Thread: The SDI issues

Reply to Thread
Page 17 of 21 FirstFirst ... 7131415161718192021 LastLast
Results 161 to 170 of 208
  1. #161  
    Quote Originally Posted by Blair S. Paulsen View Post
    FWIW, Jarred has never been a fan of P-tap for on camera power distro. No way to know what percentage of issues noted in this thread are directly tied to the inherent limitations of an unshielded connector that will presumably hit the positive + pol before the negative - pol 50% of the time. That said, metal shielded 2 pin Lemo (or ODU) seems like a smart way to reduce risk and is a more secure connection mechanically. If you're interested in going all 2 pin, the splitter noted below might be useful:

    https://www.bhphotovideo.com/c/produ...wer.html/?ap=y

    IAC, beyond the P-tap limitations and 12g SDI issues, I'd love to know what happens at the moment a V-mount battery is mounted or dismounted. Is this another opportunity for the positive pol to strike first? Do some plates have isolators or other electronics built in that prevent spikes from going anywhere? Are some low cost plates made without protection?

    Not sure what the cost, or impact on reliability might be, but why not a relay in the plate that doesn't close until both positive and negative are available? If I'm totally off base, I'd be happy to get schooled up on the subject.

    Cheers - #19
    I have taken apart quite a few V mount plates and batteries.... It's power straight never seen any isolators or wrong polarity protections or any such things. Soldered cable's that's it.
    Björn Benckert
    Creative Lead & Founder Syndicate Entertainment AB
    +46855524900 www.syndicate.se/axis
    VFX / Flame / Motion capture / Monstro
    Reply With Quote  
     

  2. #162  
    Senior Member Robert Hofmeyr's Avatar
    Join Date
    Sep 2009
    Location
    South Africa
    Posts
    886
    Quote Originally Posted by Björn Benckert View Post
    Its quite simple, for sure changing battery is just as bad as plugging in a Dtap. look at the pins on a V mount battery. + and - are just as long the chance that you connect it + first is very much 50% then the current will try to find the easiest way to ground, if that is your SDI cable then your I/O might go bye bye.
    I don't believe this is correct. Connecting the positive of a battery does not cause current to go to ground. Power needs a circuit. When only one pole is connected, there is no circuit, so the electrons don't flow anywhere. In contrast, when a d-tap positive makes contact first, the ground is already connected via the battery's negative terminal, so a circuit is formed: battery positive - power cable - monitor - SDI cable - camera - battery negative.
    Reply With Quote  
     

  3. #163  
    Senior Member Blair S. Paulsen's Avatar
    Join Date
    Dec 2006
    Location
    San Diego, CA
    Posts
    5,382
    Quote Originally Posted by Björn Benckert View Post
    I have taken apart quite a few V mount plates and batteries.... It's power straight never seen any isolators or wrong polarity protections or any such things. Soldered cable's that's it.
    That's all I've ever seen as well, Björn. IAC, I would still prefer a short run battery inside the plate. In addition to avoiding down time on brick swaps, it should keep the circuit energized so that the addition, or subtraction, of devices - including the brick itself - won't create an opportunity for current to seek an alternative ground path.

    Cheers - #19
    Reply With Quote  
     

  4. #164  
    Quote Originally Posted by Blair S. Paulsen View Post
    ...In addition to avoiding down time on brick swaps, it should keep the circuit energized so that the addition, or subtraction, of devices - including the brick itself - won't create an opportunity for current to seek an alternative ground path.

    Cheers - #19
    Thanks Blair, this is really interesting.

    So probably swapping BP-955 shouldn't be a problem for this reason (because as stated above the power circuit of the camera stays energized etc.). Btw can you choose from which battery to draw in the komodo menu? (I don't have mine yet..) Because it would probably be even saver if there would be a way to disable the battery bay via software where you're putting in a new brick (if this is possible please RED design a safe hotswap menu for the BPs, so that the hotswap feature gets usable aswell).

    As to solutions for continuous V-Mount power, I noticed the Core SWX plate has a lemo power in. So by the same principle you could connect a spare v-mount via d-tap to the lemo power in of the plate (first connect d-tap to v-mount then lemo to core plate :D) and you should be fine to because the circuit stays energized etc.

    Same thing on the ignite digi with their usb-c hotswap feature i presume.
    Last edited by Amarin Spörri; 04-29-2021 at 08:03 PM.
    Reply With Quote  
     

  5. #165  
    Senior Member Blair S. Paulsen's Avatar
    Join Date
    Dec 2006
    Location
    San Diego, CA
    Posts
    5,382
    Quote Originally Posted by Amarin Spörri View Post
    (snip) As to solutions for continuous V-Mount power, I noticed the Core SWX plate has a lemo power in. So by the same principle you could connect a spare v-mount via d-tap to the lemo power in of the plate (first connect d-tap to v-mount then lemo to core plate :D) and you should be fine to because the circuit stays energized etc. (snip)
    AFAIK, by providing another power source during a swap, you'd be protected. If there's a flaw in this logic, I implore anyone who knows why to post here. I certainly don't want anyone to fry anything based on my comments. I believe I have it right, or I wouldn't post it. That said, I don't have an EE degree or experience designing cameras, batteries or accessories.

    Cheers - #19
    Reply With Quote  
     

  6. #166  
    Quote Originally Posted by Blair S. Paulsen View Post
    AFAIK, by providing another power source during a swap, you'd be protected. If there's a flaw in this logic, I implore anyone who knows why to post here. I certainly don't want anyone to fry anything based on my comments. I believe I have it right, or I wouldn't post it. That said, I don't have an EE degree or experience designing cameras, batteries or accessories.

    Cheers - #19
    Thanks for specifying, Blair (and sorry for mixing up your name, I corrected it)

    Yes, let's see if someone disagrees. Would be nice to have some safe and affordable ways for continuous battery power on the komodo.

    Btw. Does anyone have woodencamera plate with the battery extension that allows for hotswapping by using a 955 and are using this feature? If you power the monitor with v-mount, it's circuit won't get continuous power, right? So that wouldn't be safe without switching off the cam and unplugging sdi? Or have wc taken measures to allow this? (because the hotswapping is an official feature of their plate and it wouldn't be practical just being able to use it with a phone as a monitor)
    Reply With Quote  
     

  7. #167  
    Something to consider: Several of my male D-tap connectors are made with miniature "banana plug" type pins. Banana plug pins have flexible, springy sides that expand to make contact with the socket female side. If these flexible sides get too compressed, they take a permanent set resulting in an intermittent connection with the female connector socket. I've actually had this happen; so, I'm not being paranoid about this happening. Considering the required RED procedure, if the negative pin is affected in this way, an intermittent connection would cause SDI failure, no matter how careful one is.
    Last edited by Bill Ravens; 05-10-2021 at 04:15 AM.
    Reply With Quote  
     

  8. #168  
    Senior Member Robert Hofmeyr's Avatar
    Join Date
    Sep 2009
    Location
    South Africa
    Posts
    886
    Red has updated the SDI protocol page: https://support.red.com/hc/en-us/art...to-SDI-Outputs. It's much clearer but still not sure about hot swapping bp-9s on the camera.
    Reply With Quote  
     

  9. #169  
    Quote Originally Posted by Robert Hofmeyr View Post
    Red has updated the SDI protocol page: https://support.red.com/hc/en-us/art...to-SDI-Outputs. It's much clearer but still not sure about hot swapping bp-9s on the camera.

    For me this updated SDI Protocol finally makes sense. I'm especially glad to read the following, under point 2 in the instructions:

    " - The camera's power state does not have an impact on SDI attachment sequence."

    Because when you earlier posted the feedback from Red support it clearly said that the camera needs to be shutdown aswell when plugging or unplugging SDI as can be seen here under point 3:


    Quote Originally Posted by Robert Hofmeyr View Post
    I got some feedback from Red support, but I'm afraid it seems to just add to the confusion. They keep referring to powering off the camera and monitor when adjusting or removing the SDI, but don't mention disconnecting the SDI to change a battery. Red's answers in bold:

    1. When you refer to "the power source for SDI accessories" does this include monitors being powered by their own battery?
    Yes, please power off the monitor when adjusting or removing the SDI even if the monitor is on battery power.

    2. In the warning in the manual you seem to be referring to any battery powering the camera or monitor. Is this the case?
    Yes

    3. Must I follow this order of operation when changing a BP-9 on the back of the Komodo, when there is a second BP-9 powering the camera?
    BP Battery or Direct DC in, the KOMODO should be powered off when adjusting or removing the SDI.

    4. There seems to be some confusion over whether this is a ground loop issue (eg the camera and monitor have the same power source and you plug in a d-tap to power the monitor and the positive makes contact first) or a differential grounding issue (eg the camera and monitor have different power sources, with different ground voltages). Please clarify what the issue is so I can do my best to avoid it.
    Yes, this may cause a grounding loop. When possible, avoid using P-Tap (also known as D-Tap) cables to power accessories. These cables are not shielded and may damage your camera.
    So if you want to hotswap a powersource, that also powers the monitor, switch off monitor, unplug SDI from camera, then hotswap, switch monitor on, connect sdi to camera. That sounds reasonable :D
    Reply With Quote  
     

  10. #170  
    Senior Member Bill Totolo's Avatar
    Join Date
    Dec 2007
    Location
    Los Angeles, CA
    Posts
    344
    Quote Originally Posted by Björn Benckert View Post
    A shit storm no doubt.

    They need to come up with a 12G Video isolation transformer very quick. I think this works but then you are on 12G: https://www.allenavionics.com/product-details/hd-vit-75


    Possibly this issue is part reason why the add to cart is not available on the red webpage. Seams like a remake of the video board would be in place so they dont have to do a total recall.
    Bjorn, this particular isolator does not work, at least not for me. I tried it with my Odyssey 7Q+ with no luck.
    Bill Totolo
    billtotolo.com
    Reply With Quote  
     

Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts