Troubleshooting POE on HFW4300S V2

[DaveK]

Well, the problem with my camera isn't the RJ45 jack/keystone as I thought it was.

This is a camera that has been in service for a year or so, and has previously had no problems. Now, when I'm connected to my TPLink POE switch, the camera does not power-up. I have tried each of the other 3 POE ports on the switch, and the result is the same. I have tried new cables, and cables that work with other cameras, and still no success. There appeared to be a bit of corrosion on the keystone contact wires, but the problem remained after cleaning those to bright metal, and I definitely have continuity through the keystone to the Dahua camera cable.

If I use an external 12V power supply, connected to the 12V pigtail, the camera works just fine with the TPLink switch (not using the POE ports). If I use a POE injector (48V, 0.5A, single-port output), the camera also powers up and works just fine. I have a second TPLink POE switch, and the camera does not power up with that one either.

Any suggestions for what to do next? I really don't want to dedicate a separate POE injector, or 12V power supply to just this one camera.

 

[Kawboy12R]

Try a hard reset on the camera. My guess is that the switch is asking the camera "Are you PoE?" and the camera isn't responding as it should. A hard reset may or may not fix that. While the cam's PoE still works the switch doesn't think it does so it isn't turning it on. Your PoE injector probably doesn't ask and just sends it anyway.

 

[DaveK]

I guess my next question would be "How do I do a hard-reset on this camera?" I've disassembled it and can find no obvious reset switches or jumpers on the camera board.

 

[Kawboy12R]

Should be in the firmware. Reset to factory settings. That should fix any fixable glitches.

 

[smoothie]

You could take the camera down and connect it to the switch with a single (tested and known to work) patch cable. That would rule out the connections between the switch and the normal camera position. If the camera boots up successfully with just a patch cable then it would be time to check the connections on the run to the cameras install location. If the camera doesn't boot successfully then you know it is the camera having issues. I don't know enough about cameras yet but you might look into if it is possible/advisable to reapply the firmware to the camera.

 

[DaveK]

Well, the problem is definitely within the camera. Other cams work fine with the cable to this cam, and other, verified cables don't change the POE behavior of the camera.

I haven't done a reset or firmware upgrade, as I consider that as a last resort before junking a camera that was once working properly. Also, I'm guessing that POE is not part of the camera firmware. I think the POE "logic" is entirely within the "dongle" that splits the camera pigtail into an ethernet connection and a 12VDC input.

 

[nayr]

that is correct, PoE 'logic' is hardware based.. how could software tell the PoE supply to do anything before its been powered on and booted? it cant.

active power over ethernet logic is simple, its supposed to look for a very specific range of resistances on the PoE pair.. if its absent the injector/switch is not supposed to connect PoE, if it is then it activates power..

source: https://en.wikipedia.org/wiki/Power_over_Ethernet#Powering_devices

A [PoE Device] indicates that it is standards-compliant by placing a 25 kΩ resistor between the powered pairs. If the [PoE Supply/Switch] detects a resistance that is too high or too low (including a short circuit), no power is applied. This protects devices that do not support PoE. An optional "power class" feature allows the [PoE Device] to indicate its power requirements by changing the sense resistance at higher voltages. To stay powered, the [PoE Device] must continuously use 5–10 mA for at least 60 ms with no more than 400 ms since last use or else it will be unpowered by the [PoE Supply/Switch]

is your PoE light coming on w/the camera plugged in at the switch/injector? if so its getting the 'signal' at that end.. does it work on the 12v dongle? if so you can work around the issue with a PoE 12v Splitter: http://www.amazon.com/iCreatin-ethernet-Splitter-Adapter-Compliant/dp/B00SM196AE/

 

[DaveK]

Thanks! That's pretty much what I thought was going on.

No, the POE light on the switch does not light with this camera. The POE splitter would certainly do the job, but I'll opt for the "dumb" POE injector for about the same price. Weatherproofing the connections for the splitter would be troublesome at best. With the injector, I can still use the protective "boot" to keep moisture out of the RJ45 connection at the camera end.

I will probably replace this camera with a newer HFW1320S, then use the old camera as an emergency spare, since its video functions aren't an issue once I get it powered up.

As an aside, do you have any ideas why the POE dongle on the camera might have failed? I'm suspecting that I didn't get a weathertight seal on the RJ45 connection and moisture intrusion resulted in a short that damaged the dongle.

 

[nayr]

thats the most common culprit for dead poe.. water ingress into the connector.. might be able to shine a light into the plug and see some blackened connections.

self sealing tape stretched when wrapped, with a good protective layer of quality uv stable electrical tape on top is the best way to protect these connectors for the long haul.
http://www.harborfreight.com/1-in-x-10-ft-self-bonding-super-tape-61414.html

 

[DaveK]

I'm partial to using the self-fusing silicone tape to provide the "belt-and-suspenders" approach to sealing the connection in very exposed locations. I haven't tried the Harbor Freight version, but it should work pretty well if used properly.

I've had a couple of the Dahua cams arrive without the weather-boot, and the self-fusing tape has always worked well.

 

[nayr]

the HF stuff is easy to locate in most of the US, and cheap as shit.. Ive definitely worked with better quality stuff in my days, but its hard to find the good stuff in small enough quantities you need for a small install.. and the name brand 3M stuff is not cheap.. Local Big box store has some stuff thats no better than HF for 2x the price IIRC.

it'll get the job done, like most HF junk.. but quality is not there for the guys who have to use it every day, just the backing tape is too much a hassle you'd never want if you were hanging off a radio tower or a service pole.

 

[DaveK]

LOL! I hear you about the HF Quality trade-off. But it can be used to your advantage... I know a guy who bought one of those HF angle grinders, plus the extended warranty. When the beast expired in about 6 months, he took it back for a replacement, and bought the extended warranty on than one. He's a professional welder, and the grinder gets used a lot. He says he's far better off paying for the extended warranty every 6 months as opposed to buying a brand-name grinder every 18 months or so.