The 13th Symposium on Accelerator Science and Technology, Suita, Osakn, Japan, October 2001

A CONTROL SYSTEM FOR THE NEW AVF CYCLOTRON AT CYRIC
M. Fujita, A. Yamazaki, A. Terakawa and T. Shinozuka, CYRIC, Tohoku University, Sendai, Japan
S. Chiba, Y. Ohmiya and N. Takahashi, Su.rnitomo Accelerator Service, Sendai, Japan
M. Tanigaki, Research Reactor Institute, Kyoto University, Osaka, Japan

Abstract
A control system for the new AVF cyclotron (K= 110
MeV) at CYRIC is designed and constructed. The old
AVF cyclotron, which had K=50 MeV and worked for 25years, was manually controlled through the whole hardwiring system. This system was difficult to reuse for thenew cyclotron, since they were designed specially for the680-type cyclotron and its associated devices. Therefore,
we decided to dispose of the old control system, and toconstruct new system. In this report, we describe thecharacteristics of this new control system in addition tothe beam current measurement system, which is also
constructed for the new cyclotron.

1 THE FEATURES OF THE NEW
CONTROL SYSTEM
On the occasion of design for the control system ofnew cyclotron, we have adopted the following guiding
principles; 1) totally real-time computer control system, 2)
robust networking among rooms and instruments forrealize less wiring as possible, 3) only for human safety
by hard wirings.
There are a large number of parameters or statuses tocontrol and monitor of whole cyclotron system, such as
vacuum valves, thermal switches, power supplies, motors
and so on. The PLCs (Programmable Logic Controller),
which are widely used for factory automation, is one of
the best candidates for the purpose. The Ladder programsof PLC, which are described by relay-coil diagrams, arevery powerful for the sequence control and are more
efficient to develop the software. One PLC unit is consistof some CPU modules running the Ladder programs andsome useful modules such as digital 1/0, analog I/0,
Ethernet and so on. With them, one can combine thesuitable modules depend on the purpose. This has aflexibility to modify the system.
A PLC unit can be divided into a main block and subblocks. The main block has CPU modules and it isconnected to sub blocks through the optical fiber cable.
Then these PLC blocks can work just like one long unit.
Since most controlled devices need some hard-wirings tohandle them, it is necessary to locate PLC units close tothem to reduce wirings. On the other hand, it isconvenient to set them far from objects in order to avoid
from radiation damage in the cyclotron vaults and target
rooms. Therefore, we have adopted to detach main block

having CPU modules from the devices, since a CPU
module seems especially sensitive for radiation damage.
However, sub blocks are still located near the devices, thelength of wiring could be held to minimum.
Another remarkable feature of this system is that all
PLC units can be fully handled through the network. Then
TCP/IP protocols, which are the de-facto standard
protocols in the world, are used to establish
communication between PLC and PC. This means no
special device drivers need to handle the PLC. While theLadder Language is very suitable for the sequentialcontrol, it needs some interface programs to operate.
Therefore human interface programs must be developed.
In our cases, all man-machine interface programs havebeen developed by the software Labview from National
Instrument Corporation because of the advantages asfollows. The Labview has a programming environment
like C or BASIC. While other programming environments
use text-based languages, Labview uses a graphicalprogramming language, named G, to create programs inblock diagram form. In addition, Labview includes many
libraries for data acquisition, GPIB and serial instrument
control, data analysis, data presentation, and data storage.
It is efficient to develop highly intelligent programs.
The whole control system have more than twenty PLC
units and more than ten computers, so the heavy traffic
jam will be expected. To prevent this network jam, aserver-clientsystemisconstructed.
Allthecommunications between PLC and clients are made via
the server machine. All information is stored in this server,and it is send to the client PCs as requested. A servermachine can reply requests from many client machines,
because the communication between PC and PC is about
ten times faster than that between PC and PLC.

2 BEAM CURRENT MEASUREMENTSYSTEM
There are more than 50 points to measure the beam
current such as probes, Faraday-cups and beam-stoppers,
where we must measure beam current to operate thecyclotron and beam transport line. Those are distributed
extending over seven rooms (Cyclotron vault and 6 targetrooms). So far, we need analog ampere meter and longcables connected with them to measure beam current.

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The 13th Symposium on Accelerator Science and Technology, Suita, Osaka, Japan, October 2001

A new beam current measurement system, based on
WE7000 from YOKOGAWA Electric Company, isconstructed. The WE7000 is the computer based highspeed measuring device, which has many usefulperformances as an oscilloscope module and a wave
generator module and so on. In addition, a special module
for current measurement is available. It has 4 CH input
and has a wide input range from I nA to 10 rnA full scale.
At present, more than fifteen modules are available andlocated near the measuring points. No extra cables acrossthe rooms are required to measure the beam current sincePl.CcSUMMARY
The new control system for the new AVF cyclotron has
been almost complete, and working without troubles. The
first beam acceleration of a-50 MeV was succeeded andthe new AVF cyclotron is now used for regular work.

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all stations with modules are connected through theexclusive optical fibers.

ulink

Gxnrol room

Pl.C

H..C

optical fiberr-- _rI

II'To the target room

_J__I
III
I

Target Room

II
I
I
I
I

:WE?croI: optical fiber
I
I~---------I,----~~Pl.C

To Gxnrolled target

Rtradey C1Jp
& Beam s«HJer

Ustributcr

Figure 1: The diagram of the new control system.

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