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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

The SDI issues

Blair S. Paulsen said:
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/product/1600677-REG/camvate_c2566_1_to_3_power.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
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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 said:
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.
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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.
 
Björn Benckert said:
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.
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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
 
Blair S. Paulsen said:
...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
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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.
 
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Amarin Spörri said:
(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)
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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
 
Blair S. Paulsen said:
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
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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)
 
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.
 
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Robert Hofmeyr said:
Red has updated the SDI protocol page: https://support.red.com/hc/en-us/articles/360057166453-Preventing-Damage-to-SDI-Outputs. It's much clearer but still not sure about hot swapping bp-9s on the camera.
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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:


Robert Hofmeyr said:
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.
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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
 
Björn Benckert said:
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.
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Bjorn, this particular isolator does not work, at least not for me. I tried it with my Odyssey 7Q+ with no luck.
 
The new update on the powering and connecting sequence is much more clear. Basically turn on everything then connect SDI.

This also basically states that plugging an SDI cable while monitor and camera are running is not an issue.
 
Bill Totolo said:
Bjorn, this particular isolator does not work, at least not for me. I tried it with my Odyssey 7Q+ with no luck.
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On Facebook there has been a report that an SDI port got fried despite using an isolator. Hot plugging a D-Tap was most likely the cause. Meaning best protection is avoiding D-Taps plus the correct sequence.

I ordered the SWX Core EVO hotswap plate with Lemo outputs and went full Lemo for accessories. Meaning no D-Taps and no powering the camera down when changing batteries. Fingers crossed this will work without complications.
 
Leonard Frederic Caspari said:
On Facebook there has been a report that an SDI port got fried despite using an isolator. Hot plugging a D-Tap was most likely the cause.
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Isn't the isolator made specifically for the reason of preventing this setup malfunction?
 
<SMH> you know, the mechanism of failure has been discussed ad infinitum. ANYTIME "+" power is connected without there being a suitable ground path (like the "-" battery pole) the momentary inrush current will seek the easiest path to ground. This means, if the SDI cable is connected, it will use the ground path of the SDI cable, burning out the SDI electronics. The way to protect the SDI board is to not give battery power that ground path thru the SDI circuitry.

So, if, for example, the battery (-) is an intermittent connection (as I've reported above) , you stand the chance of burning out the SDI board. The damage happens because the inrush of current thru the sdi electronics is more than the digital level (<< .1 amps) the electronics are designed to handle. Isolators, like the ones referenced, work by having an internal capacitor to absorb inrush current before it can damage anything. These capacitors are very small and their capacity to absorb the current is very small and fleeting. If the voltage/current spike exceeds the capacity of the protection capacitor, you may as well not even have that capacitor in the line. The downside of these protective capacitors is that they also absorb the minute fluctuations in the digital signal, many times completely isolating even the digital signal.
 
Quick question, and forgive me is this has been covered before.

Would this Titla V mount plate help?

https://www.bhphotovideo.com/c/product/1579553-REG/tilta_ta_t08_bpv_b_dual_canon_bp_to.html

You could power your Onboard monitor from the Lemo Ports, and not have to deal with P-Tap, etc.

And in studio situations its even better, as you can plug into wall/AC, and then when you unplug the camera (to move it, etc) the cam just switches to battery but never powers down.

Meaning once you power up the first time, you could leave the SDI plugged in all day until you power down end of day (when you'd detach SDI again as last thing you do). Ie this leaves the SDI cable/port out of harms way over course of day, which is our goal right?

Sorry, this is making me anxious too - so trying to see if this logic is sound.

We've been monitoring this feed/issue, and really trying to find a workaround/solve that's practical.
 
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We still don't have any good solutions.

The main problem here is that a normal shoot that uses batteries on the monitor and the camera can't be bothered with a slow and tedious cable management just to be able to change batteries on either the camera, the monitor or both.
It might be that you need to "keep going" fast and you need to change batteries and get up and running asap. This whole thing makes the workflow extremely impractical and extremely prone to the slightest mistake in a high-stress environment.

So far, I've yet to hear any innovative ideas on how to failsafe against this. The isolator was a good idea but seems to not work anyway. What else can we do?

Can we use a converter instead? Like the SDI to HDMI converter before attaching the monitor? Or does that do nothing since the signal is still going through everything?

I still think that we need a native monitor from Red. Something we can use that doesn't rely on the SDI port. The biggest problem we have right now is that SDI is the ONLY way to monitor with any high quality. And if it's impossible to make a monitor powered off the camera, just make a Red monitor that uses BP batteries that connects to the top instead. I just want a solution to this because right now we either risk a lot by using SDI monitors or we have to use the Komodo Link which isn't close to good for critical viewing.

Maybe an updated expansion module underneath that has HDMI or something for higher quality viewing without high risk of damage... I mean... anything from Red that helps us have a good second option to the onboard SDI would be helpful. I really hope Red is reading all this and understand the point of this thread and that it's a request for solutions.
 
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