[Bteam] Arc 2 energy lock vs FFB

[Michele Joyce]

Is there a reason that we are using 2L19 for the FFB slow lock, and 2L20 
for the Arc 2 energy lock?
Should the Arc 2 lock be changed to use the same zone?

When OPS sends witness beam when Hall A is down, the Arc 2 energy lock 
is used. When Hall A comes back up, FFB starts using 2L19 to correct for 
the imbalance between Arc 2 and BSY1C. 
http://opsweb.acc.jlab.org/CSUEApps/elog/3-0/entry/1501609


Michele