How to use the PYDPLANner

This document is work in progress and incomplete.

Modes and main features

PYDPLANner calculates the Buhlmann 16 tissue compartment decompression model throughout a configured or imported dive profile. The resulting model states throughout the entire dive profile can then be explored by using various graphical views to the data.

PYDPLANner can be used in 3 main modes:

The main window

mainwin-shorturl

The application main window is divided into tabbed control panels on the left hand side, and tabbed viewer panels on the right hand side. On top there is a menu, which is still not doing much, but has planned future use.

By default the application starts in Calculation mode in Plan tab selected on left side panel, and Profile view on the right hand side.

The main window has a minimum size, but by dragging edges or corners it can be resized to any size. It can be maximized and minimized or closed.

From menu File/Exit one can close the application. Or by CTRL-Q.

There is a slider widget between left and right side, which allows changing the proportion of side. But each side has a minimum widht and after pulling beyond that the entire panel goes hidden. The hidden panel can be dragged back from pulling the edge.

Control panels (left side)

By clicking a tab one can navigate to one of the following control panels:

Plan

By clicking a tab one can select one of the following operating modes and related controls

Calculation mode

WARNING: DO NOT USE FOR REAL DIVE PLANS, THIS SOFTWARE IS NOT TESTED AND INCOMPLETE WORK IN PROGRESS

The user configures bottom depth, bottom time and gases to use, the application then calculates the Buhlmann model throughout the dive and produces a decompression schedule that does not violate Gradient Factor based ceiling.

Above the tabs there are two widgets that allow controlling the:

Changing any of these will immediately recalculate and redraw views. Feedback is immediate so one can easily see what changes take place when modifying parameters.

Under the Calculate tab there is a printout of calculated deco stops in tabular form. The profile can also be see graphically on the Profile view.

Below this the total runtime and average depth are shown. At the bottom one can configure the descent and ascent rates in m/min. Changing any of these will immediately recalculate and redraw views.

TODO:

There should be tickbox that allows selecting 3 meter stop on/off.

Custom mode,

The user can configure a custom dive profile and see the resulting Buhlmann model states.

Up to 9 deco stops by depth and time can be configured in this mode to create a custom profile. The user can then explore what such a profile looks in the Buhlmann model.

Import mode

This mode is not yet implemented and is in the backlog of future development.

The user can import a real dive profile from a dive computer or dive logging software and see the resulting Buhlmann model states.

Tanks

This panel allows selection and configuration of gases and tanks. Each tank is shown in one column, and on each row one can configure if the tank is used and what are tank and gas parameters.

Up to four tanks can be selected and configured to the dive:

Following tank parameters can be configured or viewed:

TODO:

Warnings etc..

Model

Allows controlling details of the decompression model.

At this time model selection actually does nothing and model C is always selected. The difference between models are:

Gradient Factors

Using Gradient Factors adds conservatism to the model. The original Buhlmann model would be setting Gradient Factors to 100/100.

Here are some articles about Gradient Factors:

The Gradient Factor LOW sets the deco ceiling on ascent until the first deco stop is reached. After this the Gradient Factor is increased linearily such that on surface the deco ceiling is calculated using Gradient Factor HIGH.

Simply put, the lower you set GF LOW, the deeper you will get deco stops. A higher GF LOW will not produce deep stops. The lower you set GF HIGH, the longer decos you will get at 6 to 3 meters.

Common Gradient Factor settings (LOW/HIGH) are:

Viewer panels (right side)

On the right side one can select a tab to view any of the following views to the data.

Profile

This view shows:

dive profile

The dive profile is plotted in filled blue with runtime in minutes on x-axis starting from left. Depth is on y-axis with depth growing downwards to bottom.

The thick green line is the calculated deco ceiling in 3 meter steps. Above it one can see the unrounded deco ceilings from all tissue compartments in different shades of green. The deco ceiling shown takes gradient factors into account.

The tank pressures are also plotted with gas changes, star end end pressures of tanks.

The running average depth is plotted in grey.

On right bottom quadrant the ceiling margin is plotted.

partial pressures panel

Plot of Oxygen, Nitrogen and Helium partial pressures at this profile. Oxygen and Nitrogen limit lines are shown:

TABLE

This panel shows numerical data of the dive profile in a table. Each point in the dive profile is on a single row, whereas columns show data of that point. If you hover the cursor over a column heading, then you will see a longer explanation of the column data.

The columns are

Following columns show the ceiling in meters for each tissue compartment number ffrom 1 to 16.

PG

This panel shows a Tissue Compartment pressure graph, where X-axis presents the Tissue Compartment pressure vs. Ambient Pressure (Depth) on Y-axis.

Diagonal lines plot the M-values of each tissue. Each tissue is shown in different color.

3 plots are available:

TODO: The M-value lines are not plotted correctly yet. Needs fixing.

TC Pressures

This panel plots the pressure on individual Tissue Compartments for Helium and Nitrogen separately.

The depth profile can be seen in the background.

Bars

This panel shows the tissue compartment pressures at a selected run time of the dive. You use the slider at the top to select the run time. The respective tissue compartment pressure is shown in bars growing downwards. The green part of the bar is Nitrogen pressure, the blue part is Helium. However, when the model ceiling is being violated, the bars change color.

The horizontal black line is the ambient pressure.

When the tissue pressure bars are growing, it means the tissue is on-gassing, which happens at decent and bottom. When the pressure bars are shrinking - at ascent - the tissue is off-gassing.

Below each bar there are lines that represent:

Heat

This panel shows the heat map of tissue compartments, where the color tells is the compartment if on or off gassing and by how much.

The control of the colors is not quite yet what it should be, so this feature needs a little polishing.

Plan

This panel is not yet implemented and is in the backlog of future development. The intention is to print a dive plan here with all the details.