Power Supply Control for Bepcii Rings and Transport

ABSTRACT BEPCII will construct two rings in the current tunnel to increase the luminosity of the e-e collider. There will be approximately 400 magnet power supplies in the rings. Most magnet power supplies require 100ppm control precision and stability. Only the dipole power supply requires 50ppm control precision and stability. Using a PSC/PSI for the control of a high precision prototype PS it has been proven that the PSI can meet the requirement of 50ppm precision and stability. For easy integration and maintenance, we decided to use the same hardware and software for the control of all PS in the rings. So, control of all power supplies in the rings will be based on PSC/PSI modules and the EPICS toolkits. We will use two types of PSI modules. The 1U rack mount chassis PSI is used for the big PS. The VME bus-sized module VME-PSI is used for the corrector PS. A dedicated VME crate and a VME transition module for the VME-PSI were developed in close cooperation with a domestic industrial company. The VME transition module transfers digital and analogue signals from the backplane to a DB37 connector and a DB9 connector at the rear of the chassis. Therefore, the two styles of PSI modules and the power supplies are connected through the same type of digital/analogue cables. This simplifies installation and integration. The magnet power supplies in the transport line have successfully been controlled using the EPICS toolkit and a VME system connected to the existing CAMAC system via a VME-CAMAC interface board. This paper describes the application of the PSC/PSI for power supply control in the rings for BEPCII. The status of application software development and power supply control is discussed.