Man - Machine Interface for Power Supply Control for Electron Cyclotron
Resonance Ion Source
C . D . Datta , S . K . De and D . Sarkar
Varable Energy Cyclotron Centre , Department of Atomic Energy ,1/AF, Bidhannagar , Calcutta 700 064 , India
Abstract
Man - Machine Interface (MMI) becomes more andmore important in supervisory control system as a rapidtransformation in system monitoring and control is taking
place due to evolution of state of the art tools andtechniques. This paper describes the design andimplementation of MMI system for control and monitoringof magnet power supply for Electron Cyclotron ResonanceIon Source (ECRIS ) at Variable Energy Cyclotron Centre(VECC) , Calcutta.
1 Introduction
A large number of magnets have been installed andcommissioned to guide the beam from ECRIS to theCyclotron central region at VECC, Calcutta. All thesemagnets need to be powered by highly stabilised direct
current to maintain the alignment of the beam. Our
objective is to design and develop a powerful MMI tocontrol and monitor the operation of these power supplies.
2 Man -machine interface system
The function of the MMI system is summarised in fig. 1.
The MMI subsystem sends requests and obtains inputs andstatus information through data acquisition subsystem. The
main aim of the MMI is to allow the operator fast andconvenient access to information. It provides rapid
notification of important events through display and alarm
generation. It also saves the information on hard disk foroffline analysis. In addition to displays, hard copy devices
like printers are used to notify the operator of eventsoccurring in the system to provide a permanent record ofsystem activity.
3 System configuration
The system has been developed based on PC AT / 486 DX2 hardware platform running Windows 3.11 and Visual
Basic as the graphic user interface tools. Data from thepower supply system is received through thecommunication port of the PC with RS232C serialinterface. The communication parameters of the power
supply are set up accordingly by proper switch settings.
The link between the computer and the power supply isdone through a 25 pin D-connector. All these connections
are optically isolated. Visual Basic is chosen due to its
simplicity for writing programs for windows applications.
4 System features
The system displays the operator control panel in themain form which can be connected and disconnected fromthe power supply without affecting the operation of thepower supply.The following operations can be controlledfrom the panel (fig. 2).
- Main power ON / OFF- Current setting
The coarse button will change the current by 10% foreach turn. The first two digits only on the display willchange.
By turning the medium button , the current setting willbe altered by 0.1% for each turn. Digits 3 & 4 of thedisplay will change.
The fine button will change the current setting by 10
ppm for each turn. The last two digits on the display willchange.
− Display of the actual current in both text as well as inammeter form.
− Ready LED indicates when the actual output current
is equal to the set value within +/- 200 ppm.
− Display of the actual current signal and its drift fromthe set value.
The function of the second form is to monitor the statusof the various interlocks like waterflow, etc. It is obtainedby sending a request and reading a status word of 24
character length. The failure of any of the interlocks isindicated by the change of color to draw the operator’sattention. The third form monitors the internal parameterslike +5 V, +/-15 V , passbank drop, etc, which are essential
for proper functioning of the internal circuits.
The system has also been designed to offer a powerfuland comprehensive set of analysis and visualisation
functions. It provides the history of the current output, drift
and the statistical parameters like mean, rms, standard
deviation and histogram.
A very important aspect of any control system issecurity. This is provided by incorporating a password
feature at the entry level so that unauthorized personnel
can not enter into the system.
5 Conclusion
This system has been developed as a subsystem of theHuman Computer Interface for the computerised control ofthe Electron Cyclotron Resonance Ion Source (ECRIS) at
Calcutta [6]. The system has been working successfully
with one DANFYSIK 8000 Series Magnet power Supply.
The system provides better security of the operation of thepower supply. It also saves an uncountable amount ofmanpower. The system is open for upgrade to connect
multiple power supplies through RS422 interface which
will overcome the limitation of distance with RS232C.

Acknowledgments
The authors would like to express their sincere gratitude
to Dr. Bikash Sinha, Director, VECC for his inspirationand constant encouragement. The authors would like toexpress their thanks to Shri Subimal Saha without whose
help the project would not have been completed. Theauthors would also like to express their thanks to Dr. D.K.
Bose for his kind cooperation.
References[1] P. K . McBride ‘Programming in Visual Basic’ BPB
Publications.

[2] Magnet Power Supply 853 System 8000 Manual
DANFYSIK, JYLLINGE, DENMARK.
[3] Richard Lai , ‘Real Time Supervisory control andData Acquisition Systems’, CSI Communications,April 1986.
[4] Microsoft Visual Basic Programmer’s Guide,
Microsoft Corporation.
[5] Microsoft Visual Basic Language Reference,
Microsoft Corporation.
[6] Tapas Samanta , C . D . Datta and D . Sarkar ,‘Human Computer Interface for the Computerised
Control of Electron Cyclotron Resonance Ion Source(ECRIS) at Calcutta’, presented at the ICALEPCS‘97at IHEP, Beijing.

Fig. 1 The function of the MMI system

Fig. 2 The control panel