Dahua 2MP 25x Starlight IR PTZ Network Camera (SD49225T-HN)

mpbcam · Feb 23, 2017

mpbcam said:
... now I'm curious and will have to check it out.

Yeah, according to the specs, it's supposed to work like this (quoted from POE Explained - Understanding and using Power over Ethernet):

The final stage after detection and classification of a newly connected device is to enable power: the 48V supply is connected to the cable by the PSE so the PD can operate. Once enabled, the PSE continues to monitor how much electrical current it is delivering to the PD, and will cut the power to the cable if too much, or not enough, power is drawn. This protects the PSE against overload, and ensures that POE is disconnected from the cable if the PD is unplugged.

My guess (and just a guess, based on the outcome) is the PoE injector in question didn't do that and it started lowering the 48V as a result of the increased demand. I suppose it would matter if the heater was inductive or resistive... based on what happened I'd assume it was inductive (heater coils).

hmjgriffon · Feb 23, 2017

It was running round the clock while it was alive.

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hmjgriffon · Feb 23, 2017

So using this is actually dangerous, or only of you plug POE+ into it? WS-POE-8-48v60w Passive 10/100 Power over Ethernet PoE Injector for 8 IP Cameras, VOIP Phones or Access Points, 48 volts, 60 Watts Total Power

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nayr · Feb 23, 2017

yes, those passive devices are very dangerous.. plug a non PoE device into it and its still gonna get power and likely nuke the network interface.. if your lucky.

there's no negotation going on w/passive PoE, whereas Active PoE is safe for non-poe devices as they wont perform the handshake to enable power delivery.

hmjgriffon · Feb 23, 2017

nayr said:
yes, those passive devices are very dangerous.. plug a non PoE device into it and its still gonna get power and likely nuke the network interface.. if your lucky.

there's no negotation going on w/passive PoE, whereas Active PoE is safe for non-poe devices as they wont perform the handshake to enable power delivery.

Better order that Poe midspan soon then lol

SvenV · Feb 23, 2017

Brian Martin said:
The Camera requires POE+ to operate.
SD49225T-HN | Dahua Technology

That's what my POE switch has, so should be ok

EMPIRETECANDY · Feb 23, 2017

hmjgriffon said:
Yes, I used one of those little WS whatever injectors, camera ran fine for like a week, I played with everything even cranking the IR up all the way and never any issues so I'm still suspect on the heater thing but it died from something.

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No problem, we get them back and ask dahua to fix it. So all guys be careful for the power supply for the cams

hmjgriffon · Feb 23, 2017

EMPIRETECANDY said:
No problem, we get them back and ask dahua to fix it. So all guys be careful for the power supply for the cams

yeah I'm planning to buy a real big boy POE+ midspan here very soon.

Chase · Feb 23, 2017

Does a single cat 5 cable running to this camera (or any ptz) from a Poe switch or Poe capable nvr power the camera?

Or do you need an additional power supply?

hmjgriffon · Feb 23, 2017

Chase said:
Does a single cat 5 cable running to this camera (or any ptz) from a Poe switch or Poe capable nvr power the camera?

Or do you need an additional power supply?

if it's POE+ coming from the NVR or switch you are good.

hmjgriffon · Feb 23, 2017

Just ordered the same Poe midspan Mr @nayr has

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Zeddy · Feb 24, 2017

I just picked up an Edimax 802.3at midspan from Jaycar. Works great, I can't wait to get it mounted out front.

Zeddy · Feb 25, 2017

It's currently 38c here and the cameras OSD is showing 56c. How's everyone elses doing?

ldasilva · Feb 25, 2017

43f outside camera 83f

nayr · Feb 25, 2017

I ususally see about +20C over ambient always on my Black Face PTZ, thats not air temp.. thats cpu temp

wantafastz28 · Feb 25, 2017

47F out, 84F Camera. 30x hni though..

Semper Gumby · Feb 26, 2017

In the installation guide, to reset the camera or add an SD card it says open the rear cover. To open the rear cover do you remove these screws? Thanks.

hmjgriffon · Feb 26, 2017

Semper Gumby said:
In the installation guide, to reset the camera or add an SD card it says open the rear cover. To open the rear cover do you remove these screws? Thanks.

Yes

Semper Gumby · Feb 26, 2017

hmjgriffon said:
Yes

Thanks, the screws are torqued in there pretty good. I tried using a philips head, but they would not budge. I don’t intend to use an SD card, but if I ever have to reset it, I may have problems.

Zeddy · Feb 26, 2017

It does have a little bit of blue locktite on the threads, but it should remove easy enough. If you do get it open watch out for the gasket in there, mine seemed a little too large for the groove it was sitting in, had to make sure it was in as best it could. I did have a few rounded screws on mine, I think someone was a bit over zealous during assembly.

Dahua 2MP 25x Starlight IR PTZ Network Camera (SD49225T-HN)

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