KISS Classic with VR3, URM & Shearwater - True redundancy

sunkmail

I currently have the VR3 and URM set-up on my KISS. It works great; Love the HUD!

I just recently (read: yesterday) finished my CCR Training, and while doing this, I had a revelation - Could an integrated Shearwater plug into the 'back-up' PO2 display connector on the URM?

I discussed the idea with the US Distributor of Shearwater (Thanks Curt), and he checked with Bruce. As far as we can tell, there should be no problem. I have ordered a Shearwater and expect it early in the new year.

Here is why I decided to do this:

- The URM needs a VR3 to run the HUD (the software is in the VR3)
- The 'back up' display (usually) connects directly to the pendant
- The pendant could be connected directly to the PO2 Fischer connector

So, the Fischer connector output for the pendant is exactly the same as the output from the kidney Fischer connector.

If I attach the Pursuit up using a double ended fischer (Which has been done directly to the kidney without a URM) to the URM, I will have real-time deco on both computers!

If the sensors go, I will have to take the computers into offline mode, or if one computer fails, I can use the other to finish the dive safely.

I know the VR3 has a different deco algorithm than the shearwater, but I don't think that will be too big of a deal. Also, if the VR3 fails, I'll lose the HUD, but that shouldn't be that hard to live without :P

I hope this all made sense - I'm looking for thoughs and opinions on this set-up. So far, I can't find any real flaw.

Scott

EDIT
------------
I wanted to make one more thing clear, since I didn't explicitly say ...

Both computers will be able to use all 3 cells at the same time.


Once I get this system up and running, I'll let everyone know how well it works

Andy Del

Hi Scott

Um, yes it does make sense, in an expensive soprt of way.

I'm in the process of doing a similar thing on my CK, using a subsea head, display, HUD and a Shearwater Pursuit. Not full redundant computers, but a redundant display for all 3 cells, live deco info if I want, plus another display and a HUD to keep me informed as I dive along.

I suspect your setup has a few common points where a full failure to occur, such as the URM box and cables leading to it, etc. What I'm doing also has a common failure point, the fully potted head. I'm splitting hairs, however I suspect this is a little more robust a setup than using the URM and its various cables. (Did I mention my phobia of octopii? )

In any case, it's quite a few evolutionary steps along from the original 1ATA displays!

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caveseeker7

Hi Scott,

if I'm understanding you correctly the main goal of yours is to have two separate, independent triple cell-integrated deco computers, correct? Hammerhead.

The Shearwater Pursuit, when combined with the Shearwater HUD, gives you two independent pO2 monitors, one of which shows deco.

The URM comes with HUD that shows status and deco info, the VR3 runs it all, and the separate pendent display (the pendent is the display, not the connector block ) provides backup pO2 monitoring.

You want to combine the two ... ... very expensive proposition.

Aside from money, I would consider it inconvenient to have different deco computers. The Shearwater is a bit more up to date in regards to both the software (choice of GF) and the hardware (buttons), with the exception of the yet more expensive VR3 color screen. You'll need to work two different computer systems, menu layouts etc. ... do they run on the same batteries or will you have to take along different ones?

While using different hard- and software does give some additional safety (the same error/problem is highly unlike to occur in both systems at the same time) they always share cells, and in this setup also share the connector block.

And they aren't tested together. Will damage to any cable influence the readings on both computers, will it allow stray voltage from the battery to influence sensor readings and thus your setpoint and deco?

Is it really worth the effort of fiddling it all together?

The URM has some nice features, deco on the HUD, color screen ... and some downsides, solid green for setpoint okay for example. I would check with DeltaP if a second VR3 could be added in lieu of the pendent pO2 monitor.

Before that I would try to talk Bruce into hooking up a second Shearwater Pursuit.

I would also seriously consider Juergensen Marine's Hammerhead, either two secondaries with deco, one with HUD/DIVA, if you're hellbound to keep it without solenoid. Or just get the complete Hammerhead with a solenoid, and add it to your mCCR. Gives two pO2 displays, both with deco, a HUD with DIVA, as well as dual automatic O2 addition. The HUD gives you the choice of pO2 via Smithers code (as used on the Shearwater) or simple green=good, else check your displays (as used on the URM). You can still run your unit manually and have the setpoint controller as backup/safety net. Have a look at the Brett Hemphill video in the DEMA library, you can even mount two onboard O2 tanks. One compensated for the solenoid, one uncompensated for the KISS valve, for more redundancy and deeper dives. Plug in diluent from your bailout gases.

Just some thoughts ... for my diving either Pursuit or URM would suffice.
I would want either with HUD and redundancy, and just use a second non-integrated computer as a backup. Or get the Hammerhead ... .

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Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"

sunkmail

The URM solid Green setpoint actually has a little flicker every second or so. My background is in Electronics, and I think (OPINION, not based on any actual data) that it is a sideeffect of the read/update subroutine, so it is like the hearbeat on the shearwater. Personally, I like the green = good display. It works for me. With that being said, I still check my actual PO2 displays often.

I have no interest in making my unit an eCCR. Just an opinion, and you're welcome to disagree, but I much prefer the manual.

My general thought process is that if I'm going to get a system with 2 computers, I might as well have them both online

Also since I already have a VR3 and URM, the extra cost is only the second computer. Switching to a totally new system (Hammerhead, or the shearwater HUD) wouldn't be economicly feasable.

caveseeker7

Ahhh, we're getting closer.

I like both eCCRs and mCCRs as long as they're well thought out.
MK15.5 and PRISM (,probably the new Hammerhead CCR), or Jetsam and rEvo.
Am just not so fond of the displays on the latter two.

Where I differ from many is that I like to use the setpoint controller when I have one, only running it manually for drills or maintain it a higher setpoint manually at the end of the dive. Just me, then again I usually don't push start my car or slow it with the parking brake just because I might have to when either system fails.

So I do understand your desire to change those. Cool about the flicker on the URM, as long as it shows the read/update routine is still running it works for me.

Have you tried DeltaP about a second VR3 in lieu of the pendent display? Either way, don't let me keep you from adding a Pursuit, would like to get your feedback on everything from installation to use of that setup. Complete with pictures of it all, properly focused and exposed if you would.

Might as well get some milage out of it.

Godspeed!

__________________
Cheers
Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"

onetime

Uh oh, you do realize that saying such a thing is like saying Candyman in the mirror 3x? paulraymaekers will be here in 3, 2, 1....

caveseeker7

I doubt it, Paul knows you can't please everyone all the time.
The rEvodream has merit, 2 separate displays for 3 or 4 cells, and a HUD each.
I just happen to prefer something else. Might well not be the better solution.
The rEvos and rEvodreams have been enormously successful, and rightfully so.

As for the Jetsam displays, I basically like them and the layout.
Digits could be a bit larger, but battery compartment/change needs improvement IMHO.

That's all, just my opinion, no more, no less. Am sure Kim and Paul will endure.

__________________
Cheers
Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"

sunkmail

Alrighty!

I just received my Shearwater Pursuit - The story so far:

Along with the Shearwater, I had to order a double-ended Fischer cable to connect the URM box to the shearwater.

After setting the shearwater to CC, and attaching the cable to the Pendant output from the URM, I turned the computer on, and Tada! all three cells were reading air properly.

(I haven't done a full calibration yet, but they read from .20 - .21 straight out of the box)

I'm not sure when I'll be able to get out on my next dive, but once I test the set-up, i'll write more.

VR3 and Shearwater working together - Who would have thought possible :P

lizardland

Crikey... wouldn't you be better off selling the VR£ parts, buying the Shearwater HUD which, with your pursuit, will give you two independant displays? And a hell of a lot less parts and a much simpler rig. It all sounds a bit complicated.

Cheers,

Stuart

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sunkmail

Well, If I were to sell the VR3, I'd be taking a hit on the price, which Seems a strange thing to do as it works fine. Also, it's only 3 pieces, and one cable. I only have 1 connector on the Kidney, which I can still use with the pendant, if needed.

If I were to go with the Shearwater only system, I'd have to buy a different kidney.

I like this approach. all the extra cable length is nicely coiled between my wing and CL case, and it keeps the top of the unit free from excess things sticking up.

I respect Bruce, and his products, but I do like the true redundancy or running 2 systems. Since different software is computing all information, if there is an un-documented feature (bug) chances are incredably low that both systems would have the same problem.