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NERD2 Monitor questions

Discussion in 'Shearwater Research' started by stuartv, Jan 20, 2019.

  1. stuartv

    stuartv Seeking the Light

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    I just read this article:

    What is DiveCAN® and why should I care? - Shearwater Research

    It says:

    I want to put a NERD2 Monitor on my rEvo (which has a Predator DiveCAN controller w/rMS).

    - The NERD2 Monitor cable that rEvo has appears to be a 4-pin DiveCAN connector on one end and 3 individual Molex connectors on the other end, which connect directly to individual O2 sensors. I thought the NERD2 Monitor was supposed to be digital. How can it be digital if its only input is the analog signals from the individual O2 sensors?

    - rEvo sells a NERD2 Monitor for $2500 or so. Dive Gear Express sells NERD2 Monitors for $1750. If you order from DGX, you have to choose from JJ, O2ptima, or Prism2. But, the Shearwater article says those 3 and the rEvo are all interchangeable. So, what's the difference between them?

    - if you order from DGX, why do you have to choose between those 3 instead of just having 1 choice that will work with any of those 3?

    - will any of those 3 from DGX work with a rEvo?

    - if one of them will work with a rEvo, does that mean it will work by connecting to the rEvo 4-pin cable that has 3 Molex connectors on the other end?

    - I have a Shearwater Pursuit HUD on my rEvo now. Is it possible that the NERD2 Monitor would connect to the existing cable for the Pursuit?

    I also have a Predator EXT on my rEvo. I am really just trying to figure out the most cost effective way to ditch the Predator EXT and the Pursuit HUD and have a NERD2 as my monitor - and without using a Fischer cable.

    What would be really nice is a cable that goes from the O2 sensors to a black box like the Pursuit HUD has, and then a wireless feed of the O2 data from the black box to a NERD3 Monitor. I.e. a wireless DiveCAN Monitor bus. That would sure make it a lot nicer and easier to also use the same NERD3 when diving OC.

    Thanks for any information you can provide!
     
  2. stuartv

    stuartv Seeking the Light

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    Location: Manassas, VA
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    @tbone1004 You told me before that the DiveCAN NERD monitor is interchangeable between the rEvo, JJ, and others. I just feel like I'm having a disconnect somewhere since I thought DiveCAN is supposed to be digital and I don't see how the 4-pin cable for the rEvo can possibly be feeding a digital signal to the NERD.

    Is the rEvo cable I'm looking at analog and it only works with a rEvo-specific NERD2 that is not actually DiveCAN? It just uses the same connector on the cable, but it's actually analog?

    Is there some other rEvo kit that would be required that would actually provide a DiveCAN Monitor Bus feed out to a DiveCAN NERD2?

    Is the rEvo DiveCAN Monitor Bus something that was planned but never actually came to fruition?
     
  3. runsongas

    runsongas Loggerhead Turtle

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  4. stuartv

    stuartv Seeking the Light

    # of Dives: 200 - 499
    Location: Manassas, VA
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    So, you are saying the NERD2 DiveCAN Monitor has an A-2-D converter inside the NERD itself?

    I considered that possibility. But, that would mean that all that talk about certain CCR manufacturers having a DiveCAN Monitor bus would be, ummm, baloney? You're saying the entire DiveCAN Monitor bus is self-contained inside the NERD2?

    If that's how it is, then as long as you have a way to route the cable* from outside the CCR to inside, to connect to the O2 sensors, and keep that end dry, you could use a NERD2 DiveCAN Monitor on any CCR. That makes no sense (in light of the Shearwater info that identifies specific brands that support it and the DGX page that only sells them for 3 kinds of CCRs).

    * the one that is 4-pin DiveCAN on one end and molex connecters (or, as appropriate for the specific sensors on whatever CCR you're using) on the other end
     
  5. runsongas

    runsongas Loggerhead Turtle

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    the divecan electronics are on the ccr head unit, not in the nerd. the fischer version is different because the ADC is in the module on the cable.

    different manufacturers may have slightly different software on their heads, which is why the nerd isn't generic.
     
  6. stuartv

    stuartv Seeking the Light

    # of Dives: 200 - 499
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    What I am talking about is this:

    https://www.oceanedgeoutfitters.com/Shearwater-NERD-2-4-Pin-Deco-Computer-p/revo-r424.htm

    I was told that the 4-pin cable, like this has, is the connection for a DiveCAN monitor. That is as opposed to a 5-pin connection for a controller.

    So, the one I linked has the 4-pin connection, but it does not actually SAY DiveCAN. So, since this kit does not involve the rEvo "head" at all, I guess it is not DiveCAN.

    The Shearwater article I linked mentions rEvo in its list of units that can interchange DiveCAN monitors. So, how do I get a DiveCAN Monitor bus connection on my rEvo so that I can attach a NERD2 DiveCAN Monitor? I mean, right now, it does not have any extra cables that are not attached to anything... The cables that run into the O2 sensor tray are 3 - one for the controller/head, one for the HUD, and one for the Fischer cable Predator. To have a DiveCAN monitor going to the "head" (really, a black box on the side), it would need another cable (or a cable with 5 connectors, so it could attach to all 5 sensors).
     
  7. stuartv

    stuartv Seeking the Light

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    Location: Manassas, VA
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    ps. The Shearwater article specifically says that for Monitor Bus devices, the ones mentioned are interchangeable. No, for Controller Bus, but yes for Monitor Bus.
     
  8. runsongas

    runsongas Loggerhead Turtle

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    you have to replace the hud with the nerd unless if you hard wire a fischer connection and get the fischer nerd.
     
  9. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

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    @stuartv the Revo monitor you linked is NOT a DiveCAN NERD. It is an analog nerd that happens to have a DiveCAN style cable instead of a fischer *different pin count though*.

    You would have to have an OBOE board inside the head somewhere to send out the monitor signal. Your pursuit HUD is likely set up as analog and is completely independent from the DiveCAN running the solenoid. There are ways to do it, but you'd have to get Revo to upgrade it and good luck with that. Your best bet is the NERD from ocean edge to replace your current HUD. If you want to use it on OC, you can unplug the wetconnect pins, put the cap on and use it on OC with no issues, same as a fischer. You'd have a cable to tie to the reg hose, but oh well.

    I'm 100% with you on wireless monitors for non-controller devices though. Something tells me @Shearwater is working on that, though we'll see how the luddites in this industry react to it
     
    stuartv likes this.
  10. broncobowsher

    broncobowsher Solo Diver

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    I have a bunch of this stuff. 5-pin is divecan. 4-pin is only monitor (3 cells + common ground)
    The two are NOT interchangeable.
    If you want a controller, you get the divecan with 5-pins. It will talk with the solenoid/cell board in the rebreather.
    If you want a monitor, get the 4-pin. Doesn't have anything to do with divecan. It shouldn't. If the divecan takes a giant dump on you the monitor will still work. Not a single wire is connected between the two.

    I run a Petral controller and a NERD monitor. There is no way the NERD can control anything. It physically won't connect. Mentally it doesn't have the software (which is in the firmware, which is different then the user updatable software).

    It wasn't clear to me at first either. I was hoping the NERD could be used as a backup controller if need be. It can't. I have spent over an hour on the phone over various different calls, and even talked with the same in person at DEMA to really understand this.

    Now brand specific versions, I have no idea how interchangeable that stuff is. I have only played with the revo versions.
     

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