• Enter depth, time and gas details as legs into the left column, using the Add Level button at the bottom.
• Place a check mark next to the legs to be included into plan.
• Enter deco gases into the deco gas column, using the Add Deco button at the bottom.
• Place a check mark next to the deco gases to be included into plan.
• Set a time interval - either by selecting 24 / 48 hrs, or entering actual time.
• Press the Calc button at top.

• Follow the run times. The displayed stop times include the time required for transit between stops
• Do not add any extra stops in the deep sections of the dive. This will add significantly to the decompression obligations. You may extend the shallow stops without side affects.
• Carry out the ascents at the rates used in the plan. Ascending at a rate faster or slower than specified may require additional decompression.

MultiDeco offers the VPM-B and VPM-B/E models for planning dives. The VPM-B is the current model in wide spread use today. VPM-B/E is an extension made for divers undertaking very deep and long dives. It generates plans with additional shallow time that simulate an overlapped bubble model and a Haldane plan, for time times when maximum safety is required. For most divers, the B and B/E plans are the same, because B/E only begins to deviate after large gas loads (90-100 mins deco required).

The VPM in MultiDeco is a highly tuned deco tool and you must follow the plans closely. Any large deviations from planned ascent in depth & time during decompression, must be avoided. Significant changes will require additional deco time to compensate. This is most relevant with slowed or delayed ascents in the deepest parts of the ascent.

You may add extra time, if required to the last deco stops without side effects.

Plans with deco mixes will generate slightly faster run times for the mid level stops - even before any gas change has occurred. VPM calculates decos in an iterative process, and adjusts for additional off gassing capability later in the deco from the high O2 mixes to come.

If you are forced to adopt a new plan in water from lost / broken deco gas - wait out the additional time between the two plans, at the current level, and then commence timings per the new plan. (see also question 1 in top ten)

A faster deco from deep dives is usually possible when the first deco gas switch is at, or just above, the same level as the first deco stop. High helium deco mixes after trimix dives, usually do not accelerate deco.

All switch depths onto deco gases / mixes, are controlled by the ppO2 settings in configuration. The program will select a gas from the checked items in the deco gas list, based on the max ppO2 settings, for each of the required stops.

Switches in mixes during the dive are controlled by inserting legs into the plan, with a time of zero(-). e.g.

Switch in descent from travel to bottom mix.

25, - , 32 travel gas 32% to 25m.
95, 30, 12/60 30 mins at 95m, on 12/60 mix

Multi level descent with switch

22, 5, 32 5 mins at 22m, 32%
22, - , 18/30 swap to bottom mix when leaving 22m
65, 20, 18/30 20 mins at 65m on mix

Switch in ascent, on a multi level plan.

40, 30, 21 30 mins at 40m, air
21, - , 50 swap to 50% in ascent at 21m
10, 20, 50 20 mins at 10m

The program reads down the list of legs, and creates plans based on the order each leg is encountered. To rearrange the order of legs - drag the selected leg up / down the list (hold down left mouse button), or right click and select Sort List.

The program reads down the list, and creates plans based on the order each leg is encountered. Multi level plans (or cave profiles) are entered by specifying each level (and gas change) in sequence. e.g.

Multi level descent with switch

22, 5, 32 5 mins at 22m, 32%
22, - , 18/30 swap to bottom mix when leaving 22m
65, 20, 18/30 20 mins at 65m on mix

Multi level ascent.

40, 30, 21 30 mins at 40m, air
10, 20, 21 20 mins at 10m, air

Multi level ascent, with gas switches.

55, 25, 18/25 25 mins at 55m, 18/25 mix
21, - , 50 swap to 50% at 21m
10, 20, 50 20 mins at 10m, 50%

Multi level saw tooth dive.

60, 25, 18/30 25 mins at 60m, 18/30 mix
10, 20, 21 20 mins at 10m, swap to air
30, 15, 21 back down to 30m on air
15, 25, 21 up to 15m for 25 mins on air

In all cases above, any gas in the deco column is not utilized until the last dive plan leg has been processed. If a switch to another gas is required in mid water, then insert a leg with a time of zero. See travel gas.

On multi level ascent plans with sufficient change between levels, MultiDeco will insert decompression stops mid water prior to reaching the next level.

The program reads down the list of legs, and creates plans based on the order each leg is encountered. To rearrange the order of legs - drag the selected leg up / down the list (hold down left mouse button), or right click and select Sort List.

Feedback from divers has suggested the following settings should be applied. Nominal is for navy divers and the super fit. Plus 2 or 3 is the normal setting for most divers. Set a plus 3 or 4 with strenuous, cold, a series of multi day dives, extra safety, or a prior history of DCS or symptoms.

Inside the program, the conservatism setting increases the Critical Radii of N2/He in the VPM algorithms. From these base values, by this increase: 1 = 5%, 2 = 12%, 3 = 22%, 4 = 35%, 5 = 50%. The Critical Volume setting is on by default.

This adjustment chooses the threshold of micro-nuclei radius size, that becomes the limiting dimension through the ascent and decompression. This adjustment operates at the core of the VPM algorithm. This setting operates in reverse: a larger radii is a more conservative plan.

You may notice on some dives in VPM, setting the conservatism higher has little apparent effect. This will happen because at some point, decompression is complete no matter how much extra conservatism is added.

Do not fake conservatism in VPM e.g. using Nominal and inflating the depth or time. Doing so will cause the repetitive factor time penalty to be reduced, and subsequent dives plans will have insufficient deco time applied.

Depth Select either Feet or Meters.

RMV's Units for calculating gas consumption's.

Stop Times Set the rounding up factor for all deco stops.

Water Fresh or salt water (SG of 1.026).

Conditions - Deco Steps

• Stop Size deco step spacing.
• Last Stop depth if last stop depth needs to be deeper than normal stop Size spacing. Separate values for OC and CCR.
• Deep Stops Increases step spacing to double sized the step size, or shortens to half the StopTimes value. This applies to the deepest portion of a dives decompression, and only greater than 30m/100ft.

Conditions - Deco mix depths

• Max depth on 100% O2 Sets maximum depth for use of pure O2 deco.
• Max ppO2 for deco mix ....% This value controls when switches are made to deco mixes depending on the O2 content and maximum ppO2 set. Three different ppO2 ranges can be specified.

Conditions - RMV

• Bottom Consumption rate for descent, bottom and climb to first deco stop portions of the dive. Specify in litres/min or cubic ft/ min, at 1 ATA.
• Deco Consumption rate for all deco stops portion of the dive.
• fiO2 adjustments This setting cause the program to adjust the inspired mix by the values supplied. See the SCR rates topic.

Extended Stops

• Add to stop time - this controls if the time specified is a minimum time, or will add extra to the required stop time.
• All deco setting will cause the extended time to occur, even if a stop was not required at that level. On simple dives, when little deco is actually required, this option should be disabled, as it will put a stop in where it is in conflicting with the underlying plan.
• O2 window affect causes to program to check if sufficient deco was carried out during the extended time and to possibly bypass the next stop all together. i.e. if an extended period was used on a 50% switch, then the adjacent 60ft/18m stop might be eliminated. Without this option, all stops from the extended depth onwards will be printed will at least the minimum stop.
• Accelerated Stops This procedure permits the diver to briefly violate the ascent ceiling limitation under normal decompression. It is included to satisfy the "fast helium" concept. The off gassing rate is accelerated due the increased Pss permitted in this period, by this option. It is conditional on the dive using full O2 as a final deco mix.

  Three different mix ranges are available
  up to 28% N2 / 25 to 80% He
  28 to 45% N2 / 25 to 70% He
  50 to 75% N2 / 25 to 50% He

  example: selecting the last item only, planning a dive with a 50/50 O2/He deco mix and 100 O2. This would cause the last two stops on the 50/50 to be accelerated (the 40/30ft 12/9m stops).

CCR Setpoints Set this to match the set point controller / ppO2 readout on your rig. Bar = 1000mb. Atm = 1013.25mb

Conservatism Nominal is the base value, and is for the super fit and divers with a proven track record of fast deco. Plus 2 or 3 is the normal setting for most divers. Set to plus 3 or 4 with strenuous, cold, a series of multi day dives, extra safety, or a prior history of DCS or symptoms.
This setting increases the Critical Radii of N2/He inside the VPM algorithms, from these base values, by this increase: 1 = 5%, 2 = 12%, 3 = 22%, 4 = 35%, 5 = 50%. The Critical Volume setting is on by default.

VPM Model MultiDeco offers VPM-B and VPM-B/E models for planning dives. The VPM-B is the current model in wide spread use today. VPM-B/E is an extension made for divers undertaking very deep and long dives. It generates plans that simulate an overlapped bubble model and a Haldane plan, for time times when maximum safety is required. For most divers, the B and B/E plans are the same, because B/E only begins to deviate after large gas loads (90-100 mins deco required).

Descent Ascent rates Values must cover all dive depths, no overlaps in each range.

Elevation data

• Elevation Dive elevation.
• Hours at dive elevation Time at dive location prior to dive.
• Ascended from Elevation at start of journey to reach dive site.
• Travel Time Time of journey to reach dive site.
• Avg. elevation last 2 weeks Average elevation during last two weeks of surface time.
• Estimate lower for safety.

Air or other Gas breaks can be put in the plan. These changes in inspired mix, are not just inserted, but actually calculated as part of the decompression for the dive.

Conditions Select the conditions that will trigger the breaks to commence.

Timing The Reset will cause the timing intervals to be interrupted each time a new level is started. Leave this unchecked to keep break timings at the intervals specified.

Break gas Select the gas used on breaks. Last Deco mix will break to the gas used as the previous deco mix (if present) or the bottom mix when relevant. Use Special Mix when a unique gas is used for breaks only.

The program will save data to each unique diver name entered. Each diver should save dives to their own name / record. The saved tissue gas loading data is used in all subsequent dives for repetitive calculations (two weeks).

The Guest mode starts with a clean tissue status, but cannot be saved too, or used in Advanced mode.

This will monitor the output for conditions that are selected. Any levels triggered will be highlighted with a background color in the displayed plan. Press the checker panel next to an item, to change a selections color. The following conditions are monitored:

High or low ppO2,
CNS and OTU levels,
Rebreather base mix ppO2 vs depth,
Tank volume vs consumed values,
Isobaric Counter Diffusion levels.

CNS percentages, OTU count, minimum and maximum ppO2 for each segment of the dive. For CCR divers, when the ambient ppO2 of base diluent ppO2 exceeds the setpoint selected.

IBCD (Isobaric counter diffusion) levels. This monitors for changes in the inspired mix when switching to a new deco mix. It will flag a level when the rise in inspired partial pressure of N2/He exceeds the selected amount (default 0.5 ATA). A visual representation of this can be seen in the ppInert graphs display.

The program includes a planning system for complex formula involving gas consumption, depths, times and matching to a second diver. See the new formula panel to see a diagram of variables and settings.

You may create new formula from the array of predefined variables and calculated consumption rates provided. Use the diagrams and Identifiers to create the required formula. A complete list is displayed in the Set test values screen.

Expressions: Predefined variables, integer (signed 32bit), floating point (double precision).

Operators Precedence

* / 1st
+ - 2nd

Use parenthesis () to change operator precedence.

Nested formula not permitted at this time. Recursion not permitted.

Verify the formula for expected output, by initializing the value of test variables in Set test values.

Calculated values for consumption section / segments return value consumed in tank pressure. Values for Depth return ATA absolute. Time values return in minutes. Rates are pressure consumption per minute per ATA (SAC) - in psi or bar.

Any variable specified in a formula but is not used in the dive plan, will return a value of zero (0). Use the error switch to control if this should generate an error, or proceed.

Buddy calculations: The program automatically reverses the Prime and Second diver positions (rates, equipment sizes) - the calculation is run as if the Second diver was the Prime diver, and the result for the Buddy is displayed in this context. i.e. the Second diver consumption rate is corrected to match any difference in supply from different diver tank sizes.

Sample formula:

SimpleThirds: 2/3rds of Primary diver tank pressure.

Pp * 0.66

RockBottom DIR: 2 divers using one system - 2 minutes each extra on bottom, ascend to surface or first deco gas switch, with an increased RMV of 1.5 times for both.

Primary consumption rate per min * depth at last bottom section + consumption on ascent

Secondary consumption rate per min * depth at last bottom section + consumption on ascent

((2 * Pr * Db0 + McP) + (2 * Sr * Db0 + McS)) * 1.5

Rates are predefined as tank pressure drop rate per minute at 1 ATA. Second diver rate is adjusted automatically for Prime diver tank size differences.

This implementation of RockBottom has neglected the 3 * 1 minute safety stops for NDL dives.

CCR planning is much like OC planning, with the addition of a Setpoint. The program calculates the inspired mix from the diluent and current depth. The program assumes instant loop changes with new levels or settings - no slides, no time delays.

When setpoint exceeds natural pp of 100% O2 for given depth, the program assumes an O2 flush. When setpoint is lower than natural pp of diluent, the program assumes that the loop has been breathed down. Legs and changes are entered like so:

Dive with changes in diluent and setpoint

50, 30, 10/40, 1.30 30 mins at 50m, 1.3 setpoint
20, - , 21, 1.40 change to air diluent, and 1.4 at 20m
6, - , 21, 1.60 O2 flush at 6m, 1.6 decreasing to sfc.

Gas or setpoint changes in mid dive

50, 30, 12/40, 1.30 30 mins at 50m, 1.3
50, 10, 12/40, 1.20 change to 1.2 with another 10 mins
40, 10, 16/30, 1.20 10 mins on new diluent at 40m
20, - , 16/30, 1.40 switch to 1.4 in ascent at 20m, continue to sfc.

Multi level ascent dive

60, 30, 12/40, 1.30 30 mins at 60m, 1.3
20, 10, 12/40, 1.20 ascend to 20m, program will insert mid stops
6, - , 21, 1.60 O2 flush at 6m, 1.6 decreasing to sfc.

Bail out SCR for 5 mins, then ascend

60, 30, 12/40, 1.30 30 mins at 60m, 1.3
60, 5, 12/40, SCR 5 mins on diluent only SCR, followed by SCR ascent

The Start Setpoint value is used from surface to the first level or leg encountered in the Diluent & Setpoint list.

For SCR, KISS, RB80, and CCR in SCR mode. Several planning methods offered: Volume Ratio Gas Addition method, adjustment of base inspired mix by factor or literal values.

For VRGA: Enter extraction ratio Ke (RMV / uptake of O2). Enter dump ratio r% - the fresh gas addition component. Sample values can be seen in the panel below.

For factor and literal: Enter values that represent sample points in the depth range of the dive. The fixed setting will keep the adjustment fixed beyond the deep value specified. Separate set of values for Descent, Bottom, and Ascent (all deco is ascent). Adjustment can be applied as a literal adjustment to the mix, or as a factor reduction to the mix. O2 content.

The program will alter the inspired values across the dive.

Switching to OC for bail out can be done two ways. One is to manually enter the mixes as OC deco mixes and construct a plan in this combined CCR / OC manner. The CCR planning also allows for OC legs to be inserted into a CCR plan. Once the program switches to OC mode, it stays this way for the remainder of the dive.

The other bail out method is to use the Bail out planning button. This will allow different deco models and other settings to be changed for the bailout situation.

When planning with a complex multiple segment bottom, or stepped levels, the bail out planning assumes and makes a bail out for the "last" segment only. To plan complex bailout situations, enter new segments manually as OC segments into the left column, and construct failure point this way.

Bailout or regular planning may be performed in SCR mode. Enter dive legs with the SCR option instead of a setpoint. The SCR fiO2 adjustments control the inspired mix for these legs.

Saving a plan updates your tissue loading data. This is where MultiDeco keeps track of tissue gas loadings for repetitive dives. Note that the repeat factor in VPM can be as long as two weeks.

You may plan and re-plan a dive as often as you like, but once the Save button is pressed, the data is committed. There is no Undo function. Please ensure that the saved information is an accurate record of the dive.

The Dive log lists all the saved dives to date. The items are

SI: = surface interval in minutes
Profile: (depth,time,mix),(...)
Deco: mix,mix,...

Each diver has a separate tissue data record and log.

Each time a calculation is performed, that data is saved to file automatically. It overwrites the previously saved one. All data is saved into a set of folders, located in the "My Documents" location. This location depends entirely on your computer and choices and is typically:
(XP) "C\Documents and Settings\\My Documents\MultiDeco\", and (Vista, 7, 8, 10) "C\Users\\Documents\MultiDeco\"

Calc generates

vpln-out.txt same as displayed plan
vpln-sht.txt depth, time, runtime - aligned
vp-short.csv depth, time, runtime - aligned in csv format

Lost Deco generates

vp-lost.csv depth, time, runtime - aligned in csv format

Less or More generates

vp-mrlss.csv depth, time, runtime - aligned in csv format

Each of the csv files can be imported into Excel, and manipulated or formatted further.

Files can be numbered sequentially. Right click the mouse on the main screen, and select Sequential Files. All files will be name separately from AA through to ZZ.

For the PC only, MultiDeco can link dive data directly into the Microsoft Excel program. The data link is via COM and should work with Excel version 97 and onwards. MultiDeco is supplied with a graph template (located in "My Documents\MultiDeco\template" folder).

Note that this is a "live" connection - we compute a plan in MultiDeco, and its data is sent to Excel at the same time.

To start the link into Excel :
Press the green Excel button in the menu bar. Excel should load and be visible next to MultiDeco. Then plan and calculate a dive as normal in MultiDeco. Each time a dive is computed, the data and a graph will be drawn into Excel. This also applies to Lost gas and Alternate (-/+) plans.

If Excel stops responding, then an error has probably occurred. The only sure way to recover from an OLE/COM error is to restart the whole computer. If excel fails always fails to start, try the re-register procedure. In the Run box, type excel /register. Excel relies on several services to be running on the computer - DCOM, RPC.

Options : Located on a context menu in the top menu bar (right click the top menu bar area).

Start up full screen : controls how Excel and MultiDeco are positioned on screen on starting Excel Full screen will place V-Planner to the left, and Excel will occupy the remaining 60% of the screen.
Link to graph sheets: controls the link between V-Planner and control of the visual graph sheets. Pressing the various dive tabs in V-Planner, will cause the focused sheet in Excel to follow, and displays / hides graph sheets to match the dives calculated. With this option off, data and graphs are still drawn in excel, but the focused (active) sheet is not changed.
Add template: adds a template to the list.

Custom templates : You may build your own custom templates for use in this COM link. V-Planner always writes to first WorkSheet in the book (the "Data" sheet in the sample book). That sheet may have any name you choose. The graph sheets are optional. You create links between the data cells and your graph design. See the Excel help and samples for details on this.

In the worksheet :
Columns 1 through 8 - all drawn as general formatting and floating point numbers, except the mix column which is text. This repeats again for each dive, at a column spacing of ten columns.
Columns 9 and 10, ("spare1" and "spare2") and never touched (read, write or cleared). These columns are for your own custom formula.

If the Link to Graphs option is selected, then V-Planner will:

Adjust Y axis Major, Minor, and Title values per metric/imperial systems.
Adjust X axis Major, Minor, Maximum values to bring time scale into line.
Shift Active sheet to match current tab selection in V-Planner.

If Link to Graphs is not selected, then V-Planner will just fill the "Data" page. This allows you to create your own graph design using Excel cell links.

If Excel stops responding, then an error has probably occurred. The only sure way to recover from an OLE/COM error is to restart the whole computer. If excel fails always fails to start, try the re-register procedure. In the Run box, type "excel /register"

Varying Permeability Model (VPM) References

Information on the VPM model and how it works can be found here.

http://www.decompression.org/maiken/VPM/VPM_Program_Site_Map.htm

MultiDeco offers VPM-B and VPM-B/E models for planning dives. The VPM-B is the current model in wide spread use today. VPM-B/E is an extension made for divers undertaking very deep and long dives. It generates plans that have more shallow time and emulate an overlapped bubble model and a Haldane plan, for time times when maximum safety is required. For most divers, the B and B/E plans are the same, because B/E only begins to deviate after large gas loads (90-100 mins deco required).

VPM-B/FBO is a variation for bail out. It speeds up the deep ascent to help reduce OC gas volumes.

Additional articles of VPM design:
vpm_deco_reinders.pdf
vpm_expl_corado.pdf

VPM is experimental. There is no database of proven dives, or scientific results to look over. However, there is a database of un-proven dives of 100,000 + records. These records come from direct uploads of the Liquivision X1 dive computer. The database is at: http://database.hhssoftware.com/

Note that VPM is a highly tuned deco model and it requires disciplined control of depth and time during decompression.

If you're getting started and unsure about VPM, try planning with conservatism of +4 and padding out the last two or three stops to look like any M-Value deco model. Over several dives work your way closer to a +3 or +2 setting, and follow the plans.

The history of VPM model is summarized at: VPM model history

The programs have a 30 day trial for Air and EAN dive planning. Trimix dives require a registration.

If you wish to see a sample of a trimix plan, please email support and ask for a sample.

On the PC / Mac: A registration allows for the issue of 4 keys a year.
On an Android: A registration allows for the issue of 2 keys a year.

This should allow for extra computers and replacement computers in the future.

Every device has a unique install code and requires a key. Install codes cannot be transferred or changed. Instead, you create a new key for each new code at: new keys

Each computer and each logged on user, will need a unique key.

Registration groups:

The registration is divided into groups, and each group shown below requires its own registration purchase and fee.

• Desktop - PC, Mac, Linux, (4 keys per year)
• Mobiles - Android, MS Mobile, (2 keys per year)
• iPhone, iPod, iPad (via Appstore only)
• X1 programs (obsolete).
• DR5 programs (obsolete).

All registrations are valid for life.

Existing customers can reissue / resend keys from:

Lost keys

Email address can be changed online at:

Change email

Note that you will need to be able to respond to a confirmation on the old address to activate the new address. If the old address is now dead, then contact support and request the change.