Welcome to Control Systems!

The EPICS-based SNS Control System is consistent with the established " standard mode" for accelerator controls.

  • There are approximately 150,000 Process Variables (PVs).
  • Most devices are interfaced using standard Allen-Bradley ControlLogic™ Programmable Logic Controllers (PLCs).
  • Control and monitoring for all major accelerator subsystems, including magnet power supplies, radio-frequency, cryogenics, vacuum, cooling and many special devices is integrated using approximately 150 VME/VXI-based Input/Output controllers (IOCs).
  • Control and monitoring of beam instrumentation devices is provided by approximately 300 PC-based "Network Attached Devices" (NADS) that are configured to look to the system like standard EPICS IOCs.
The system is also responsible for several "global subsystems", including a central control room, overall timing and synchronization, machine protection and an extensive switched TCP/IP infrastructure on a Gigabit Ethernet backbone.

Physics applications are developed using the XAL toolkit and are interfaced directly to the EPICS infrastructure.

Generic applications for archiving and alarm handling come from the standard EPICS toolkit.

The controls group is also responsible for the Personnel Protection System (PPS) which provides access control and radiation monitoring for both the accelerator and the target systems.


Like the SNS accelerator itself, the control system was developed by a collaboration of control system developers at three of the SNS partner laboratories.
  • Lawrence Berkeley National Laboratory (LBNL)
  • Los Alamos National Laboratory (LANL)
  • Brookhaven National Laboratory (BNL)
  • Oak Ridge National Laboratory (ORNL)
Our partners developed control systems to accompany the subsystems being delivered by their home laboratories.
  • front end subsystems at LBNL
  • linac subsystems at LANL
  • ring and timing subsystems at BNL
  • target, cryogenic, and remaining global subsystems at ORNL
As these subsystems were handed over to the "home team" at ORNL, the role of the partners was reduced from leading to mentoring and finally to occasional consulting. Final commissioning and operation is in the hands of the ORNL Controls Group, introduced in these pages.

SNS Control Room