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Thread: Sentenil VS JJ ccr

  1. #41
    RBW Member Hk101gr is on a distinguished road Hk101gr is on a distinguished road Hk101gr's Avatar
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by ChrisBrown  View Original Post
    The manual control was an example of how po2 variance can affect deco on a deep dive. OK then, machine A maintains an average of 1.2, unit B maintains an average nearer to 1.3. That would be big enough to warrant consideration at 100m.

    Again - the position of the solenoid does not affect PO2 control as much as the solenoids ability to inject oxygen. The vision has a lot of control on the solenoid, which was my original point.

    Not a huge issue agreed. Im just countering the claim about the Shearwater somehow being considered 'better' at po2 management
    Both averages have to be at 1.2 if that is selected. If the average is different then the controller deviates which renders all this discussion meaningless and the controller faulty or a poor design.

    Let's look at it in another way.The meg has specific solenoid firing times and specific idle intervals between those firing times to allow the o2 to mix and get to the cells. The inspo doesn't need this because it injects right next to the cells. So it will fire smaller amounts of gas more often and keep control tighter. Very little to do with large opening times.

    I don't know how the sw operates in this aspect, I guess since so many people are using it and are pleased with its ok, but unless someone shows po2 graphs we can't know for sure. Why would anyone care I don't know either.
    The best controller is one that works more often than all the others isn't it?

  2. #42
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    Re: Sentenil VS JJ ccr

    If the solenoid is next to the cells the cells will be reading the gas as it is mixed with the incoming O2. The result is that it will be reading higher than the true mix of all the gas in the loop.

    If the solenoid is further away from the cells then the gas will have a better chance of being mixed before it is read by the cells, but there will be a time delay.

    No system is perfect. But allowance can be made in the software algorithms to help compensate.

    Im not convinced that 2 divers who run the same set point and same deco algorithms on the same dive would end up with substantially different deco times based on the position of their solenoids and cells and different firing techniques.

  3. #43
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    Sentenil VS JJ ccr

    Quote Originally Posted by Hk101gr  View Original Post
    Both averages have to be at 1.2 if that is selected. If the average is different then the controller deviates which renders all this discussion meaningless and the controller faulty or a poor design.

    Let's look at it in another way.The meg has specific solenoid firing times and specific idle intervals between those firing times to allow the o2 to mix and get to the cells. The inspo doesn't need this because it injects right next to the cells. So it will fire smaller amounts of gas more often and keep control tighter. Very little to do with large opening times.

    I don't know how the sw operates in this aspect, I guess since so many people are using it and are pleased with its ok, but unless someone shows po2 graphs we can't know for sure. Why would anyone care I don't know either.
    The best controller is one that works more often than all the others isn't it?
    Some great points and discussions here but I still think you are misunderstanding my point. I'm not talking about holding the po2 within a tight band. I'm talking more about the machines ability to maintain set point in a dynamic environment such as a seesaw or an ascent. Or with the diver firing adv, flushing etc. if the controller has more firing options, it can deal with it more quickly and with more accuracy. Over the course if the dive, this can result in average po2 closer to set point.



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  4. #44
    So many CCR So little etc Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase's Avatar
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by ChrisBrown  View Original Post
    Some great points and discussions here but I still think you are misunderstanding my point. I'm not talking about holding the po2 within a tight band. I'm talking more about the machines ability to maintain set point in a dynamic environment such as a seesaw or an ascent. Or with the diver firing adv, flushing etc. if the controller has more firing options, it can deal with it more quickly and with more accuracy. Over the course if the dive, this can result in average po2 closer to set point.



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    Realy?

    Personaly I find this fixation with holding set point to within 0.00 something a little odd. Its just not that important.

    But for the sake of discussion.

    Hears a 3 hour dive to 95m on a Shearwater. (note from 9m and up I run it manualy)

    Can we see a PP02 profile for a Vision for a simila dive?


  5. #45
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    Re: Sentenil VS JJ ccr

    Back to original poster:

    I have both - my first CCR was Sentinel and then I switched to JJ.

    The JJ is has great features and works as the whole unit. The Sentinel has great features but somehow the sum of it makes an awkward unit and one tends to wrestle with it (it doesn't stand up without a mod stand, to open scrubber you need to lie it down and strip unit which is not great on a boat, bulky, heavy, unreliable).
    I respect VR and the Boris seems a classic part of CCR history (maybe I should have gone for a Boris) but the Sentinel never worked well for me, even though I wished it did.

    The JJ is fantastic and a dream to dive. Reliable, sturdy, and much more streamlined and smooth in the water. Great fun to dive and does exactly what it is supposed to do. I modded mine with a Golem Shrimp and HUD holder and will probably add a MAV and some shut-offs.

    The JJ I customise and MOD to personalise it. The Sentinel I modded to make it work (added a stand which added even more weight, tried the travel kit to make it less bulky etc but never really made it enjoyable for me).

    Sounds like you favour the Sentinel from your questioning and are looking for posts to support that. Check the forum though. You find a lot of posts on issues with the Sentinel, very few on issues with the JJ.

    Good luck.

  6. #46
    Mostly cold ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown's Avatar
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    Re: Sentenil VS JJ ccr

    for anyone interested in whats happening with VR

    http://www.rubbernews.com/article/20...reather-market

    Avon Protection’s strong entrance into military dive market


    Mark - I posted at least twice that I don't thinks its a huge deal. Im simply counteracting DwaneJ who mentioned something about the superiority of the shearwater po2 control. I also pointed out that an average po2 on 1.2 versus 1.3 would yield up to 30 minutes less deco.


    Hopefully this will ultimately be a good move, especially if AR see the civilian development / market as worthwhile. We are all used to being beta testers aren't we? LOL

  7. #47
    So many CCR So little etc Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase's Avatar
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by ChrisBrown  View Original Post
    for anyone interested in whats happening with VR

    http://www.rubbernews.com/article/20...reather-market

    Avon Protection’s strong entrance into military dive market


    Mark - I posted at least twice that I don't thinks its a huge deal. Im simply counteracting DwaneJ who mentioned something about the superiority of the shearwater po2 control. I also pointed out that an average po2 on 1.2 versus 1.3 would yield up to 30 minutes less deco.


    Hopefully this will ultimately be a good move, especially if AR see the civilian development / market as worthwhile. We are all used to being beta testers aren't we? LOL

    Seriously Chris I have never noticed this diving with Vision buddies even when I dived MCCR?

    I dont know the ins and outs of Shearwater injection system but i know it dosent drop the ball down to an average 1.2 on a 1.3 set point on a 3 hour dive?

    I have hundreds of PP02 printouts in my old shearwater logs that show that

    ATB

    Mark

  8. #48
    Mostly cold ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown has a reputation beyond repute ChrisBrown's Avatar
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by Mark Chase  View Original Post
    Seriously Chris I have never noticed this diving with Vision buddies even when I dived MCCR?

    I dont know the ins and outs of Shearwater injection system but i know it dosent drop the ball down to an average 1.2 on a 1.3 set point on a 3 hour dive?

    I have hundreds of PP02 printouts in my old shearwater logs that show that

    ATB

    Mark
    I didn't say it drops the ball. Plus, how would you know as you manually maintain PO2? Thats why we can't compare. We would need to do a dozen or so ascents on the same wreck with the electronics ONLY controlling set point. No pump pumpy o2 finger :)

  9. #49
    So many CCR So little etc Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase's Avatar
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by ChrisBrown  View Original Post
    I didn't say it drops the ball. Plus, how would you know as you manually maintain PO2? Thats why we can't compare. We would need to do a dozen or so ascents on the same wreck with the electronics ONLY controlling set point. No pump pumpy o2 finger :)

    No I only switch to manual at 9m and thats AFTER getting to 9m

    So the only PP02 drop ascent the unit is missing is the one from 9m to 6m

    all the big ascent bit is on ECCR

    Sorry if that wasnt clear

    We all drop to low set point after 6m dont we?

    ATB

    Mark

  10. #50
    RBW Member Mr B. is an unknown quantity at this point Mr B.'s Avatar
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    Re: Sentenil VS JJ ccr

    Quote Originally Posted by subbaltica  View Original Post
    I dived both Sentinel and JJ. For my type of dives (wreck, and open water, cold waters!) definitely Sentinel. I love HUD options that tells you all Ya need to know in simplicity (not counting blinks) Sentinel is much more open for Diver. You can configure almost anything to your purpose. Jest it is bigger but it has the best scrubber to dive time ratio. Lets face it aluminum build is not for cold water. Also i do not like the idea of BMCL out in the open without me seeing it. In Sentinel CL is protected by hard cover.
    JJ has no additional PO2 control (primary+HUD)
    Sentinel has primary, secondary and HUD (HUD shows Deco !)
    JJ uses external batteries - Sentinel internal triple redundancy
    JJ has no BOV it comes as standard for sentinel
    Sentinel has Electronics designed for this CCR - JJ uses OEM
    Sentinal has capability to monitor Your CO2 level
    Sentinel has TPM in standart it tells You how and if Your sorb is working

    The only big question about Sentinel is what is going to happen to the company. Their support is still working and it is well above average but will it continue like that ? I spoke to Kev at BalticTech Conference and he assured me that teh Product will not die...but we will see. So if you belive it take your chance and buy Sentinel Expedition for great prica that those are available now.
    +1, I agree 100%. But JJ is also for cold water and is more flexible with tanks... Well both are good units, no question
    Last edited by Mr B.; 4th February 2014 at 11:26.

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