LINUX/PCI: THE ESRF BEAMLINE CONTROL SYSTEM MODERNISATION

The ESRF control system was developed more than 10 years ago, using VME Motorola 68000 CPUs with OS/9, connected to control HP/Sun workstations (WS) through TACO. Needs of faster experiments and change to supported hardware require the modernisation of beamline (BL) control. Industrial PCs with Pentium III CPUs running Linux have been chosen as main control PCI crates. Support of current VME instrumentation is ensured through PCI/VME bus couplers; cPCI crates can also be controlled by PCI/cPCI bus extenders. TACO/TANGO is used to export the instrumentation control through the network. This system is very flexible in terms of configurations; it can control a simple BL from a single PC, and it can fit more complex experiments with dedicated PCI/cPCI crates controlled by a client WS. Fast acquisitions are implemented with a soft real time, kernel-based mechanism called Hook, which allows simultaneous reading of PCI, cPCI and VME cards. SPEC is used as main control application, now featuring a server mode that allows PyQt GUIs to easily access the hardware from a higher level.