database. User can easily modify theoperator interface (control) panel using EPICS
tools. Furthermore, by connecting the GPIB
controller to LAN directly, we can place theGPIB devices in many places.
Acknowledgments
We would like to thank Prof. R. Sugawara andProf. H. Fukuma for their encouragement andsupport during this work.
References
1) L.R. Dalesio, J.O. Hill, et al.: "Theexperimental physics and industrial
past,architecture:systemcontrolpresent, and future", Nucl. Instr. andMeth. A 352 (1994) 179.

-317-2)

M.R. Kraimer: EPICS(IOC)
Controller
Developer's Guide.

Input/Output
Application