The facilities of NSLS (National Synchrotron Light Source) at front-end systems are VME-based computers and mostly use VME I/O peripheral boards for data acquisition and hardware control. With the option of the hardware engineers of NSLS to utilize PLCs for the power supply systems, beam line status, and RF the front-end systems are being advanced to interface with PLCs.
The NSLS facility has two storage rings, one for X-ray at 2.8 Gev and the other for VUV at 800 Mev and a joint injection system (a Booster ring and a Linac). The NSLS control system at has a two-level architecture involving of HP workstations. The link of communication between the 2 levels is high-speed Ethernet. The all of front-end systems are VME-based computers operating software real-time recognized as the Control Monitor of NSLS, except for a couple systems that use PC-based, which is developed around the real-time operating system of VxWorks. The computers of front-end systems are referred to as Micros at NSLS.
A basic micro contains of a VME-based computer single board with Ethernet Controller, a GPLS (general purpose light source) board, and a battery-backed up for memory board. The GPLS offers an ASCII video display generator, timers, serial ports, and an interrupter module. Based on the equipment to be monitored and PLC controlled, a variety of type peripherals of VME I/O are used. Instruments with Camac and GPIB and RS232 interfaces controllers are also carried out.
Some systems contain analog signals more than 1000 analog signals. When all the boards cannot be put in an individual VME crate or when hardware units controlled by a micro are dispersed around the ring, multiple barred enclosures with bus expanders have been used. Because of the cost very expensive of the VME products the micros supplied only the data and controls acquirement vital for the ring operations.