forum.heinrichsweikamp.com

I am a very happy user of a 2N (no. 3050) having done 35 dives with it so far. I have been using a VR3 and as I get older I find the display of the OSTC much easier to read under all conditions. I especially like the way the owner can tailor the saturation/desaturation process so easily and with great clarity, once the theory of tissue compartments and gradient factors are understood.

I have several questions regarding the various custom functions and their values/units.

1. I am confused as to the difference in the effect of CF00 and CF06. It appears that they both attempt to achieve the same purpose but CF00 uses a pressure interpreted as a depth (metres) and CF06 uses a pressure in mbar. Surely, after jumping in the water and descending the OSTC will switch from sleep mode to dive mode through the shallowest (lowest pressure) of the two CF00 and CF06? Does this mean that one of these is redundant?

2. The next question is regarding CF14 and CF45. Both CFs relate to the change in status of the level of GF during a dive, since once the dive is over and you are back on the boat or beach/shore you are outgassing. If they don't refer to the same change of GF how are they different? If they both refer to the same change is one of them redundant?

3. Would it not be easier to understand and set if the units of CF43 (DepthWarn) was in metres rather than mbar? I know that once set it is probably never changed and possibly few OSTC users ever think about setting a depth warning but since it is there I feel that if the units used by CF43 were metres it would be easier to use.

Thank you in advance for clarifying these points and for producing such a competent dive computer.

Cheers
Laurie

Laurie have you read this?
OSTC Custom functions

You should find at least some clarification there.

Thanks for the link Hansjoerg, but that link is the source of my confusion. Let me quote from the Custom Functions manual:

CF00 says:
This value sets the threshold for the
OSTC to turn on and switch into the
divemode automatically. The current
pressure is permanently compared with
the airpressure measured 30min ago.

CF06 says:
The value sets the absolute pressure
where the OSTC activates itself when
submerged. The displayed depth is com-
pensated with the airpressure measu-
red 30min ago.

My interpretation of these two CFs is that they cause the OSTC to turn on when it is immersed in a certain depth of water. CF00 interprets the depth in metres and CF06 in mbar. Both respond to the increased ambient pressure to switch the OSTC on. Do we really need both?

CF14 says:
This value sets the threshold (in percent)
for the gradient factor optical alarm.
Example: CF14=100 - When reaching
a gradient factor of 100% an optical
alarm is displayed.

CF45 says:
GF output is color coded if GF reading is
bigger then this value.
Example: CF45=101% - If the GF is big-
ger then 101%, the output will be co-
lored with Color# Warnings (Default:
Red)

My interpretation of these two CFs is that they both change the colour of the gradient factor display to the warning colour (since that's the only way an optical alarm can be generated). It may be that gradient factors are not displayed until the warning is issued but they both seem to be doing the same thing.

I have also noticed that the Altimeter can also be enabled through the menu path Menu>More>Altimeter>Enabled. If there is a shortage of custom function slots in a future release of the OSTC software I guess that CF49 could be reallocated as well as one each of the two pairs identified above.

Cheers
Laurie

I'm at work so I don't have my OSTC with me but from memory,

CF14 will let you choose when you want to see GF. Example you might want to see it at 20% so it will be displayed when the GF reaches 20%. This will be shown in white (the "normal" color)

CF45 will show you the GF in red (if that's the warning color you chose).

So you have 2 options : white color (CF14) to have the info, Warning color (CF45) to display that something is "wrong" or that you are outside the safety margin you set up.

It works exactly like the PPO2. It will we displayed in normal or warning color depending on how you set it up.

I hope that helps

Thanks Jean-Francois,

That clears up the confusion about the way that CF14 and CF45 work completely.

Are you able to clarify the difference between CF00 and CF06 as clearly too?

Laurie (OSTC Mk2N 3050 s/w V2.20)

Laurie_the_Knot Wrote:
-------------------------------------------------------
> Are you able to clarify the difference between
> CF00 and CF06 as clearly too?

I'm afraid I can't. Maybe it has to do with altitude or something.

Not 100% certain. But yes it has something to do with high altitude and flying.
CF06 and 07

Believe me there are no redundant CF's.

CF00: Depth in which the OSTC will enter divemode when it's switched on
CF06: Pressure which will wake-up the OSTC when it's in sleep mode

regards,
Matthias

heinrichsweikamp Wrote:
-------------------------------------------------------
> CF00: Depth in which the OSTC will enter divemode
> when it's switched on
> CF06: Pressure which will wake-up the OSTC when
> it's in sleep mode



CF00 = 1.0m
CF06 = 1160mbar

When i take my OSTC out of the box and jump into the water it will turn on an switch to divemode at 1.60m depth? But if i turn on the OSTC by hand just before the dive it will switch to divemode at 1.0m?

Why don't you merge this two CF to only one?

I've just read the Custom Functions handbook again and am now confused again regarding the custom functions that affect the display of gradient factors. The Custom Functions handbook shows the following:-

CF08: threshold in % for display of the gradient factor for decompression calculation.
This value sets the threshold for the display of the gradient factor. When reaching this value, the OSTC displays the gradient factor during Divemode.
Example: CF08=20 - When the gradient factor reaches 20 or more percent the value is displayed during the Divemode.

CF14: threshold in % for optical gradient factor alarm.
This value sets the threshold (in percent) for the gradient factor optical alarm.
Example: CF14=100 - When reaching a gradient factor of 100% an optical alarm is displayed.

CF45: GF warning ( color change) GF output is color coded if GF reading is bigger then this value.
Example: CF45=101% - If the GF is bigger then 101%, the output will be colored with Color# Warnings (Default: Red).

I've done some tests in the simulator and found that the GF display is activated using CF08 and its colour changed to warning using CF45. The value of CF14 doesn't seem to make any difference so what is the purpose of CF14?

Laurie (OSTC Mk2N 3050)

CF14 sets the threshold for GF warnings that are stored into the logbook and profile memory. The "optical alarm" in the manual was the red LED in the OSTC1. Now CF45 is the value for the underwater alarm.

regards,
Matthias

Thanks, Matthias, for adding that extra information, however I'm still confused.

I've checked the interface spec for the OSTC and OSTC Mk.2/2N dated 01/12/08 (Last update 11/15/11).

I can find no reference to recording GF alarms in the dive profile except for the Sampling Divisor Gradient Factor (dive header byte 39 and CF23) which I presume will record the gradient factor at the frequency defined by CF23 irrespective of its value.

The event byte uses 4 bits to log 7 alarms, none of which refer to the gradient factor, and 3 other one bit flags for gas mix updates.

Have I missed it somewhere?

Hi,

It's alarm #2: Deco Stop missed/GF violated

I just updated the docu.


regards,
Matthias

Thanks for the update Matthias.

Hopefully I will never be in such a situation where I'm pushing my ceiling to cause this alarm to be logged but will it be logged when the OSTC rises above the deco stop for too long or when the GF exceeds that set in CF45 where the GF display will also change to the warning colour or is it that set in CF14 or is it when the GF exceeds the dynamic GF limit as defined by Erik Baker's algorithm?

Hallo zusammen, hätte da mal eine generelle Frage zum CF14. Mein MK2 ist mit GF-Low 15% und GF-High 60% eingestellt. Ausgetaucht wird noch Vorgabe des MK2. An der Oberfläsche zeigt er dann z.B. GF85% an. Bedeute dass, das ich zu 85% an meinem eingestellten GF dran bin oder am Bühlmann?
Danke für eure Rückmeldung

MK2 #1335

Bist Du sicher das Du da nicht irgendwelche Zahlen verwechselst? Einen GF von 85% solltest Du bei GF High von 60% nie erreichen wenn Du Dich an die angezeigte Deko hältst. Evtl. meinst Du ja die Sättigung die zwischen den Sättigungsdiagrammen angezeigt wird!? Das hat nichts mit dem GF zu tun, zumindest kannst Du das daraus nicht direkt ableiten.

Davon abgesehen ist ein GF high von 60% sehr, sehr, sehr konservativ, da kommst Du ja nie aus dem Wasser. Ich tauche immer 95%...

HTH,
der Jan