PC-PLC BASED VACUUM CONTROL SYSTEM FOR SUPERCONDUCTING CYLOTRON AT VECC

The superconducting cyclotron’s vacuum control system has been developed at Variable Energy Cyclotron Center (VECC) indigenously. The s7 series of siemens plc system controls the whole process. A pc serves as the interface to the system for monitoring and control. The pc communicates with the plc system via serial port to the communication controller at plc side. There are two distinct part of the pc software. The first one is the vacuum server for the real -time communication with the plc using 3964r protocol and a TCP/IP server to communicate with the second part, the vacuum client. The vacuum client is the control and monitor ing interface for actual operation. It communicates with the vacuum server. The client gets master control depending upon IP address & the level of user authentication. The complete system starting from the fabrication of the Motor control Center (MCC) to the design of the monitoring & control software for pc and the user software for the plc have been developed in house. The heart of the system is plc -pc real-time communication protocol 3964r that needed to be implemented in c/c++ on real-time platform. The windows platform gives a very good graphical environment for human interface at the same time imposes lots of difficulties in implementing the real-time features. However, the protocol has been implemented with a few precautionary measures that windows platform ensures. Therefore, only a soft -real-time system could be implemented. The experience is quite interesting, specially developing the plc -pc real -time communication protocol under windows environment.