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mayagamer
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My heX S can't power up Unifi 6 Lite

Fri Dec 10, 2021 3:02 am

As the spects states, heX S support passive PoE up to 57V out, Unifi 6 Lite support passive 48V PoE in. But I just can't make them work together. Anyway to fix it?
Also, how to set the voltage of poe out in webfig?
Thanks in advance!
Last edited by mayagamer on Sun Dec 12, 2021 4:48 pm, edited 1 time in total.
 
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vecernik87
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Re: My heX S can't power up Unifi 6 Lite

Fri Dec 10, 2021 5:39 am

hEX does not have voltage regulator. It has a simple passive pass-through so the output voltage will be same as input voltage. If your hEX is powered by standard 24V adapter, it will not be able to power U6L which requires 44-57V (either passive or 802.3 af/at)

hEX can output 48V or even 57V (therefore "up to...") but only if this high voltage is applied to the hEX itself.
 
mayagamer
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Re: My heX S can't power up Unifi 6 Lite

Fri Dec 10, 2021 7:00 am

Thanks bro

It's weird that I can't find anywhere mentioning it's pass through PoE on the page. https://mikrotik.com/product/hex_s

So do I have to buy another adaptor with 48v or a power injector?
 
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vecernik87
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Re: My heX S can't power up Unifi 6 Lite

Fri Dec 10, 2021 7:53 am

The page you linked actually says it, but in different words:
The port #5 can power other passive PoE capable devices with the same voltage as applied to the unit
I did not use the same terminology because I didn't even bother to open specs page and just fished it out of my memory.


You have three options:
  1. Get a 48V power adapter (normal DC powerbrick) and connect it to the hEX which will pass it to the U6L
  2. Get a 48V PoE injector and connect it to the hEX which will pass it to the U6L
  3. Get a 48V PoE injector and connect it to the U6L while leaving hEX on whatever adapter it is now.
 
mayagamer
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Re: My heX S can't power up Unifi 6 Lite

Fri Dec 10, 2021 10:58 am

Thank you very much!
I just ordered a PoE injector. I will mark this post "solved" when it works.
 
mixig
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Re: My heX S can't power up Unifi 6 Lite

Fri Dec 10, 2021 6:42 pm

I always use 48V adapter for that ourpise, with that I have remote control and ability to shut down port or turn off/on poe if something is wrong with the AP.
With PoE adapter you cant do anything
 
tangent
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Re: My heX S can't power up Unifi 6 Lite

Sat Dec 11, 2021 1:41 am

hEX does not have voltage regulator.

…which is another way of saying "passive." Whatever comes in is what goes out, less any resistive and reactive voltage drops.

…and it is these drops that account for these "48V" and "57V" distinctions. 57V is an absolute max for many PoE devices, with the voltage at the device being something above the 48V nominal they expect.

The problem you're having is that the hEX S ships with a 24V power adapter, which is fine for passive PoE in some cases, but not all.

Contrast active PoE where voltage into the power-supplying PoE device could well be lower than what it puts out through the magic of DC-DC conversion. That's what makes it an active PoE device. The electronics needed to do that cost money.
 
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vecernik87
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Re: My heX S can't power up Unifi 6 Lite

Sat Dec 11, 2021 1:45 am

@mixig:
With PoE adapter you cant do anything
If OP connects the PoE adapter to the hEX itself (Eth1) then power to the AP can be controlled remotely same as if the hEX was powered by DC adapter.
I understand purchase of PoE adapter as more universal - if the hEX is ever replaced with something else without PoE output (e.g. RB5009) the PoE adapter can be used to passively power the AP. With DC adapter, U6L can't be powered.

@tangent
…which is another way of saying "passive."
Correct. I tried to use different words because "passive" is already mentioned in specs so OP probably knows that but does not understand the true meaning
 
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mkx
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Re: My heX S can't power up Unifi 6 Lite

Sat Dec 11, 2021 10:54 pm

hEX does not have voltage regulator.

…which is another way of saying "passive."

Not really. In PoE context passive means that PSE (power sourcing equipment, hEX S in this exercise) blindly applies voltage to the port (well, it might detect short circuit, but that's about it). In same context active means there's some communication between PSE and PD (powered device, Unifi 6 lite in this exercise) in which PSE verifies that PD is compliant and that PSE power-out capacity is sufficient for PD's needs.

There are a few Mikrotik devices can be active (i.e. 802.3 af/at compliant) when they're powered with correct voltage (48V) ... and guess what, hEX S is one of them if one can trust product brochure.
 
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vecernik87
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Re: My heX S can't power up Unifi 6 Lite

Sun Dec 12, 2021 1:35 am

Can you please share a quote from the brochure? I went in details through it, without success to find anything about 802.3af/at PoE-out.
AFAIK, hEX S will stay passive no matter what and has no ability to netogiate power levels as af/at devices do.

I think you may be confused with hEX POE (RB960PGS) which has this weird active/passive combination, depending on input voltage.
 
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mkx
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Re: My heX S can't power up Unifi 6 Lite

Sun Dec 12, 2021 10:49 am

Ah, I wasn't reading brochure carefully enough, indeed it mentions 802.3 af/at only in PoE in section. Example of device behaving as I was explaining (802.3 af/at on PoE out if powered by appropriate voltage) is CRS112-8P-4S-IN (the supplied power adapter is not suitable) ... actually most (if not all) of Mikrotik devices capable of 802.3af/at PoE-out are the same way because all Mikrotik devices accept wide range of input voltage but for 802.3af/at much narrower range is acceptable.
 
mayagamer
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Re: My heX S can't power up Unifi 6 Lite  [SOLVED]

Sun Dec 12, 2021 4:47 pm

Thank you guys! Learnt a lot from your conversation.

I just got the PoE injector. It works only when Ether1 is set to force on. If set auto, it shows "wait to load" all the time.
I don't understand why. maybe that's what passive means.

but as long as it works, I think I can say "problem solved"
Thanks again!
 
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vecernik87
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Re: My heX S can't power up Unifi 6 Lite

Mon Dec 13, 2021 1:18 am

It works only when Ether1 is set to force on. If set auto, it shows "wait to load" all the time.
I don't understand why. maybe that's what passive means.
Mikrotik's "passive" PoE in some devices is not completely passive - your hEX tries to detect if there is certain resistance betwen wires before sending the power through. Unifi uses similar passive PoE approach so it is compatible, but different enough, that it does not get detected automatically. (it would get detected if your hEX supported af/at).

Thats why you had to force it. however, BEWARE - do NOT plug anything else to the Eth5 while PoE is in "forced" mode. It could easily burn your other device.

Details can be found here: https://wiki.mikrotik.com/wiki/Manual:P ... Monitoring

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