SurfaceInterval Dive Profile Graph

Sensus logging devices repeatedly record depth and other information throughout the dive. This window displays that information in the form of a graph.


The resolution of the graph depends on the sample interval of the device which recorded the dive, the duration of the dive, and the maximum depth reached during the dive. In addition, any alarms encountered during the dive are superimposed on the graph itself, and on the timelines displayed above the graph.

If the dive entry being displayed was downloaded from a Sensus dive logging device, a temperature profile is displayed as well. SurfaceInterval also allows you to import dive entries from DataTrak for Windows which have been downloaded from Uwatec dive computers. Unfortunately, those computers do not record temperature information on a per-sample basis, so no temperature profile will be displayed for those entries.

The areas on the graph hi-lighted in red indicate alarm conditions which were present during portions of the dive. The time-lines at the top of the page indicate which alarms were reported during the dive, and when. The conditions reported include;
  • rbt - (DataTrak only) The remaining bottom time is insufficient to allow what is considered to be a safe ascent. RBT is based on such factors as remaining air, current depth, nitrogen loading, and the pre-programmed air reserve expected to remain at the end of the dive. Once the diver has ascended to a shallower depth, air consumption tends to decrease, and the decompression profile will change. The RBT value is re-calculated at that point, and the alarm condition will end if conditions allow. Naturally, for entries obtained from Sensus Devices, the RBT alarm should never appear, as these devices are not air integrated. Thus you will only see this alarm for dive entries that were imported from DataTrak.
  • work load - (DataTrak only) The dive computer has detected a condition where the air demand has out-paced the regulators ability to supply air. This is typically termed "over-breathing". Once the diver returns to a normal breathing rate, the alarm condition will clear.
  • ascent rate - The ascent rate is greater that that which is considered safe. This is arguably one of the most dangerous alarm conditions encountered during a dive. If the nitrogen bubbles grow at a rate faster that the body is able to expel the nitrogen through normal aspiration, the risk of decompression sickness (dcs) increases exponentially. Much controversy exists regarding what a maximum "safe" ascent rate should be. However, the consensus seems to be a rate of no faster than one foot per second. Since no "rule-of-thumb" can take into account the condition of the diver, slower is always better, assuming sufficient air supply.
  • deco violation - (DataTrak only) The diver has violated a required decompression stop. The appropriate response to this alarm is to immediately descend to the required decompression stop for the specified duration. Repeated, or severe violations will result in a computer lockout condition, requiring the diver to suspend further dive activities for the duration of the lockout period.
  • decompression - (DataTrak only) The dive profile has generated required decompression stops which must be honored in order to ensure a safe ascent. Decompression diving can be inherently dangerous in that the diver has entered a condition where an immediate and direct ascent to the surface is not safely possible. Failure to honor the specified decompression stops will result in deco violations, not to mention greatly increased risk of decompression sickness, or worse! Decompression diving is generally not sanctioned in so-called "recreational diving" and the diver assumes all associated risk.