The BPM processing system features a history buffer where orbits are stored at a rate of 4kHz. The currently (hardcoded) buffer depth is 4000 samples/orbits.
Since BPM processing is partitioned into two IOCs in B116 and B132, there are two buffers which must be synchronized e.g. by using Spear Events for triggering or by aligning their Spear Timestamps. The respective PVs are 116-BPM:history and 132-BPM:history.