KEKB Accelerator Control System
T. Katoh and KEKB Controls Group, KEK, Tsukuba, Japan

Abstract
The KEKB accelerators are composed of High EnergyRing(HER) which stores 8 GeV electrons and Low
Energy Ring(LER) which stores 3.5 GeV. positrons.
The accelerators are installed in the 3 km circumference
tunnel where former TRISTAN Main Ring was. All themagnets, RF cavities and vacuum chambers weredismantled and carried away from the tunnel.
Design of the control system started in 1993[1]following the standard model, composed of presentation
layer, equipment control layer, and device interfacelayer.
After discussions, the EPICS(ExperimentalPhysics and Industrial Control System) was chosen as
the control software toolkit for KEKB accelerator
control system[2]. The operator’s interface layer iscomposed of a server workstation with 2 CPUs and 20
GB RAID disks. X-terminals are used as operators’
consoles and printers are connected to the server. The
equipment control layer is composed of 93 Input Output
Controllers(IOCs) with VME board using Power PC 750
CPU. These IOCs are used to extend field buses such as
CAMAC Serial Highway, GPIB, ARCNET, Modbus+and RS-232C. In the device interface layer, there are
CAMAC modules, GPIB devices, Power Supplies, PLCsand measuring instruments connected to RS-232C.
PCs are used as X-terminals and for generating video
signals and voices. Network stations made by IBM areused as inexpensive X-terminals at the local control
rooms, Macintoshes and small PCs are also used as Xterminals with multiple screens. Large 18-inch TFT
LCDs with resolution of 1280 x 1024 pixels are used as
display screens. The combination of a PC and LCD
screens enable us to have a very compact console
operated by a keyboard and a mouse.

1 SYSTEM HARDWARE
ARCHITECTURE
The KEKB control computer system is based on the“Standard Model” using EPICS toolkit. The model
consists of three layers: presentation layer, equipment
control layer, and device interface layer. System
configuration is shown in Fig. 1.

1.1 Presentation Layer
The highest level, presentation layer consists of aserver workstation, X-terminals, and peripheral devices.
On the server, ORACLE database system runs under HPUX operating system. X-terminals are used as standard

man-machine interface equipment. There are severalkinds of X-terminals corresponding to the purposes.
Standard X-terminals are used for developing software.
IBM Network Stations are used as terminals in the local
control rooms because they are very simple and have nodisk and fan. The software for the Network Station isdownloaded from the server workstation through thenetwork. Pcs and Macintoshes are used as intelligent
terminals. And they can have multiple screens for
operators by using multi-screen video interface board or
additional video board. It is very convenient for
operators to have multiple screens with only one set ofkeyboard and mouse.

1.2 Equipment Control Layer
This layer includes VME-bus based computers: Input
Output Controllers(IOCs).
A VME subrack withmodular plug-in power supply unit and plug-in fan unit
is used for each IOC in order to get good maintainability.
Ninety-three CPU modules with Power PC 750 orMC68060 are implemented in the IOCs. Each IOC has
an Reliability-Availability-Serviceability(RAS) board
which monitors power supply voltages of the VME
subrack and generates alarm messages when the voltage
becomes unusual.
The RAS board also accepts
commands from outside through an RS-232C port andresponds to various commands. One of the commands issystem reset. The system command is very useful for us
because we can reset the VME-bus and re-boot thesystem remotely. The IOCs are used mainly for driving
field buses such as CAMAC serial highway, ARCNET,GPIB, MXI-bus, Modbus+ and RS-232C. CAMAC
serial highway is used for RF and vacuum controls.
ARCNET is used for controlling magnet power supplies.
A plug-in module with embedded CPU was developed as
the power supply controller module that is plugged-in tothe magnet power supply itself. On each ARCNET line,
up to 20 poser supplies are connected. An example ofconnection of power supplies is shown in Fig. 2. GPIBs
are used to communicate with measuring instruments
such as digital voltmeters. MXI-bus is for connecting
VXI mainframes with the VME-bus. Modbus+ is used
for communicating with PLCs. RS-232C is used as thegeneral-purpose communication method with various
equipment such as mass analysers of the vacuum system,
sextupole magnet movers, and PLCs.

Colour
PostScript
Printer

PostScript
Printer

Ethernet
HubX-Terminals

FDDI-Ethernet Bridge

FDDI-Ethernet BridgeFDDI Concentrator

Server
FDDI Switch

Workstation

Central Control Room
26
Local Control Rooms
And Central
Terminal Room
FDDI-Ethernet BridgeTerminalServerEthernet
HubX-Terminal
VME Computer(IOC)CPU Module

Power Supply Module

RAS Module

GPIB

CAMAC Serial Highway Driver
ARCNET driverFig. 1. System Configuration of the KEKB Accelerator Control System

1.3 Device Interface Layer
This layer consists of various kinds of interface
modules and equipment based on the field buses
mentioned above. We have many kinds of CAMAC
modules for digital input/output, analog input/output,
andpulse output. VXI modules for FFT analysis and signal
multiplexing for beam position monitors are put in theVXI main frames and connected through MXI-bus.
Magnet power supplies are controlled by ARCNET
power supply controller modules[3] but monitored bydigital voltmeters using GPIB. PLCs are used forcontrolling devices and monitoring interlock status ofmagnets. They are connected to the IOC via Modbus+
or RS-232C.

1.4 Network System
Network system lies between the presentation layer
and the equipment control layer. It was the mostimportant point to get the most suitable network during
the design phase of the KEKB accelerator control system.
The circumference of the accelerator is about 3 km andit takes more than 10 micro-seconds to circulate a signal.
To avoid wasting time, we decided to use a switched
FDDI network as the back-bone. In the central control
building, an FDDI switch(GigaSwitch by former DEC)
was installed and 26 optical fibre links are extended
from there to local control buildings. At each local
control building, an FDDI–Ethernet bridge is installed toextend an Ethernet segment. Each IOC is connected tothe bridge and the console terminal port and the terminalport of the RAS board are connected to the terminal
server. In the central control room, there are several
Ethernet segments in order to separate network traffics.
One is for peripheral devices such as printers, DAT
back-up, the other is for X-terminals.

2 SOFTWARE ARCHITECTURE
EPICS software toolkit is used as softwareenvironment. In the EPICS system, each signal from theaccelerator equipment is read or written through standard
method called “Channel Access(CA)” provided byEPICS. There are three modes of the channel access; get,put and monitor.

2.1 Presentation Layer
The operating system for the server workstation is HPUX Version 10.2. For the presentation layer, Motifbased EDM(MEDM) is used to create graphical screensand display accelerator data using EPICS channel access.
Data gathered by the equipment layer are archived by
the software called “archiver“ on the server workstation.
All the accelerator information are stored in the databaseon the server workstation using Oracle 7 relational

database system.
The database contains machineparameters, interface information such as cabling,terminal numbers, interface module address, and so on.
EPICS record database is generated from the databaseautomatically. Therefore, after any change of thedatabase, one can easily generate the revised edition of
the record database.
Orbit correction is done by using SAD server
workstation that simulates the orbits of the two rings.
An interpretive language PYTHON is also supported inorder to make it easy to write application programmes.

2.2 Equipment Control Layer
The software on the IOCs runs on the real-time
operating system VxWorks and is cross-developed on
the server workstation using Tornado cross-development
system. It is down-loaded through the network. EPICSchannel access record database is also down-loaded.
Control programmes can be coded by using “sequencer”
and channel access. EPICS core programmes monitors
data whether the data is within certain limits or exceed
the boundary values. If the data value exceed the limits,
it generates alarm signals and the operator can know thefact on the MEDM screens.

2.3 Device Interface Layer
On this layer, all the intelligence is embedded in thecontrollers or equipment themselves. In the power
supply interface controller module, software forcontrolling magnet power supply is implemented. The
software contains direct current set up procedure andfunction generation scheme.

3 PCS IN THE SYSTEM
There are a little number of PCs in the KEKB
accelerator control system. They are divided into twocategories. The first is X-terminals, the second is for
specific applications such as generating sounds or video
signals.

3.1 X-terminals
PCs are used as the X-terminals by using X-Windowemulation software. A PC can generate multiple display
screens with high resolution by using multiple screen
display controller. A multiple screen display controller
named “Evolution 4” is installed in a small PC in orderto generate up to four SXGA(1280 x 1024) screens.
Macintosh personal computers are also used as Xterminals with multiple screens by putting multiple
video cards into the Mac. By using these PCs or Macs,
operator can see larger area than usual with only a set ofa keyboard and a mouse. Especially by using the latest
TFT displays, the operator’s console becomes so thinand light that the configuration can be easily changed.

3.2 Specific use of PCs

REFERENCES

PCs are also used because of its variety of hardware
and application software available.
The above
mentioned multi-screen display controller board is used
in a PC in order to generate multiple VGA screens which
can easily converted to NTSC video signals. We cangenerate up to four video signals by only one PC. A
Macintosh is used to generate alarm message foroperators[4].

SYNC[1] T. Katoh, et al., “DESIGN OF THE KEKBACCELERATORCONTROLSYSTEM”,
ICALEPCS’95, Chicago, Nov. 1995
[2] T. Katoh, et al., “PRESENT STATUS OF THE
KEKB CONTROL SYSTEM”, Proc. ICALEPCS’97,Beijing, Nov. 1997, pp. 15-18.
[3] A. Akiyama, et al., “KEKB POWER SUPPLYINTERFACE CONTROLLER MODULE”, Proc.
ICALEPCS’97, Beijing, Nov. 1997, pp. 243-246.
[4] N. Yamamoto, “VOICE ALERT SYSTEM USINGPC”, PCaPAC’99, Tsukuba, Jan. 1999

Steering
MagnetIOC
VME-VME
Ethernet

Power
SupplyARCNET~100mFig. 2 Configuration of the Steering Magnet Power Supplies