ca server event filtering generalize payload upgrade

Currently, the subscription update event queue in the
EPICS server is capable of carrying payloads consisting
of a channel’s value, time stamp, and alarm state. The
complexity of the LANSCE macro pulse beam structure
requires unique capabilities from the control system,
which is currently a hybrid of EPICS and the original
VMS-based LANSCE Data System. A homogeneous
EPICS based system with a tool based approach to the
development of modular application programs is the
favored post upgrade configuration, but this evolves new
requirements for EPICS. Specifically, EPICS Channel
Access (CA) Clients must dynamically specify the
LANSCE macro pulse beam gate combinatorial, and a
time window, to be sampled when they subscribe. EPICS
upgrades fulfilling these requirements, including generic
software interfaces accommodating site specific event
queue payloads and client specified subscription update
filtering expressions, will be described.