# Filaments

DraMS has two filaments, filament A and filament B.

### On Time 

Filament A and Filament B on time are determined by measuring the
amount of time that HFB_FIL_ON_A or HFB_FIL_ON_B are 1.

### Cycles 

Filament A and Filament B cycles are determined by counting the number
of times the filaments transition from off to on. A few notes about the
algorithm:

-   if the digital status packet indicates that the SEB is off, then the
    state of the filaments is considered to be off.
-   a filament is considered to be on if if its on "on bit" is set to 1, and if the FIL_VMON is above 2.5V. Otherwise, it is assumed to be off.
-   if the FIL_VMON is not being sampled, then only the "on bits" are used to determine if the filaments are on.