Preliminary Design of the Control System for
SSRF and BTCF
Jijiu Zhao , X.S. Geng, F. Zhang, T.J. Shen*The Institute of High Energy Physics, Chinese Academy of Sciences
P.O.Box 918(10) Beijing 100039, P.R.China*Institute of Nuclear Research, Shanghai, China

Abstract
The Shanghai Synchrotron Radiation Facility (SSRF)
and the Beijing T-charm Factory (BTCF) are new highenergy physics projects in China.The control division ofIHEP undertook the feasibility research and conceptual
design of the control system in 1996. This paper presents
the conceptual design of the control system for both ofthe SSRF and BTCF.
The control system adopts a distributed architecture.
High performance workstations with graphic userinterface will be used as the console. A large number of
VME/VXI based microprocessors and Programmable
Logical Controllers (PLC) will be used as the front-ends
to take the control jobs for the accelerator equipment.
The high speed network and the field buses are
considered in the device control layer. The software tool
kits EPICS will be chosen to develop the controlsystems. In addition, some key technologies are also
discussed in the paper.
1 Introdution
In recent years, the two new projects in the field ofhigh energy physics were put forward by Chinesescientists. One is the construction of a new generationsynchrotron radiation facility in Shanghai (SSRF) which
includes the 100 MeV linac, transport line, 2.2 to 2.5
GeV booster and storage ring to serve the synchrotron
radiation experiments. The other is the Beijing T-charm
Factory (BTCF) , which is a new electron positron
collider with the 1.5 to 3 Gev beam energy which willreach its luminosity as high as 1×1033 cm-2sec-1 at 2.0
Gev.The BTCF will be the best facility in the world for
exploring T, Charm and charmonium physics. The R&Dof SSRF will start in the near future.
The control system must be capable of (1) operating allof above facilities as machines with separate missions
and controlling devices in central or local control rooms(2) controlling and monitoring all equipment of theaccelerators including various magnet power supplies,
RF cavities, vacuum units and different kinds ofinstruments for beam diagnostic systems. If something
goes wrong in those devices, a reaction must be made by
the system and an alarm report should be sent to theoperating console at once and (3) providing the methodsof accelerator commissioning and a friendly manmachine interface for operators.
Considering the above requirements,the control systemshould consist of the following parts:(1) The computer control system
The host and front-end computers
The network system
The man-machine interfaces
The database management system
The data logging and alarm report system
Applications(2) The timing system(3) The interlock system(4) The television and communication system
2 Design philosophy
In the 90's, the distributed processing system has been
widely adopted in the world, therefore the control system
will be a distributed control system based upon
microprocessors which are linked by high speed
networks. The subsystem control computers are loosely
coupled for the convenience of independent operation at
maintenance time. The standard and commercial hardware and software products should be applied in thesystem,and their cost-performance should be considered.
The mature technologies of accelerator control systems
in the world will be adopted.
The following points should be considered during thedesign stage: (1) Selection of computer systems
according to the different usage of the console computers, central server and front-end computers. (2)Selection of the computer operating system. A real-time
operating system should be chosen for the front-endcomputers. (3) Selection of high speed network to serveas data communication. (4) Selection of standard I/O
modules, (5) Applying commercial software. The selection of hardware and software is important fordeveloping and maintaining the control systems.
3 Distributed architecture
The control system is based on multi-level architecture of distributed processing system.[1] Logically thesystem is structured into three levels (as Fig1 shows),
which are the operator interface layer, the front-end layer
and the device controller layer.
The operator interface layer comprises operator
consoles and server processors providing, the high-level
program support, database support, shared files, network
management and general computing resources. Console
computers are a set of workstations and PCs which havea friendly graphic man-machine interface.
The front-end layer concentrates the control activities

of sets or assemblies of equipment or entire subprocesses. It consists of several local control stations,sotechnicians can adjust and maintain these subsystems atthe local control stations.

Figure 2. Software Structure of the Control System
as the control system development toolkits.
4. Key technology
4.1 Computers and operating system

Figure1. Structure of the Control System
The front-end layer provides distributed proce-ssing
power. A large number of microprocessors will be used
as front-end computers to take the control jobs for theaccelerator equipment and exchange the information
with the central server computer through the network.
The device controller layer provides interface to thehardware, either as separate modulers or as microprocessors incorporated in the equipment to becontrolled.[2] The Field buses will be used to connect theintelligent devices or some instruments exchanging data
between front-ends and the device controllers.
The network links connect the control computers andthe microprocessors serving data communication. Thisarchitecture has the advantage of localizing the hard realtime activities as near as possible to the equipment. It
also provides the possibility to reduce the amounts ofdata that are transferred to the upper layer.
The control system software architecture is divided
into the several parts as shown in Fig2.They are console
manager, datebase server , network communication andfront-end controls . In such a distributed structure,
database plays an essential role as the repository of all
information to which all parts of the control system refer.
A real-time multi-task scheduler in the network environment will be developed to manage application processes
running on different nodes.A numberof I/O driver
routines and application programs for accelerator control
should also be developed. EPICS will be chosen

The selection of the computers and its operating
system is important for system standardization.
The SUN, HP, or DEC, workstation with X-window,
OSF/motif can be chosen to be used as the console, andsome kinds of personal computer with windows,
windows NT can be chosen for some sub_system
controls. The central server computer and its operating
system should be some mini-computers such as HP or,
DEC Alpha computers. The UNIX operating system isrecommended for the first choice.
For the front-end computer, the VME/VXI single board
computers should be used for real-time control jobs with
the VxWorks (or with Tornado interface) real-time
operating system.The single-chip microcomputers could
be used as device controller within the equipment.
4.2 Network
The console and server computer will be connected tothe front-ends by a local area network link (LAN). As thebackbone of the network, Fast-Ethernet can provide
appropriately scaled access to the distributed equipment
locations. Individual connections to FECs will be madevia Ethernet. The TCP/IP network protocol has been
selected. It provides the network file system NFS,
network information service NIS, remote file sharing
RFS and remote procedure call RPC.
4.3 Front-ends
All of the real-time tasks will run on the front-ends
which have the capacity of parallel processing. Allcontrol and data acquisition transactions with themachine's equipment take place here. It translates astandard data representation in the control system to asuitable format for devices and device control modules.
The raw data from devices are stored in the local

database of the FECs. Only necessary data for the highlayer will be sent out so that the overhead of the networktransmission can be reduced.
The execution code running on front-end will bedeveloped by a development system with UNIX and theVxWorks operating system. The VME products with
MC680X0 or power PC microprocessor,VME/VXI bus
and variety of VME I/O modules might be chosen as
front-end units.The Programmable Logical Controller(PLC) will be used in the front-end layer to serve thedigital and slow controls. (See Figure3)

After system analysis, designing, modeling andsimulating stages, the system can be constructed. Thereis a set of software tools and applications, Experimental
Physics and Industrial Control System (EPICS), jointly
developed by ANL and LANLof United States. The
EPICS consists of OPI, IOC and CA.[4] With EPICS, thedevelopers of the control system can generate a
distribution database automatically, access I/O channels
on the UNIX workstations conveniently, and creategraphic man-machine interface easily. So it is better todevelop the control systems by EPICS. Recently, a new
application program interface CDEV of EPICS has beendeveloped by Jefferson Lab, We will consider to use it in
the two new projects.
5 Timing system

Figure 3. The Front-end and device comtroller
The field bus will be used for data communication
between devices in the field and high layer FECs[3] . The
following products can be chosen as a field bus:
CANbus, Profibus, or lonworks.

The timing system provides the synchronization of theaccelerators. For the SSRF, on the one hand, a slow
timing system generates a trigger sequence tosynchronize electron gun, klystron, modulator in Linac,and septums, kickers in the Booster and Storage Ring, on
the other hand, the fast timing signals generated by ECL
circuits synchronize beam bunches sent by the electron
gun with the bucket in the Booster or Storage Ring, sothat the bunch can be injected into the corresponding
buckets.
The trigger pulse generated from the RF frequencygenerator which is 500MHZ will be transmitted to theelectron gun as the base of the synchronous clock.
Trigger jitter should be less than 500ps.
6 Conclusion

4.4 Graphic man-machine interface
The console should have a friendly graphic manmachine interface which is easy to use. The console
manager software will be based on X-window,OSF/motif, Medm of EPICS, TCL/TK, Labview, andILOGview graphic packages. A graphic subroutine
library will be provided for application programmers todraw pictures on the console.
4.5 Database
A distributed relational database, such as Sybase, is an
important part of the control systems. With an Openclient and SQL server of Sybase, much useful data withtime stamps can be stored and analyzed. In recent years,
the object-oriented database has been used in the field ofaccelerator controls, so we will pay attention to thedevelopment of the OODB.
4.6 Software tool kits

The SSRF and BTCF are new generation ofsynchrotron radiation facility and collider so there will
be some special requests for the control system. Up tonow, some key technologies are not well known for us,
so it is necessary to install a prototype system in theR&D stage to study the following issues:(1) Developing the backbone of the control systemwith EPICS.
(2) Developing FECs,field buses and intelligent devicecontrollers(3) Designing various device interfaces boards
After that, a well-considered design can be proposed.
References[1] A. Daneels Euro. Lab Part. Phy. 26 Sep 1994
[2] M.Milling, W. Busse Nuc. Ins. & Met. in Phys. Res.
[3] KEK B-Factory Design Report[4] EPICS Release R3.12, APS Argonne