Community discussions

Bdfy
just joined
Topic Author
Posts: 5
Joined: Wed Aug 15, 2018 3:31 am

### POE Problem

Hi, I use mikrotik hex s and hap ac2 ( hap ac2 - poe in ). hex s has 24V 1,2A power supply, but hap ac2 works unstable - I think it does not have enough power. What do I need to do - replace the power supply with a more powerful one?

pukkita
Trainer
Posts: 2982
Joined: Wed Dec 04, 2013 11:09 am
Location: Spain

### Re: POE Problem

hEX S max power draw = 11W
hAP ac2 max power draw = 15W

Total maximum power draw = 26W. hEX S PSU is 24V @ 1.2A = 28W.

Tight, but these are maximum power draw values. Have you tried powering the hAP ac2 on its own to see if is still unstable? How long is the cable going to the hAP ac2?

Yes, you can test replacing the PSU with a more powerful one.
Simplicity is the Ultimate Sophistication - Da Vinci
Getting the most out of this forum

Bdfy
just joined
Topic Author
Posts: 5
Joined: Wed Aug 15, 2018 3:31 am

### Re: POE Problem

I bought a more power PSU ( 24V, 2.5 A ), but problem not solved. Cable 15 m maximum. I think that protection by current (500ma) in the device on hEX S works. To power the HAP AC2 I had to use POE RBGPOE + Hex S ( from single PSU 24V, 2.5 A ) - all work fine. Why then the support POE is made on hEX S?

mkx
Forum Guru
Posts: 2825
Joined: Thu Mar 03, 2016 10:23 pm

### Re: POE Problem

Why then the support POE is made on hEX S?
One thing is limitation on PoE out current on some devices. I guess it is nice to have possibility to power some low-powered device directly off main router or switch. Example of such device would be simple WAP - single frequency, not many Tx chains.

PoE in is a completely different matter, sometimes it is handy to provide power to higher-power device over UTP cables. In such cases one use RBGPOE injector.

BTW, in some production environment it is not sound to have single power source (e.g. one switch) if that one doesn't have highly advanced power management built in (and basic PoE out devices by Mikrotik don't have very sofisticated power management built in). It can easily happen that malfunction of one device takes down all other devices, powered from same power source. Another thing not to be done IMHO is daisy-chaining power supply (e.g. switch -> device1 -> device 2) as power overload can easily happen taking down both PoE powered devices.
BR,
Metod

pukkita
Trainer
Posts: 2982
Joined: Wed Dec 04, 2013 11:09 am
Location: Spain

### Re: POE Problem

Other Mikrotik PoE switches can output up to 1A per port. Don't know the specific case for the hEX S as is a recent device and not a word about output limits on its last port on the specs, so it may be the case...

Again, this is the Maximum power draw by hAP ac2, won't be surprised if average draw is less than 300mA.

Did you force poe to on on the hEX S when powering the hAP ac2 or left it on auto?
Simplicity is the Ultimate Sophistication - Da Vinci
Getting the most out of this forum

OndrejHolas
just joined
Posts: 16
Joined: Mon Jul 30, 2018 5:54 pm

### Re: POE Problem

Hi, I use mikrotik hex s and hap ac2 ( hap ac2 - poe in ). hex s has 24V 1,2A power supply, but hap ac2 works unstable - I think it does not have enough power. What do I need to do - replace the power supply with a more powerful one?
Hi, I have similar problem here with these two boxes, but my hAP ac2 does not power up at all and hEX S' ether5 LED periodically (approx 1s) blinks red for short time (<100ms). Before hEX S, the power supplying box was RB2011 with PoE-out on ether10 and I've experienced no problems with powering hAP ac2.

I've tried to connect hEX S' port ether5 to:

- hAP ac lite - ether1
- hEX lite (RB750r2) - ether1
- RB2011 - ether1

and all these boxes started when powerfed from hEX S.

Just another experiment, I've connected hEX S' ether5 with PoE-out turned off to hAP ac2 ether1 and powered the hAP ac2 via external adapter. After hAP ac2 started, I've enabled PoE-out on hEX S' ether5 and disconnected external adapter from hAP ac2 - and the hAP ac2 continued to run. It seems that hAP ac2 causes current peaks that hEX S cannot sustain or some form of overcurrent protection cuts off the power... although no messages related to poe-out were logged.

Ondrej

OndrejHolas
just joined
Posts: 16
Joined: Mon Jul 30, 2018 5:54 pm

### Re: POE Problem

Did you force poe to on on the hEX S when powering the hAP ac2 or left it on auto?
On hEX S there are only two PoE-out modes - off and forced-on. Auto mode is not configurable:
``````/interface ethernet poe> set ether5 poe-out=auto-on
failure: This model does not support poe-out auto-on mode``````
Ondrej

pukkita
Trainer
Posts: 2982
Joined: Wed Dec 04, 2013 11:09 am
Location: Spain

### Re: POE Problem

I see... agree with you, definitely looks like the hAP ac2 power draw at boot kicks the power draw protection.

Which ROS version on the hEX? Firmware? (system > Routerboard?)

This could be either a hardware limitation on the hEX S, or maybe something fixable by upgrading POE firmware, as it was the 500mA -> 1A for older poe-out routerboards in the past.

Would try latest 6.42.7 (make sure firmware is updated on System > Routerboard too). Failing that, would write support, linking to this post.
Simplicity is the Ultimate Sophistication - Da Vinci
Getting the most out of this forum

OndrejHolas
just joined
Posts: 16
Joined: Mon Jul 30, 2018 5:54 pm

### Re: POE Problem

Would try latest 6.42.7 (make sure firmware is updated on System > Routerboard too). Failing that, would write support, linking to this post.

Already at 6.42.7 (both ROS and firmware). I've just sent mail to support with details and link to this topic.

alexvdbaan
Trainer
Posts: 38
Joined: Sun Feb 22, 2015 12:12 pm
Location: Amsterdam, Netherlands
Contact:

### Re: POE Problem

I have several clients with RB2011 and poe port broken. Thought it was a coincidence but it appears to be that the poe is shutting down more often than not.

pukkita
Trainer
Posts: 2982
Joined: Wed Dec 04, 2013 11:09 am
Location: Spain

### Re: POE Problem

Alex, were the 2011 powering AC CPEs?

Ondrej, did you include a supout.rif file taken while the problem was happening? do so...
Simplicity is the Ultimate Sophistication - Da Vinci
Getting the most out of this forum

OndrejHolas
just joined
Posts: 16
Joined: Mon Jul 30, 2018 5:54 pm

### Re: POE Problem

Ondrej, did you include a supout.rif file taken while the problem was happening? do so...
I didn't include supout.rif in the support case, because the displayable PoE status (print/monitor) on hEX S didn't show anything bad and nothing relevant was logged (turned on logging all about "poe-out", regardless level), so there will be no useful info about the problem in supout.rif, I think.

Nevertheless, today support technician responded that they were able to reproduce the problem based on my description.

Ondrej

alexvdbaan
Trainer
Posts: 38
Joined: Sun Feb 22, 2015 12:12 pm
Location: Amsterdam, Netherlands
Contact:

### Re: POE Problem

Alex, were the 2011 powering AC CPEs?
Yes, in all cases they were providing power to wap ac

pukkita
Trainer
Posts: 2982
Joined: Wed Dec 04, 2013 11:09 am
Location: Spain

### Re: POE Problem

Yes, in all cases they were providing power to wap ac
Do same 2011 port powers a 100BT device fine?

I've experienced that, specifically when powering gigabit AC devices from 100BT PoE out ports.

First time with a 951Ui and a Netbox. Something "broke" on the 951Ui which wasn't able to power a gigabit/ac device (Netbox, wap AC, etc) and boot it successfully anymore.

Same port worked fine hile powering another 951, 750, Basebox, etc.

Sent a supout and report to mikrotik back in the day.

The second time I experienced it I stopped deploying those combinations; no 2011/951Ui powering any gigabit AC gear.

Be sure to properly ground 2011s... sensitive switch chip/ports.
Simplicity is the Ultimate Sophistication - Da Vinci
Getting the most out of this forum

simogere
newbie
Posts: 40
Joined: Fri May 24, 2013 11:54 am

### Re: POE Problem

Hi, I need a little info: my wAP ac is connected to a hEX PoE. The wAP is powerd only if the setting of Poe on hAP port is setted up to "forced on". With "auto on" it does not work. Reason?

Thanks, Simone

### Who is online

Users browsing this forum: No registered users and 41 guests