Indus-2 Control System(J.S.Adhikari,B.J.Vaidya)

Centre for Advanced Technology, Indore, INDIA(E-Mail : jsa@cat.ernet.in)
1 Introduction
Indus-2 is a 2 GeV Synchrotron Radiation Source (SRS)
being constructed by the Department of Atomic Energy at
the Center for Advanced Technology, Indore. A 20 MeV
Microtron is used as an injector to a Booster, the booster
raises the electron bunch energy up to 450 MeV for Indus1 and up to 700 MeV for Indus-2. The storage ring isfilled with electron bunches untill a smaximum current of300 mA is reached. It then accelerates them to 2 GeV at
pre-defined rate.
This paper describes the control system of Indus-2.
The control system architecture has been chosen toaccommodate present needs and future expansion in termsof functionality and capability. The system should also
address the upward trend in technology. Following aresome of the guidelines used in the design of the control
system and its architecture:-The architecture of the control system should be
modular and distributed at all levels.
-Standard tools should be used for development.
-Commercially available hardware should be used toease in replacement and maintenance.
-Networking of subsystems should be maximized.
-There should be provision to accommodate various
instrument supplied by different agencies.
- The control system should be expandable and be able toaccommodate new technologies.
-Fail safe operation.
2 Architecture
Indus-2 control system is distributed over three layers ofcomputers : user interface layer, supervisory layer andequipment interface layer. It can also be seen as
distributed over two network layers as shown in the figure.
The upper layer network provides interconnection
between the user interface and the supervisory computers.
Selection of the upper layer network is mainly governed by
the requirement from user interface, market support andcommercial availability. The higher layer network has tobe ‘open’ in the sense that different kinds of computersfrom different suppliers and running different operating
systems will be connected to it. This leads to use ofsophisticated and standard protocols, such as TCP/IP,
running over a Local Area Network and able to provide
services like file transfer, remote file access, process toprocess communication. In the control room, consoles areprovided for operator interface and software development. Dedicated servers are also connected to thenetwork. Each of the control room computers can accessany of the computer systems connected to the higher levelnetwork(supervisory).

The lower layer network (field bus) is governed bymachine interface requirements, which is deterministic innature. It connects supervisory computers to equipment
interface unit via a field bus. Optical fiber is used to isolate
each of the EIUs. The supervisory computer bridging
across the higher level and lower level networks are VME
bus based systems. The main task of these system is of asupervisory nature i.e. they continuously command andgather data from lower level EIUs and report to the userlevel as and when requested. Any equipment with astandard interface (GPIB, Serial etc.) can be connected tothe network via VME modules or PC interface boards.
All equipment in the field are interfaced to microprocessor
controlled systems (EIU). These EIUs are also VME bus
based crates. Each EIU performs predetermined taskseither on request or on regular basis. One EIU can beinterfaced to many devices with one dedicated interfacemodule.
3

HardwareHardware is distributed in three layers.

3.1 User interface hardware
Hardware at layer 1 are servers, operator consoles andconsoles for software development.
Powerfulworkstations and PC's from different vendors are good
choices at this level. The gap between workstations andPCs is narrowing down with improvement in technology.
A PC provides cost a effective solution in terms of support
for hardware and software. Availability of software andhardware is also in favour of PCs. For Indus-2 highperformance PCs for both servers and operator consoles isbeing considered.
At this time two servers are
considered to be sufficient for file services, databaseservices and also to provide redundancy with auto
switching capability. Services are also required to provide
autobackup, controlled access and a warning feature forhard disk, network failure . Operator consoles should
provide an excellent graphic environment for Graphical
User Interface (GUI) development. 64 bit PCI bus basedgraphics accelerator cards with high resolution monitors
well satisfy this requirement. Hardware support for
multimedia may be considered for user interface softwaredevelopment. Multi-homing interconnection via a switch
can be implemented for expansion and higher transmission
rate requirements. The accelerator control network(AcCNET) is based on Ethernet (IEEE 802.3 standard)running at 10 Mbps. Ethernet is not deterministic at higherloads but when the load is low, 30% to 40% of the total
capacity, it is almost deterministic. Also, ethernet is
widely accepted in industry and variety of applications aredesigned around it. Some of the dedicated systems at

control room may be as follows.
-High performances servers.
-Operator console with GUI.
-Dedicated consoles for program development.
-General purpose consoles.
-Dedicated fast CROs, Synthesiser, PA system etc.
-Display monitors and terminals as per user
requirements.
3.2 Supervisory layer hardware
Ethernet connectivity is provided at the supervisorylevel computers. These computer systems are VME bus
based with a Motorola 68040 CPU. All the hardware at
this level is modular. These systems are industry standard
with a high MTBF rating. These systems also provide
network interface for the lower level network using aseparate controller board. Profibus is used as a field bus forthe lower layer network. Profibus is token passing andsatisfies the deterministic requirement for equipment
interfaces. These system are physically located near thecontrol room.
Connectivity of the 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 an accelerator environment as there
are many sources of noise.
3.3 Equipment interface unit
EIUs are interfaced to various accelerator subsystems
power supplies, vacuum, RF systems, safety and interlocks.
It is also designed around VME bus structure. It consistsof one CPU card, Profibus controller board, VME power
supply and individual equipment interface modules. 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 machine.
4 Software
As with the hardware, software is also distributed atthree layers. Upper layer software (GUI) handles userinteraction and provides a means of communication
between user and accelerator machine. There is no defacto
standard for this purpose, because of fast development andnew emerging technologies. The basic requirement ofopen system and friendly user interaction, should be themain reason for the selection of a software environment.
Also the availability of tools and development cost ofdifferent applications should be considered.
Unix is being used by many control system designers forsoftware development. We have deviated from Unix toWinNT which provides almost Unix like features alongwith powerful graphical environment. VC++ will be used
for application development. It provides
the MDIenvironment needed for the control and data acquisition
system. Layer 1 software mainly deals with user
requirements and should respond to each of the user
action. Since the application software may be running witha non real time operating system, the response to userinteraction should be within human acceptable limits 500
msec. to 1 sec. Similarly database updating may be at a
rate of 1 sec. to 1 hr. or more as the requirements.
Software requirement for supervisory level is mainly
governed by the machine side. The main task at this levelis to get data from EIU on regular time intervals or on
demand .A real-time operating system is required at thislevel. In the field of real time system software there aremainly three options for consideration i.e. VxWorks, pSOS& OS9. OS9 along with cross development tools waschosen. OS9 is one of the most widely used real time
operating systems for VME bus. All the program
development for supervisory level will be done in C++.
After compilation, modules will be down loaded to theVME CPUcrate over the network.
EIU software is dedicated to a particular task andconfined to a group of equipments. Its basic function isto log equipment parameters and report equipment status tothe supervisor layer when demanded. It also controls
the equipment as per user interaction and commands. It
also has to manage many diagnostic tasks related tohardware and report accordingly (like ADC, DAC
calibration, channel testing with reference source provided
on board etc.).
5 Database
Indus-2 has a distributed data base architecture.
Configuration of the database will be done at a single point
to avoid conflicts. In a distributed system some data may
be held in different forms in different parts of thesystem. Indus-2 control system will have a dedicateddatabase server on the network. A general purpose
commercial database will be used to store parameters andequipment data for the whole machine. Data for themachine is stored in a unified way and accessed by various
processes running on consoles in the client server manner.
On line and off line applications distributed in several
systems can store and retrieve the data from the databaseover the network. On line applications have a higher
priority than off line applications. The database manages
three categories of databases , consistent, on-line andhistorical database. The consistent database stores stabledata of equipment like calibration constants , and physicaldimensions . The on line database stores the current statusof accelerator parameters. The software for this purpose
should be fast enough to cope with the number of channels
required to be updated per second. The data ,which isneeded for off line analysis, is extracted from the on line
database and stored in the historical data base with a timestamp. The historical data base is an archive of data which
includes ambient temperature, LCW temperature, alarm
status, beam current etc. SQL support is a requirement fordata retrieve from the database.
6 Conclusion
The commissioning of the proposed control system will
be done after completion of the civil work. This may
take nearly 18 months or more. Till that time there may be
many advancements in technology and easier availability

of components in the market. If the load on the network
increase,the main network may need to be changed to
FDDI. User consoles or networks will also be connected tothe main network when the machine gets commissioned.

physics laboratories - Raymond Rauch.-ICALEPCS 93,Berlin.
[2]The Elettra control system - methodology, architecture
and technology - D.Bulfone, M.Mignacco, R.Mazzurco.
[3]Control system of Spring 8 storage ring - K.Tanaka andothers.
[4]20 MeV Microtron control system - J.S.Adhikari,
B.J.Vaidya, Y.Seth - ICALEPCS 95, Chicago.

References[1]Tutorial on standard field buses - Application in

INDUS-2 CONTROL SYSTEM ARCHITECTURE
CATNETOPERATOROPERATORCONSOLECONSOLESERVERSERVER

USER I/F(LAYER 1)

PS(LAYER 2)

RS 485TOFIBERCONVERTOR

Fig. Indus-2 Control System Architecture.

UNIT I/F
MODULE(ADC+DAC+I/O)

MEMORYMEMORY

68000 BASE
CONTROLLER
68000 BASE
CONTROLLER

UNIT I/F
MODULE(ADC+DAC+I/O)

PROFI I/F
PROFI I/F~~~~~~MEMORYMEMORY

UNIT I/F
MODULE(ADC+DAC+I/O)

68000 BASE
CONTROLLER
68000 BASE
CONTROLLER

UNIT I/F
MODULE(ADC+DAC+I/O)

PROFI I/F
PROFI I/F~~~~~~UNIT I/F
MODULE(ADC+DAC+I/O)

MEMORYMEMORY

UNIT I/F
MODULE(ADC+DAC+I/O)

PROFI I/F

68000 BASE
CONTROLLERPROFI I/F

68000 BASE
CONTROLLER~~~~SERIAL I/F
GPIB I/F~~FIBER TORS 485
CONVERTOR

INDUS-1
NETWORKSUPERVISORYMEMORYETHERNET I/F

PROFI BUS I/F

68040 CPUBRIDGECONTROLLER

PSETHERNET I/F

PROFI BUS I/F

68040 CPUCONTROLLERPSMEMORYETHERNET I/F

PROFI BUS I/F

68040 CPUCONTROLLERMEMORY(AcCNET)ETHERNETEQUIPMENT I/F(LAYER 3)