The voltage level, in volts, of the main power bus (normally between 26-35v).
P-2021 Bus Current Low
The current level, in amps, of the main power bus (current load).
P-2009 Cruise SA Current
The current level, in amps, coming from the cruise stage solar arrays.
P-2006 Shunt Current
The current level, in amps, going into the shunt limiter (excess current).
P-3035 18 Voltage
The battery voltage (18 cell silver-zinc rechargeable battery).