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Author Topic: 5520-PWR PoE question  (Read 277 times)

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Offline nothingincommon

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5520-PWR PoE question
« on: May 01, 2018, 10:06:03 AM »
So I setup my 5520-24T-PWR and everything is working great. I can access my camera and its video just fine.

When I connected the camera I was monitoring the PoE port section of the ERS 5000 web gui and i noticed it was just drawing power automagically.

The cam is 10/100mbps and supports 12 VDC 10%, PoE (802.3af). Is there anything i need to do or do devices regulate the power they draw?

My fear is damaging the camera if I have too much power going to it or if i have the wrong setting somewhere.

I checked on all the power saving options given in the settings.


Offline Telair

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Re: 5520-PWR PoE question
« Reply #1 on: May 02, 2018, 06:15:51 PM »
When the camera connects, as long as PoE is enabled on the port the switch will start supplying power to it.  Now the switch and device negotiate on the amount of power to send based on what class of power to send.  This can be done via a resistor between the powered pairs telling it how much power to send based on resistance or actively negotiated using the LLDP-MED protocol.

Class 1: Up to 4w
Class 2: Up to 7w
Class 3: Up to 15.4w (maximum 802.3af)
Class 4: Up to 30w (maximum 802.3at)
Class 5: Up to 45w
Class 6: Up to 60w
Class 7: Up to 75w
Class 8: Up to 99w
Class 8+: Over 99w (maximum 802.3bt)

So your camera won't draw too much power as it will negotiate with the switch how much to send to it.

Offline nothingincommon

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Re: 5520-PWR PoE question
« Reply #2 on: May 03, 2018, 10:10:34 AM »
Thats great info thank you. I feel better now.

Is there a best practice for protecting devices from a power surge, would standard surge protection be good enough?