Display Detail
1. Gas name, including CO, H2S, SO2, or O2
2. Question mark (perform operation?)
3. OK status indicator (or accept number entry)
4. Concentration unit, e.g. ppm, %, mg/m3, etc.
5. Battery charge status
6. Alarm type indicator
7. Zero in progress indicator
8. Calibration in progress indicator
9. Concentration or other numerical value