Quote: (Originally Posted by
bletso)
Gill,
It goes to the root of human nature. Most HUD.s, rEVO included, are really secondary displays. Raw info has had decisions made on status etc. When it dispays different pulse rates, colors, etc, these indications are based on internal settings the machine makes, not you. i. e. rEvo assumes that if the PO2 is under .5 for 5 minutes, it shuts down.
Maybe, I am running that PO2. That would be my decision, and as long as it remains where I want it, my business.
I believe that the decision making is the divers responsibility, not a third party. I use two independent primary displays, both of which I can view simutaneously. If I could not view them at the same glance, then by human nature, I would probably start to rely on the one I could access the easiest and by default it would become a primary/secondary display configuration.
HUD's and displays like the rEvo funnel both cells to one controller. I would use the HUD as my primary display (human nature) and rely on the digital screen as a secondary. But, the HUD is being driven by the same circuitry, therefore no isolation between cells. If the controller goes awry, you loose all.
Don't get me wrong, the rEVO looks like a well thought out design and package, but IMO it is hindered by the funnel.
Using a system like the one I put together is two completely independent systems. Even the common case is devided into independent sections. The set points are run by me with real numbers, which translate into real values to my brain as regards PO2.
I have stated before and I might as well say it again, if you give a guy a crutch, he more than likey begin to rely on it. Buzzers, horns and other types of indicators are just such devices. One will dive and rely on the outside system to warn him of impending disaster.
Constat monitoring your PO2 is important to spot certain failure modes. I don't want to wait until the unit is telling me, OH, BTW, you have a problem.
I hope this hasn't been to confusing an expanation.
Dale
This information is totally wrong.
The Sherewater HUD (as an example) has totally independent circuitry and power supply as does the Revo HUD and the Under Water Guardian HUD
On the Shearwater its independently calibrated and shows your PP02 on all three cells all the time.
If my hand set should fail I could carry on the dive on the HUD.
Its not a crutch its a primary display
As for MCCR being easier to fly than ECCR? if you haven't tried one for a while how do you know? Despite all the problems with my ECCR units I have to admit they are much easier to dive with greatly reduced task loading than the MCCR
Today I did a 65m dive for just under three hours run time. I laid the guide line and I had a camera with a large arm and strobe with me to take picks. We found the china room and collected china and then I bagged it up, cut the waster, collected my strobe and clip unclipped the station and dealt with a buddy who had a total unit flood and bailed to OC at 40m. Then I checked the gas sent up the yellow bag and kept a close eye on things and managed the drop tank when it arrived.
All this time I ran the unit manually and I can tell you it was hard work and the PP02 track will NOT look pretty. Had I been on the Inspo the PP02 track would have not altered a jot.
You can tell me your a better diver and would have taken all this in your stride but i have actual printouts of actual dives and I am quite shocked to see the fluctuations in PP02 compared to a ECCR.
Unless you have a similar print out Ill take what you say with a pinch of salt as I too felt I had a far better control of my PP02 than the evidence of the graph showed.
When i got my HUD back in 2004 I took a load of flack on the net about not checking my hand sets and people saying HUDS are pointless / dangerous. I am glad now they are standard kit on Visions Revos and Megs that many more divers see their merit.
ATB
Mark Chase