The system of compressor contains a sub-cooler, a main compressor, a refrigerator, and transfer lines. The SRFC of superconducting comprises of 2 SRFCs, a 2000L Dewar and a valve box. The magnets of superconducting are created of 3 valve boxes, 2 SCQs, a SSM, and a1000L Dewar. The 2 compressor systems of cryogenic were bought from the vendor-Linde Company, which carries out the control of compressor via the PLC of S7-400, WinCC and Pro_bus software. The control system of superconducting devices was built up by the High Energy Physics (IHEP) Institute, the Sciences with Allen Bradley-PLCs of Chinese Academy, VME IOCs and ControlNet.
Overview of the control system
The control system of BEPC/ is according to EPICS, an open source software tools set, applications and libraries built up mutually and employed worldwide. It illustrates the control system structure of the cryogenic at IHEP. The control system of cryogenic is separated into the superconducting control and the compressor control according to the devices of front-end. The interface of operator at the center control room takes care of controlling and archiving of chosen signals, and shows the status running of cryogenic system. The workstations of engineering and VEM IOCs in the control room of local cryogenic can be remotely linked to the PLCs, throughout ControlNet and Pro_bus correspondingly. The PLCs in front end are linked to the actuators and sensors directly. The touch panels local are employed to explain some significant information of the PLCs and can be function to get some actions in the device field.
The communication between the EPICS IOC and the S7-400 PLC
The Cryogenic control of the compressor system is not explained in this article, because it operates WinCC, a system of SCADA, on an industrial personal computer (IPC) and was developed by vendor-Linde Company. But the communication between the EPICS and the system of WinCC is required to incorporate the signals of compressor into the EPICS. The open development kit (ODK) is a package of software, which offers open C application program interface (C-API). We have built up a program of data communication, so that the WinCC data can be contacted or updated by EPICS via C-API of the ODK. An IPC establishing Microsoft Visual C++, WinCC, ODK, and CA Dynamic-link Library serves up as EPICS Channel Access Client (CAC) while a processor of PowerPC working IOC database provides as Channel Access Server (CAS) on the VME IOC.