E881 Parameter Control and Generation Specifications

Drift, alignment and hotwire parameters are store in Mapmanager map-files, on a run-by-run basis. These are stored as map items, and are referenced by a unique key, with:

 Key = Tape*1000 + Run

For runs with parameters which are identical to previous runs, no new (duplicate) items are stored; the convention is to use a stored parameter for a particular run (referenced by that run's Key) from the highest-valued Key which is equal to or less than the particular run's Key. So, the lowest-valued Key must have all items stored, but higher valued Keys have only those items which have changed; this avoids duplicate storing of parameters, as well as other difficulties associated with the general problem of maintaining multiple copies of parameters.