Seiko DH33 Manual - Page 13

EXPLANATION OF THE TERMS English Terms Altitude rank Residual nitrogen indicator Explanation The pressure sensor measures the atmospheric pressure at regular intervals, and the watch indicates the altitude rank in four levels from 0 to 3. The measurable range of altitude is 0 ~ 6,000 m (19,700 ft). If the measurement is outside this range, the altitude rank indicator flashes. The amount of nitrogen absorbed by the diver's body is indicated graphically in 10 levels from 0 to 9 by the number of bars shown on the display. When all 9 indicator bars light up, the watch calculates decompression diving. Desaturation time The time required for the excess amount of nitrogen accumulated in the diver's body during a dive to be eliminated completely. It is indicated in hours and minutes, and the watch counts it down. Desaturation is considered to be completed when the countdown is over. FO2 (Percentage of Oxygen) Nitrox mark The percentage of oxygen in the gas mixture of the scuba tank, which the diver needs to set for the watch before diving. For diving with air, "Air" (21%) should be set. FO2 can be set from 22% to 50%, and if a value within this range is set, the watch calculates nitrox diving, and the nitrox mark "Nx" is shown on the display. The set FO2 is recorded in the dive log function. If the watch is left untouched with "Nx" shown on the display after a dive, it starts flashing on the next day to indicate that FO2 should be re-set. Otherwise, "- -" is shown in place of the previous FO2 setting, and the watch cannot be used for diving. Depth rank For planning a dive, the depths from 9 m to 48 m (30 ft to 160 ft) are divided into 14 ranks in 3 m (10 ft) increments. 24 Terms No-decompression limit (NDL) Explanation The maximum time during which the diver can stay at the current depth or in the selected depth rank without decompression procedure. The watch indicates NDL up to 200 minutes. In the DIVE PLAN display, if you choose a depth rank where the partial pressure of oxygen exceeds 1.6, "- -" is displayed in place of NDL. Log No. The order of diving data stored in memory. Details of up to 30 dives can be recorded. The log data of a dive is shown in two separate displays. They have different log Nos. such as "30-1" and "30-2". Number of dives on that day Entry time The number of dives made on the same day. It is recorded in the dive log function. The time when the dive is started. The watch records the time when the diver descends to a depth of more than 1.5 m (5 ft). Exit time The time when the dive is finished. It corresponds to the hour and minute when the diver ascends to less than 1.5 m (5 ft) underwater. Average depth Maximum depth The average depth is calculated from the depth data measured during a dive. It can be checked in the dive log function. The greatest measurement of depth during a dive. English EXPLANATION OF THE TERMS Terms Explanation Current water temperature Water temperature at maximum depth The watch measures the water temperature every minute in 0.1° C (1° F) increments from -5.0° C up to +40.0° C (23° F up to 104° F). If the measurement is outside the range, "Lo" or "Hi" is displayed. The water temperature at the maximum depth is recorded in the dive log function. Residual nitrogen at end of dive Residual nitrogen at the end of a dive is recorded in the dive function and indicated graphically by the number of bars. Residual oxygen at end of dive Residual oxygen at the end of a dive is recorded in the dive function and indicated graphically by the number of bars. Decompression stop depth The depth at which the diver should make a decompression stop. It is calculated on the basis of the diving data collected during the dive, and selected from 15, 12, 9, 6 and 3 m (50, 40, 30, 20 and 10 ft). If the diver ascends to a depth shallower than the indicated depth, a decompression stop violation warning is given. Terms Decompression stop time Explanation The time period during which the diver should stay at the decompression stop depth. It is calculated on the basis of the diving data collected during the dive, and is counted down while the decompression stop is being made. Total ascent time The minimum time required to stay underwater before surfacing, including the decompression stop. PO2 (Partial pressure of oxygen) Oxygen limit indicator PO2 is calculated on the basis of the depth and the FO2 setting (percentage of oxygen in gas mixture). When PO2 exceeds 1.5, a warning is given. The amount of excess oxygen in the diver's body is indicated graphically in 9 levels by the number of bars shown on the display. In nitrox diving, the diver is exposed to higher levels of oxygen. If all the indicator bars light up, ascend to a shallower depth, as you are in danger of suffering from oxygen toxicity. 25