Use of the sequencer for run permit calculations

["Peregrine M. McGehee" <peregrine@lanl.gov>]

Aloha,
I am considering the use of the EPICS sequencer (SNL) for implementing the interlock logic for our run permit system. My questions are:
o has anyone done this before?
o are there definite cons to using SNL (determinism issues??) - we need timing <= a few 100milliseconds including network and CA delays - but this _not_ a safety system.

The pros are:
o human readable source
o ability to assign meaningful labels to process variable names
o relatively transparent use of CA client API
o compiled (which means faster than other solutions such as the _expression_ parser used in the Calculation record)
o straightforward mapping of run permit logic onto program code:
state sets map to beam permit, RF permit, and high current permit
states map to accelerator operational modes
o ability to re-configure without IOC reboot

Thanks,
Peregrine

Peregrine M. McGehee Project Engineer: LEDA Control System
(505) 667-3273 peregrine@lanl.gov
LANSCE-8 Controls & Automation Los Alamos National Laboratory