I’ve just got a fresh new RB750UP - it came with 5.6 so upgraded to 5.11 - and still can’t find the option to enable PoE, or read the current monitor.
Couldn’t find the fine manual to read on routerboard.com yet. Any hints would be welcome - or is this only a planned feature, to be released later?
/interface ethernet print detail
/interface ethernet set ether2 poe-out=
Thanks. What exactly does “auto” do, since it’s passive PoE so no 802.3af like detection signature is defined. Power is enabled after I plugged in a Loco5 though. Wasn’t brave enough to try if “auto” is safe for non-PoE gigabit ports though (should not enable power in that case).
And, how about the current monitor - mentioned on routerboard.com main page, but the RB750UP sub-page says “No” - is it there (need to wait for 5.12) or not?
RB750UP:
[admin@MikroTik] > /system health print
voltage: 12.2V
cpu-temperature: 44C
RB1100AHX2:
[admin@MikroTik] > /system health print
fan-mode: auto
use-fan: main
active-fan: main
voltage: 12V
current: 747mA
fan-speed: 8510RPM
temperature: 30C
cpu-temperature: 30C
power-consumption: 8.9W
i have tested with various Gbps ports (RouterBOARDs generally) and none of the ports where burned with poe-out=auto. Actually, even with PoE in on Gbit port it did not turn on the power since it differs from 100Mbps port.
Of course, to be 100% safe, use off setting where you do not need the power output as it is used as default value.
Also note that 750UP PoE out controlling chip will start on power up, so it will use settings on last boot up. And will work even if RouterOS is not booting for some obscure reason.
Board is not reporting current usage on the ports. Only indication available to users at the moment is - port will turn poe-out off if overload is detected.
Thanks. Nice to see there is overload protection. Any chance for at least total current reporting (board itself + all ports)?
Is that ATTINY461A upgradeable in the field (by RouterOS or firmware upgrade)?
We will add current reporting via software upgrade in one of the future versions.
Will the current reporting be the total for the device, or will it be reported separately for each port?
If I supply the 750UP’s power to the power input jack, is it possible to send PoE out on port1?
OK, first RB750UP in the field (small relay station) - not without some issues… Reporting them here in the hope Mikrotik can try to address them.
RB750UP powered from a CyberPower CS24U12V-12 power supply with 12V/12Ah battery backup.
All ports configured as a simple bridge for now. Previously it all worked with a dumb 5-port switch modified for PoE output.
Ports 2-5 with poe-out=auto connected via ~15m of FTP cables to some UBNT gear on the roof.
Port 1: WAN port of customer’s TL-WR340G (PPPoE client)
Port 2: Bullet2 (AP WDS, omni)
Port 3: Bullet5 (AP WDS, sector)
Port 4: Bullet5 (AP WDS, sector)
Port 5: NanoBridgeM5 (Station WDS, backhaul from a RocketM5 sector)
The ports are powered up in the order 5, 4, 3, 2.
But the Bullet2 won’t power up, even with poe-out=on. I’ve tried swapping ports too, and it’s always the Bullet2 that won’t power up, no matter which port it is on. That port LED won’t blink red even for a moment. It works fine with a UBNT PoE adapter in between though (RB750UP PoE out not used).
Another issue: when AC power fails, everything continues to run on battery backup as it should. But when it comes back, some of the PoE powered devices are turned off (it doesn’t happen every time, but quite often). I suspect it’s the fast rise of battery voltage (from 12V to 14V, when it starts being charged) that triggers the overload protection (short current spike due to capacitive load). It’s just too fast, that could also cause the Bullet2 issue (I don’t think it draws too much power, it’s just a simple low power 802.11b/g radio after all). Fortunately they power up again after a while.
you could try to step up the battery voltage to 24V that could sort out the overload protection kicking in. Also, you can check precisely how much power each device draws, that could be problem if you are using 12V to power the RB570UP then you get 10.5V on the output, if some of device is using MAX 8W, then 0.5A @ 11V is not near enough for the device to be powered.
So, best option is to use 24V.
4 Sectors with RB411AH/R52nM should work?
This would cleanup installations a lot.
should be no problems, since you are not even using high power cards. R52nM uses around 2W max, board itslef around 2W 
Switch chip not connected to ether1?
Cant set it as master or slave port.
So I’ve to use bridge to connect them all.
Is it fast enough to bridge 100MBit/s?
Next device should be a RB1100AHx2UP with dual Power connectors.
This will sit at the bottom of all my towers.
it configures same as new revision RB750, so if you set all-ports-switched=yes hen you will be able to set it as master-port for the rest of the ports.
Set this with winbox does not help. After rebooting it is disabled again.
Tried with 5.6 and 5.11.
Set ether1 as masterport: “chosen master-port does not support this feature”.
- I’d like to be able to use the RB750UP voltage monitor to measure the battery voltage (a step-up DC/DC converter would make it constant)
- if the problem is too much input capacitance in the radio, higher voltage will make it worse (will take longer to charge with the same current)
- 24V battery really means up to 28V, a bit too much to be safe for some radios (specified “up to 24V”); 18V (3*6V) battery would be perfect but such power supplies are unusual, the 12V ones are cheap
- why so much voltage drop (12V to 10.5V), does the RB750UP switch the power using bipolar transistors and not FETs?
- Bullet2 has no problem to start on a bench power supply, set to 9V and 200mA current limit (draws a little less than 200mA, initially just about 150mA before it fully boots; it could be more under high traffic, but the failing one doesn’t even power up for a fraction of a second)
BUT: this was tested in the lab, on a different Bullet2, powering up from a different RB750UP just fine - the devices that fail are at a distant location, difficult to access (need to ask someone in advance for permission to enter there, etc.); it still works fine with the UBNT PoE adapter, it might be partially broken in such a way that it works but draws much more power, but then I’d expect the extra 2-3 watts would burn something inside very quickly, and it has been working fine for a long time. A mystery…
To work around the “fast rise of supply voltage triggering overload protection”, I’ll try to add some extra capacitance on the output of the power supply (2200uF should be much more than inside the radios, absorbing most of that current spike and slowing down supply voltage changes).
RB750UP is up to 30V. Power chain on the board converts it to 5V as required by wireless part on integrated board, so there is nothing to worry about.
UBNT radios (which I’m powering from the RB750UP) are specified for 24V max, better to play it safe (especially legacy series, shipped with 15V PoE adapters and for some devices is said “max 18V recommended” probably due to lower efficiency of the old 34063 step down converter at high voltage - the new M series ships with 24V adapters, so might have a bit more margin). They work fine at 12V with 20m cables (good Cu ones, not CCA), and are not required to start at 10V - just continue to run until low battery cut off, after previously starting at 12V or more.
Could you provide more details how the PoE output is implemented (especially the auto detection and overload protection algorithm)?
Hi Normis, when you add this option?
in auto mode - router applies low voltage to the port and checks for voltage drop, if drop is within set parameters that correspond now from 3K ohm to 26K ohm, power is given on the port. When that happens short and overload is continuously checked and if either is detected action is taken upon. (more on the wiki manual)
for overload - it measures load and compares it to set value, if measured value is over set value power is turned off.
When this happens, is it logged?