Faulty Zyxel PoE switch or Dahua Dome operating limitation?

[f13dfx 0]

Hello all again,

 

My self-installed video surveillance system had been functioning flawlessly for 5 months.

 

Here is what I have:

2 x ACTi E32

1 x Dahua SD3282-GN 2Mp PoE PTZ Dome

1 x Zyxel ES1100-8p w/4 port PoE unmanaged switch

1 x Zotac 4770T Quad Core Mini-PC Win7 64bit Blue Iris @ 10% Processor Occupancy with all cams at full resolution & fps.

 

My Dahua's cable run is 75' (Outdoor Cat5e rated). Here is a link to it's specs: http://www.dahuasecurity.com/products/sd3282d-gn-288.html

 

I'm running this off one of the PoE ports off the Zyxel switch whose max per port output is 15.4 watts (without external power source). The Dahua is under an eave above the front of my house monitoring my front driveway. You may have seen video that I've posted on one of my earlier posts. It has been working flawlessly for 5 months. I just noticed that recently in the evenings, the connection just drops & I get no video on Blue Iris (both PC & iPhone 5s) & IP Cam Lite on my iPhone 5s. I managed to reboot the camera by unplugging & replugging the Cat5e connection from the Zyxel switch.

 

All cameras are running on max resolution, fps & mbps! I'm just wondering since the Dahua consumes 15 watts of power that when the nightvision (no IR LEDs) kicks in does it consume more power so that the Zyxel cannot handle it? Or is the Zyxel switch dying? I've power cycled it once yesterday, everything was fine, but then when I woke up today, the Dahua had cut out again!

 

Does the combination of the 75' cable run along with the Zyxel's max 15.4 watt PoE port output cut down on the power that's actually feeding the Dahua Dome? I'm thinking of going to the local PC store & buying a TrendNet Power Injector to isolate the power going to the Dahua. It only puts out 15.4 watts though, but it will be dedicated (http://www.memoryexpress.com/Products/MX45841). I really wanted to get this one by LTS since it puts out up to 30 watts: http://www.computers-canada.ca/store/products/1027021492/POE-I100H/LTS/

 

One last question. Although this camera is under my house eave, the specs say the Working Environment should be Less than 90% Relative Humidity. Well where I live in the Pacific NW, when it rains from days on end (which it has been lately) it is usually 100% RH. My connections are well protected with Butyl insulation tape. Could this be the problem? I do not see any condensation in the housing or dome glass cover.

 

Any advice on what to try would be greatly appreciated!

 

Thanks in advance!!!

Edited March 9, 2014 by Guest

[buellwinkle 0]

Try unplugging the other cameras to see if the problem goes away.

[f13dfx 0]

Process of elimination. Good plan!

 

I'll update status tomorrow.

[drocer 0]

Who ever started this "full 15.4W port" thing needs to stop saying it. It's not even correct:

 

15.4W PSE only gives 12.95W PD.

 

http://www.dahuasecurity.com/products/sd3282d-gn-288.html

 

15W PD requires ~16-18W PSE

 

You need a switch that does PoE max (802.3at) for that one camera. e.g. ZyXEL GS1100-8HP

 

That LTS 30W injector should work. FYI, the MAX you will get at the end is 25.5W.

[MaxIcon 0]

This limitation is due to power drop along the cable.

 

With a short cable or a larger gauge wire, you'll get more power at the device for a given current. This is a good reason to use cat6, even though few cams run over 100Mbps, since the wire gauge is slightly larger.

 

Presumably, this minimum power delivery rating is based on maximum spec cable length and minimum spec wire gauge.

[drocer 0]

This limitation is due to power drop along the cable.

 

With a short cable or a larger gauge wire, you'll get more power at the device for a given current. This is a good reason to use cat6, even though few cams run over 100Mbps, since the wire gauge is slightly larger.

 

Presumably, this minimum power delivery rating is based on maximum spec cable length and minimum spec wire gauge.

 

Or take 10 seconds to learn about PoE and don't waste money on cat6. You can't power a class 4 device with a class 3 PSE.

[f13dfx 0]

drocer:

Would a IEEE802.3af device power up & accept higher wattage than the spec of 15.4watts or 12.9watts at PD?

 

I'm trying a 12vdc power supply direct & all's good so far at max res.

[drocer 0]

drocer:

Would a IEEE802.3af device power up & accept higher wattage than the spec of 15.4watts or 12.9watts at PD?

 

I'm trying a 12vdc power supply direct & all's good so far at max res.

 

If a 802.3af device needs more power than the spec (12.95W at PD), it's a 802.3at / PoE+ device that was not labeled correctly. That PTZ camera you have is rated by dahua as a 15W PD 802.3af; that's mislabled to me as the spec can't deliver that. I'm sure you've asked why did it work so long without issue? Chinese switch running a chinese camera operating at the end of it's designed spec; IR lights from your other cameras kicking on at night likely caused the switch to prioritize the ports in numeric order.

 

Running a separate DC power supply or injector will fix your problems. A more elegant solution would be a 802.at/PoE+ switch. Either way works.

[MaxIcon 0]

This limitation is due to power drop along the cable.

 

With a short cable or a larger gauge wire, you'll get more power at the device for a given current. This is a good reason to use cat6, even though few cams run over 100Mbps, since the wire gauge is slightly larger.

 

Presumably, this minimum power delivery rating is based on maximum spec cable length and minimum spec wire gauge.

 

Or take 10 seconds to learn about PoE and don't waste money on cat6. You can't power a class 4 device with a class 3 PSE.

 

This is basic engineering, not POE. The 12.95W spec is worst-case, and is due to wire resistance at max power load. The extra power is dissipated along the cable due to current and cable resistance.

 

Lower resistance wire and shorter runs will decrease the total cable resistance and increase the power available at the end of the cable.

[drocer 0]

This limitation is due to power drop along the cable.

 

With a short cable or a larger gauge wire, you'll get more power at the device for a given current. This is a good reason to use cat6, even though few cams run over 100Mbps, since the wire gauge is slightly larger.

 

Presumably, this minimum power delivery rating is based on maximum spec cable length and minimum spec wire gauge.

 

Or take 10 seconds to learn about PoE and don't waste money on cat6. You can't power a class 4 device with a class 3 PSE.

 

This is basic engineering, not POE. The 12.95W spec is worst-case, and is due to wire resistance at max power load. The extra power is dissipated along the cable due to current and cable resistance.

 

Lower resistance wire and shorter runs will decrease the total cable resistance and increase the power available at the end of the cable.

 

Worst case is the best case with the classes. Class 3 max is 12.95W. If the PD requires 15W, it's a class 4.

 

Axis labels their cameras correctly for the max power available:

http://www.axis.com/files/datasheet/ds_p13_p13e_47290_en_1204_lo.pdf

 

I agree and understand what you're saying perfectly, but it doesn't really help the OP and his problem. e.g. say 15.4W over Cat6 ends up 14.95 at the PD; what is he to do then? Buying the correct switch or using a high powered injector is a better solution. People need to follow the PoE classes and drop the obsession with "full 15.4W" that seems to permeate this board.

[MaxIcon 0]

Yes, assuming Dahua's spec is correct (which is always a big assumption with them), they have it classed incorrectly. Since the Zyxel's unmanaged, it's not easy to determine actual power draw without using an inline device to read it.

 

For OP, since it worked for a while, it appears something changed recently:

 

- Cable resistance increase, which is possible if there's a mediocre crimp with a lot of current flowing, or if the cable is copper clad aluminum.

 

- Higher current draw; I've had one Dahua overload, then kill the IR LEDs. This would be easy to check by looking at the LEDs in low light to see if some are brighter than the others. Other internal problems could cause this as well.

 

- Switch not putting out as much as it used to; Zyxel's fine for inexpensive gear, but inexpensive gear tends to not be as reliable as the big boys, and it would be running right at the edge.

 

If it were mine, I'd probably re-crimp the cable ends, because that's fast and easy. Still, it's close to or over the edge, so a higher power supply would be the long term fix.