INDUS-2 CONTROL SYSTEM
Pravin Fatnani, J. S. Adhikari, B. J.Vaidya
Centre for Advanced Technology (CAT)P.O. CAT, Indore, INDIA 452 013
fatnani@cat. ernet. inAbstract
Indus–2 is a 2.5 GeV Synchrotron Radiation
Source (SRS) being constructed at Centre For Advanced
Technology (CAT), Indore, India. Electron beam at 700
MeV from booster synchrotron will be injected into thismachine. Indus-2 will raise the beam energy to 2.5 GeV
and store the same. The control system for this facility isbeing developed around a three-layer architecture. The
distinct feature is the use of ‘All-PC’ user interface layer.
The paper presents the overall architecture of thecontrol system.

1 INTRODUCTION
Indus-2 is a 2.5 GeV Synchrotron Radiation
Source (SRS) being setup by Department of Atomic
Energy at Centre for Advanced Technology, Indore. 20
MeV Microtron is used as injector to Booster, which
boosts the electrons bunch energy up to 450 MeV for
Indus-1 (450 MeV SRS) and up to 700 MeV for Indus-2.
The Indus-2 ring is filled with electron bunches till adesirable current limit of 300 mA and then the electron
beam is accelerated to 2.5 GeV at pre-defined rate.
Indus-2 control system is distributed over threelayers of computers viz. user interface computer layer,supervisory computer layer and equipment interface
computer layer. It can also be seen as distributed over
two layers network architecture as shown in figure 1. The
control system architecture is chosen to accommodate thepresent needs and future expansion possibilities. The
distributed architecture with three computer layersinterconnected by two network layers has been widely
accepted because it allows convenient, functional
separation of variety of hardware and software. This inturn results in better speed, performance together witheasy maintenance and upgradation of the overall system.
The upper layer network (Ethernet) provides
interconnection between user interface computers andsupervisory computers. It is mainly governed by therequirements from the point of view user interface,market support and commercial availability. TCP/IP is the
protocol of choice on this network, which is able toprovide services like file transfer, remote file access,process to process communication, etc. Each of thecontrol room computers can access any of the computer

systems connected to the higher level network(supervisory).
Each middle layer supervisory computer system
is networked to various lower layer Equipment Interface
Units (EIU) using fieldbus network. The lower layer
network (field bus) is governed by machine interface
requirement, which is deterministic in nature. The
physical medium is optical fiber to isolate each of theEIUs. The supervisory computers bridging across thehigher level and lower level network are VME bus based
systems. The main task of these system is of supervisory
nature i.e. they continuously command and gather datafrom lower level EIUs and report to the user level as andwhen requested. All accelerator subsystems in the field
are interfaced to microprocessor controlled systems (EIU).
These EIUs are also VME bus based crates. Each EIU
performs predetermined tasks either on request or on
regular basis. One EIU can be interfaced to manyequipments / units with one dedicated interface modulefor each.

2 HARDWARE
As per architecture, hardware is distributed
mainly in three layers.

2.1 User Interface Layer:
Hardware at layer 1 comprises of latest, fastest
IBM compatible PCs as operator consoles, network
gateways, application/file servers and database servers.
With rapid improvement in Intel processor technology
high-end PCs are beginning to exceed workstation
performance. PCs provide added advantage of costeffective solution in terms of support for hardware andsoftware. Win NT workstations will be used as operator
consoles and network gateways, Win NT servers will be
used as network domain controllers and database servers.
This layer will also have few dedicated consoles for
special (fast) application e.g. to access control room
instruments like CROs, frame grabbers for beam position
monitoring systems etc.
Network will be based on Ethernet working at
100 Mbps. It is hoped that ethernet at 100 Mbps will
provide sufficiently good response.

2.2 Supervisory Interface Layer:
Ethernet connectivity is extended down from
User interface computers to supervisory interface
computers. These computer systems are VME bus basedwith Motorola 68040 CPU, running OS-9 (ROM based).
All the hardware at this level is modular. These systems
also comply with industry standard with higher MTBF
rating for continuous operation. These systems are
physically located near control room. Functional divisionat this layer results in one supervisory computer crate foreach accelerator subsystem. Altogether, there would be
about 15 such crates. These systems also provide network
interface for lower level network using a separate
controller board. Profibus is used as field bus for lower
layer network. . Profibus protocol with it’s token passing
and command response mechanisms combined satisfies
the deterministic response requirements.
Connectivity of fieldbus will be implemented by
RS485 to fiber converter and vice versa, thus providing
isolation and noise immunity to different systems. This
isolation is must for accelerator environment as there aremany sources of noise around.

2.3 Equipment Interface Unit:
EIUs are directly interfaced to various
accelerator subsystems like magnet power supplies, RF,vacuum, Timing, beam diagnostics, safety and interlocks,etc. These are also VME bus based computers running
OS-9 with M 68000/68020 CPU. Each EIU consists ofone CPU board, Profibus controller board, VME power
supply and individual equipment interface module. One
such module is needed for each equipment. It consists ofADC, DAC and digital I/O. It also provides opticalisolation to the actual equipment being interfaced. Theremay be nearly 100 EIUs all around the Indus-2 ring.

3 SOFTWARE
As hardware, software is also distributed at threelayers. Client/Server architecture is followed at all thethree layers. User interface layer software, which is also
termed as GUI, handles user interaction and provides ameans of communication between user and accelerator
machine. The basic requirement of open system andfriendly user interaction, should be the main reason forthe selection of software environment. Availability ofvarious development tools and development cost ofdifferent applications should also be considered.
Windows NT is chosen as the software platform
for this layer. It provides powerful, built-in multi-protocol
networking support, multithreading and structured
exception handling besides serving as an excellent
application service platform. It has Unix like features
along with powerful graphical environment and simple

network administration. Remote Procedure Call (RPC)
which is well supported in Win NT is extensively used.
VC++ and Labview are used most commonly as
development tool for application development.
Machine side (equipment interface) mainlygoverns the software requirement for supervisory level.
The main task at this level is to get data from EIU on
regular time interval or on demand and provide a responseto any request made by layer 1 software. OS-9, a real time
multitasking operating system is chosen as the software
platform for supervisory layer computers. OS-9 is one of
the most widely used real time operating systems for
VME bus and comes with good support for crossdevelopment tools. All the program development forsupervisory level will be done at user interface layercomputers in C++. After compilation, modules will bedown loaded on VME crate over network.
At equipment interface layer, software is almost
dedicated to a particular task and confined to a group ofequipments. OS-9 is used at this layer also though withlimited capability. Its basic function is to log equipment
parameters and report its status to supervisory computerwhen demanded. It also controls the equipment as peruser interaction and commands. It also has to manage
many diagnostic tasks related to hardware and reportaccordingly. Device/equipment servers running at thislayer update the latest machine status in the local databaseand send replies to the client requests from higher layer.

4 DATABASE
Indus-2 has distributed computer architecture,
based on client/server model and so is the database ofIndus-2 machine. Microsoft SQL Server has been chosen
as the commercial database platform. Being anotherMicrosoft product, it integrates well with Win NT
platform and VC++ as a development tool and front end.
It supports the distributed client/server architecture quite
well. It provides powerful tools for enterprise-wide
administration, data replication, parallel DBMS
performance, and scalability to very large databases. SQL
Server also provides tight integration with OLE object
technology.
Data for the machine are stored in unified way
and accessed by various application processes (clients)
running on consoles in the client server manner. There are
four categories of databases viz. configuration database,on-line and historic database. Configuration databasestores static data of equipment like calibration constants,
physical dimensions, I/O channel assignments etc. On line
database stores the current status of accelerator subsystemparameters. The data, which are needed for off line
analysis, are extracted from on line database and stored in
the historic database with time-stamp. Alarm databasemanages the detailed record of alarm events occurring atvarious levels.

5 CONCLUSION
Presently, software at various levels is underdevelopment. Till the commissioning starts (at least 18
months from now), there would be much advancement intechnology and easier availability of components in themarket. While implementing we may have to take this
into account to provide a good control system to user. The
network and operator console hardware is more likely tobe affected.

5. REFERENCES
1. Indus-2 Control System - J.S.Adhikari, B.J.Vaidya ICALEPCS 97, Beijing.

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