I think I have figured some stuff out. It looks like each channel is assigned two bits. If both bits are set to '1' the channel is healthy. Of course the display output I was using was configured to show data in double format and therefore for two channels:
3 = channel 1 is healthy
12 = channel 2 is healthy
15 = both channels are healthy
For the above output [8; 12; 0]; this suggests neither channel have a healthy excitation and both channels have a healthy output based upon the excitation. Of course this is 0V because there is no excitation. I have yet to figure out exaclty to what the '8' refers but it would suggest the internal test has failed completely on channel 1 and partially passed on channel 2:
Ch2 Ch1
8 4 ¦ 2 1
1 0 ¦ 0 0
