value| orientation| abbrev
400| Up| Up
401| Down| Down
402| Vertical. sense not indicated| Vert
500| Radial, inward| Radl
501| Transverse, 90 deg CW from radial | Tran
600| Longitudinal (relative to structure)| Long
601| Tangential (relative to structure)| Tang 
700| H1 (horiz. sensor, azimuth unknown) | H1
701| H2 (horiz. sensor, azimuth unknown) | H2
1001-1360|Horizontal azimuth relative to Chn 1, if absolute not known|n/a
2000| Other (described in comments) |Othr