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POE Staggered Start
Posted: Fri Dec 16, 2016 6:19 pm
by sbbinc
Is POE Staggered Start on the WS-250-AC ?
We are running 1.4.5rc8
Re: POE Staggered Start
Posted: Fri Dec 16, 2016 6:29 pm
by sirhc
yes, I believe it is 500ms between port power ups
please upgrade to v1.4.6
Re: POE Staggered Start
Posted: Fri Dec 16, 2016 6:35 pm
by sbbinc
Oh, so Staggered Start is a built in fixed time, not something we can specify?
Re: POE Staggered Start
Posted: Fri Dec 16, 2016 6:54 pm
by sirhc
sbbinc wrote:Oh, so Staggered Start is a built in fixed time, not something we can specify?
No you can not configure it.
Why do you want to, 500ms is long enough to get past the inrush of most devices before powering the next device?
Re: POE Staggered Start
Posted: Fri Dec 16, 2016 7:36 pm
by sbbinc
On this actual unit, after a power outage, when the power comes back on, the switch keeps rebooting. If we unplug 4 of the attached POE powered devices it will reboot and then we plug in each device one at a time and all is OK.
total draw is approx 50 to 55 watts. 9 APs on 48V.
Thanks
Re: POE Staggered Start
Posted: Fri Dec 16, 2016 7:45 pm
by sirhc
Sounds like your UPS is not large enough?
What UPS are you running this on?
Re: POE Staggered Start
Posted: Fri Dec 16, 2016 9:44 pm
by sbbinc
APC BN1080G 650W.
Site has your switch powering 9 epmp radios, Two RB750GL and one Rasberry Pi.
Re: POE Staggered Start
Posted: Fri Dec 16, 2016 9:57 pm
by sirhc
sbbinc wrote:APC BN1080G 650W.
Site has your switch powering 9 epmp radios, Two RB750GL and one Rasberry Pi.
Yup, your UPS is too small.
viewtopic.php?f=17&t=2032&p=15275&hilit=+ups+inrush#p15275
Re: POE Staggered Start
Posted: Mon Dec 19, 2016 5:17 pm
by sbbinc
Not seen this issue at other sites that just have POE's.
All the gear on the site should pull 100 Watts max. So even if inrush was twice normal, that would be 200 watts, so 650 Watts should be plenty for the site.
If you think the issues is inrush then maybe 500ms is not long enough? Could we have the ability to set our own Staggered Start delay and sequence? If we set 8 seconds between devices maybe the inrush would not be a problem.
Re: POE Staggered Start
Posted: Mon Dec 19, 2016 5:33 pm
by sirhc
sbbinc wrote:Not seen this issue at other sites that just have POE's.
All the gear on the site should pull 100 Watts max. So even if inrush was twice normal, that would be 200 watts, so 650 Watts should be plenty for the site.
If you think the issues is inrush then maybe 500ms is not long enough? Could we have the ability to set our own Staggered Start delay and sequence? If we set 8 seconds between devices maybe the inrush would not be a problem.
If you read the link I gave you I explained that the inrush of the power supply in our switch requires a larger UPS.
Our power supply is rated at 250 watts sustained at 55C with the ability to handle momentary spikes much higher but in reality will push much more so the inrush is more than 250 watts, probably closer to 1000 watts which is why I suggest 1500 watt UPS.