From a068ae104175b3e51316456f58bc3098469bb496 Mon Sep 17 00:00:00 2001 From: "Robert C. Helling" Date: Fri, 30 Jan 2015 11:57:57 +0100 Subject: [PATCH] User manual additions for rebreather modes ...in particular for planning rebreather dives. Signed-off-by: Robert C. Helling --- Documentation/user-manual.txt | 30 +++++++++++++++++++++++++++--- 1 file changed, 27 insertions(+), 3 deletions(-) diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index cb77a05..7735246 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1683,7 +1683,7 @@ CCR equipment provide actual measurements of pO~2~, derived from oxygen sensors. In this case the graph for oxygen partial pressure should be fairly flat, reflecting the setpoint settings during the dive. The mean pO~2~ is NOT the mean oxygen partial pressure as given by the CCR equipment, but -a value xalculated by _Subsurface_ as follows: +a value calculated by _Subsurface_ as follows: - For TWO O~2~ sensors the mean value of the two sensors are given. @@ -1691,6 +1691,8 @@ a value xalculated by _Subsurface_ as follows: differences of more than 0,1 bar in the simultaneous readings of different sensors are treated as spurious. If one of the three sensors provides spurious data, it is ignored. +- If no sensor data is available, the pO~2~ value is assumed to be equal to the setpoint. + The mean pO~2~ of the sensors is indicated with a green line, The oxygen setpoint values as well as the readings from the individual @@ -2629,10 +2631,13 @@ This panel allows two type of selections: ** _Default CCR setpoint for dive planning:_ Specify the O~2~ setpoint for a CCR dive plan. This determines the pO~2~ that will be maintained - during a particular dive. + during a particular dive. This is the setpoint that is used at the start + of any CCR dive. Setpoint changes during the dive can be added via the + profile context menu. ** _pSCR O~2~ metabolism rate:_ For a semiclosed rebreather (pSCR) system, this is the - volume of oxygen used by a diver each minute. Set this value for pSCR dive planning. + volume of oxygen used by a diver each minute. Set this value for pSCR dive planning + and decompression calculations. ** _pSCR ratio:_ For pSCR equipment the dump ratio is the ratio of gas released to the environment to that of the gas recirculated to the diver. Set this value for a @@ -2857,6 +2862,25 @@ level is indicated in the _Dive Plan Details_. This duration INCLUDES the transi time to get to that level. However, if the _Display transition in deco_ option is checked, the transitions are shown separately from the segment durations at a particular level. +=== Planning rebreather dives + +To plan a dive using a passive semi-closed rebreather (pSCR), select "pSCR" rather than +"Open circuit" in the Planning tab. This takes the oxygen drop in the rebreather into account. +The parameters of the pSCR can be set in the preferences in the Graph tab. A warning apears +in the dive plan details, if the pO~2~ drops below what is considered a save value. For pSCR dives, +the gas consumption calculation takes into account the pSCR ratio (default 10:1). + +To plan a dive using a closed circuit rebreather (CCR), select the "CCR" option in the PLannig tab. +This makes all user entered segments use the default setpoint value (configured in the Preferences +in the Graph tab). The gases from the gas list are considered to be diluent gases (the oxygen tank is +implicitely assumed to be present). + +Then, individual setpoints can be set for dive segments in the "Dive planner points" table. A zero setpoint +means the diver bails out to open circuit mode for that segment. The decompression is always calculated +with the setpoint of the last manually entered segment. So, to plan an bail out ascent for a +CCR dive, add a one minute dive segment in the end with a setpoint value of 0. The decompresseion +algorithm does not switch decogases automatically in CCR mode (but of course for bail out ascents). + [[S_Replan]] === Modifying an existing dive plan -- 1.9.3 (Apple Git-50)