Data Acquisition System with Shared Memory Network

The SPring-8 control system provides data acquisition software called Poller/Collector for periodic data taking. Its polling scheme does not support taking data synchronized with an event, and simultaneity in the data from the different VME systems is not guaranteed. Recently, requirement for fast and event-driven data acquisition has increased, and the synchronization of a set of data from the different VME systems is requested. We added new data-taking software to the standard framework with a shared memory network. We designed the software on the VME by updating the original framework that was already used for feedback control. The data filling process on a PC stores sets of the synchronized data on a shared memory board to the database. The shared memory boards provide 250Mbit/s transmission rate and are linked with optical fiber cables. We will install the system to the linac beam position monitors data acquisition as the first application.