Multi Power 12V for Camera Converter

I need ton connect 4 camera converter on power 12V with 50m cable.
Datavideo PD-3 is a Power Distribution Center 8x12V output on XLR 4p.
Is it possible to connect this output 12V 3.5A to a camera converter ?
I know i have to find XLR 4p cable to DC
(i read 12V 0.84A max on the small power supply of the camera converter)

Well i ran some calculations for you.

On 50 meters with 12V 0.84A you have a voltage drop of 0.98 volt across the cable in theory. Which will probably result in a higher drop in practise.

I understand your problem while running the camera's on the battery, your converters need power.

Is there any way to power them of a battery? (like a sony battery holder with power outlet?) Or V-Lock battery if at hand?

just me 2 cents

Hello, i tested yesterday 50m cable and no problem with the small power supply of the camera converter (12V 0.84A):
12,17V exactly on the power output and 12,17V output 50m cable !!

How did you measure the voltage? The voltage drop depends on the current (as V = R * I). So without a significant load you will have only a small voltage drop on your 50m line.

Toby is right on this one.

There should be a voltage drop acroiss the 50 M cable. But indeed only when you put the converter on the other end.

Voltage drop should be theoretacly 0.98V if the converter would use the complete 0.84A

But we all know it is less then that as a power supply has always overhead.

But if it works for you and the converter keeps on working with ~11 volts (which will probally be the case) (i guess internal regulator to 5 and 3.3 Volt)

The Datavideo PD-3 is configurable to 14 volt (25 or 12 too) fore each individual outlet. Use 14V set-up to hit the cameras and converters. Voltage drop should be tolerable for each unit.

I don't anderstand "Drop" and why i must use 14V because it works with 12,17V output the 50m cable !
I used a voltmetre to measure the voltage

I don't anderstand "Drop" and why i must use 14V because it works with 12,17V output the 50m cable !
I used a voltmetre to measure the voltage

Wire is not a perfect electrical conductor, and has a certain resistance per meter. Heavier gauge cable has less resistance per meter than lighter gauge cable. Because of this resistance, there is a voltage drop between the power supply end of the cable compared to the camera end. As you would expect, a longer cable will create a higher voltage drop than a shorter cable.

The point that is being made is that because the camera requires a certain minimum voltage to operate properly, it will be necessary for the power supply to produce a somewhat higher voltage so that even after the drop in the cable, there is enough remaining for the camera.

Most cameras are capable of accepting an input up to somewhere around +16 volts without damage; if you set up the supply to produce this, your camera will continue to operate even if it produces a 4-volt drop.

Does that help?

-- Jeff

The way I understand it, iherve has already measured the voltage on the 50m cable and found that it does not drop.

@iherve:

I don't have much knowledge of this, but from what I understand, you need to measure the voltage when the cable is connected to something. Did I interpret your answers correctly, TobyDE and Jeff?

The way I understand it, iherve has already measured the voltage on the 50m cable and found that it does not drop.

@iherve:

I don't have much knowledge of this, but from what I understand, you need to measure the voltage when the cable is connected to something. Am I interpreting your answers right, TobyDE and Jeff?

There is always voltage drop across any given length of cable. By Ohm's law, the voltage drop equals the current (in Amperes) multiplied by the resistance (in Ohms). A cable as long as 50 meters will have easily measurable voltage drop -- but remember, the camera needs to be connected and running to make this measurement.

Approaching this theoretically, here's an example. Let's say that your camera draws 0.5 amperes of current at 12.0 volts. Moreover, let's assume that you have 50 meters of #16 gauge cable. Remember, since there is a positive feed and a negative return wire in the cable, that's actually 100 meters of wire in the circuit. The resistance of #16 wire is 0.0132 Ohms per meter, or a total of 1.32 Ohms for the 50 meter cable assembly. Applying Ohm's law to calculate the voltage lost in the wire:

E = I • R (E is voltage, I is current, R is resistance)
E = 0.5 • 1.32
E = 0.66 Volts

So in order to actually have 12.0 volts at the camera, the power supply would have to produce 12.66 volts.

As a practical matter, some cameras consume higher current (which would increase the voltage drop); also, some power cables use lighter gauge wire, which would have a higher resistance per meter and therefore would lead to a higher voltage drop.

-- Jeff

but remember, the camera needs to be connected and running to make this measurement.

iHerve, You have to measure the voltage with connected camera !

You have two resistors in a chain - the cable and the camera. At both, you have a drop, which is proportional to their resistance.

Using Jeffs formula:

E = I • R (E is voltage, I is current, R is resistance)
E = 0.5 • 1.32
E = 0.66 Volts

Form Jeff's first fomula to "I = E / R".
When the amperage is I, so it is the same amperage in the camera and in the cable. So
"E = I • (R Cable + R Camera)"
and
"I = E Camera / R Camera = E Cable / R Cable" or better: "E Camera / R Camera = E Cable / R Cable"

->

E Camera / R Camera * R Cable = E Cable

When no camera is connected, the missing "Camera resistor" goes to endless. Camera's drop (can be 0 V to max 12 V, but however) devided by endless is zero (multiplicatad by 1,32 is also zero).

So, without camera, you measure full 12V voltage (E camera) at at the end of the cable - a drop near zero in the cable (E Cable)....

With a "real" Camera wich has a "normal" value for resistance you get a drop like described by Jeff.

I hope my english an my mathematics were good enough for understanding

Thank's ! I understand now. !!
"iHerve, You have to measure the voltage with connected camera !"

I will test today with camera connected and i will record during 8 hours. Then, i could verify if the playback is OK or if drops generate problems on the media...

Good test ?

Camera converter Somebody missed that i guess..

You have to measure the voltage at the converter side when the converter is connected. Only then you can measure the voltage drop. But if your converter works. Than it should be oke. As long as it is stable.

It could help to connect the camera to the converter as the converter will have more to do and the processor needs more power. If everything stays stable your oke to use it.

Yes My test will be :
CameraConverter Power supply > 50m cable > CameraConverter
Sony PMW-EX1 Power supply > 50m cable > CameraEX1
Camera EX1 > CameraConverter
CameraConverter > 50m Fiber optic > Studio converter > ATEM > Samourai recorder !

Oke Nice setup.

Wondering what the camera will do.. As they draw more power.. I thoughed you were to power the cams with battery's

I don't want to use batteries because the conferences are often during more than 7 hours per day..
So, camera converter is only 5 hours max and EX1 batteries too ...

Every things on supply power is better for me.

Hello, the test is successful !!
I did the test from the battery completely discharged.
8 hours recording error has no picture, no drops.
But the battery can be recharged while in use.
After use, when the camera converter is turned OFF, the battery takes its charge...

if you have to use the PD-3, you see the following link to the hint! [color=#0000FF]http://www.datavideo.info/en/Accessories/DDC-2512 http://www.datavideo.info/en/Accessories/DDC-4012[/color]

Datavideo DDC-4012 or DDC-2512 help you?

Thank's but i don't anderstand why i have tu use DDC-4012 or DDC-2512 with PD-3 because the PD-3 output 12V directly ! I just have to put XLR 4pin 50m to the camera ???